1
|
Li K, Kikugawa G, Kawagoe Y, Zhao Y, Okabe T. Determination of interaction parameters in a bottom-up approach employed in reactive dissipative particle dynamics simulations for thermosetting polymers. SOFT MATTER 2024. [PMID: 38805009 DOI: 10.1039/d3sm01743e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The limitations in previous dissipative particle dynamics (DPD) studies confined simulations to a narrow resin range. This study refines DPD parameter calculation methodology, extending its application to diverse polymer materials. Using a bottom-up approach with molecular dynamics (MD) simulations, we evaluated solubility parameters and bead number density governing nonbonded interactions via the Flory-Huggins parameter and covalent-bonded interactions. Two solubility parameter methods, Hildebrand and Krevelen-Hoftyzer, were compared for DPD simulations. The Hildebrand method, utilizing MD simulations, demonstrates higher consistency and broader applicability in determining solubility parameters for all DPD particles. The DPD/MD curing reaction process was examined in three epoxy systems: DGEBA/4,4'-DDS, DGEBA/MPDA and DGEBA/DETA. Calculations for the curing profile, gelation point, radial distribution function and branch ratio were performed. Compared to MD data for DGEBA/4,4'-DDS, the maximum deviation in secondary reactions between epoxy and amine groups according to DPD simulations with Krevelen-Hoftyzer was 14.8%, while with the Hildebrand method, it was 1.7%. The accuracy of the DPD curing reaction in reproducing the structural properties verifies its expanded application to general polymeric material simulations. The proposed curing DPD simulations, with a short run time and minimal computational resources, contributes to high-throughput screening for optimal resins and investigates mesoscopic inhomogeneous structures in large resin systems.
Collapse
Affiliation(s)
- Kaiwen Li
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
| | - Gota Kikugawa
- Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
| | - Yoshiaki Kawagoe
- Department of Aerospace Engineering, Graduate School of Engineering, Tohoku University, 6-6-01, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi, 980-8597, Japan
| | - Yinbo Zhao
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai, 200092, PR China
| | - Tomonaga Okabe
- Department of Aerospace Engineering, Graduate School of Engineering, Tohoku University, 6-6-01, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi, 980-8597, Japan
- Department of Materials Science and Engineering, University of Washington, BOX 352120, Seattle, WA 98195-1750, USA
- Research Center for Structural Materials, Polymer Matrix Hybrid Composite Materials Group, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| |
Collapse
|
2
|
Huang X, Wang X, Wang Q, Xu X, Zhao S. Promoting Cross-Link Reaction of Polymers by the Matrix-Filler Interface Effect: Role of Coupling Agents and Intermediate Linkers. J Phys Chem B 2024. [PMID: 38785140 DOI: 10.1021/acs.jpcb.4c02871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The matrix-filler interface effect plays an important role in determining the structural stability and mechanical properties of polymer composite materials, which remain ambiguous and need to be studied. The network-forming dynamics of poly(3,3-bis (azidomethyl) oxetane-tetrahydrofuran) (PBT) at the ammonium perchlorate (AP) surface was studied by using atomistic molecular dynamics simulation, considering the additives of curing agent toluene diisocyanate (TDI), cross-linker trimethylolpropane (TMP), and coupling agent triethanolamine (TEA). The presence of the AP surface promotes chain cross-link reaction, which is attributed to the increased production of intermediate linkers formed by TDI, TMP, and TEA. The intermediate linker has three reactive sites that can react with PBT main chains to form a cross-linked structure. Owing to the strong interaction with the AP surface, the coupling agent TEA plays a dominant role in forming the intermediate linker. At the early stage of network forming (reaction ratio r < 30%), the AP surface adsorbs TEA, which leads to a maximum contact density to PBT. As r increases to 60%, the density of intermediate linkers near the AP surface reaches a maximum value. Consequently, the chain cross-link reactions between the intermediate linker and PBT main chains are enhanced as r > 60%. This work explains the micromechanism of the promotion of chain cross-link reaction by the interface effect and provides important insights on designing polymer materials with high mechanical properties.
Collapse
Affiliation(s)
- Xin Huang
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xuan Wang
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Qijun Wang
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xiaofei Xu
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Shuangliang Zhao
- State Key Laboratory of Chemical Engineering and School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology and School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| |
Collapse
|
3
|
Karatrantos AV, Couture O, Hesse C, Schmidt DF. Molecular Simulation of Covalent Adaptable Networks and Vitrimers: A Review. Polymers (Basel) 2024; 16:1373. [PMID: 38794566 PMCID: PMC11125108 DOI: 10.3390/polym16101373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/22/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
Covalent adaptable networks and vitrimers are novel polymers with dynamic reversible bond exchange reactions for crosslinks, enabling them to modulate their properties between those of thermoplastics and thermosets. They have been gathering interest as materials for their recycling and self-healing properties. In this review, we discuss different molecular simulation efforts that have been used over the last decade to investigate and understand the nanoscale and molecular behaviors of covalent adaptable networks and vitrimers. In particular, molecular dynamics, Monte Carlo, and a hybrid of molecular dynamics and Monte Carlo approaches have been used to model the dynamic bond exchange reaction, which is the main mechanism of interest since it controls both the mechanical and rheological behaviors. The molecular simulation techniques presented yield sufficient results to investigate the structure and dynamics as well as the mechanical and rheological responses of such dynamic networks. The benefits of each method have been highlighted. The use of other tools such as theoretical models and machine learning has been included. We noticed, amongst the most prominent results, that stress relaxes as the bond exchange reaction happens, and that at temperatures higher than the glass transition temperature, the self-healing properties are better since more bond BERs are observed. The lifetime of dynamic covalent crosslinks follows, at moderate to high temperatures, an Arrhenius-like temperature dependence. We note the modeling of certain properties like the melt viscosity with glass transition temperature and the topology freezing transition temperature according to a behavior ruled by either the Williams-Landel-Ferry equation or the Arrhenius equation. Discrepancies between the behavior in dissociative and associative covalent adaptable networks are discussed. We conclude by stating which material parameters and atomistic factors, at the nanoscale, have not yet been taken into account and are lacking in the current literature.
Collapse
Affiliation(s)
- Argyrios V. Karatrantos
- Materials Research and Technology, Luxembourg Institute of Science and Technology, 5, Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg; (O.C.); (C.H.); (D.F.S.)
| | - Olivier Couture
- Materials Research and Technology, Luxembourg Institute of Science and Technology, 5, Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg; (O.C.); (C.H.); (D.F.S.)
- University of Luxembourg, 2, Avenue de l’Université, L-4365 Esch-sur-Alzette, Luxembourg
| | - Channya Hesse
- Materials Research and Technology, Luxembourg Institute of Science and Technology, 5, Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg; (O.C.); (C.H.); (D.F.S.)
- University of Luxembourg, 2, Avenue de l’Université, L-4365 Esch-sur-Alzette, Luxembourg
| | - Daniel F. Schmidt
- Materials Research and Technology, Luxembourg Institute of Science and Technology, 5, Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg; (O.C.); (C.H.); (D.F.S.)
| |
Collapse
|
4
|
Kashmari K, Patil SU, Kemppainen J, Shankara G, Odegard GM. Optimal Molecular Dynamics System Size for Increased Precision and Efficiency for Epoxy Materials. J Phys Chem B 2024; 128:4255-4265. [PMID: 38648370 DOI: 10.1021/acs.jpcb.4c00845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Molecular dynamics (MD) simulation is an important tool for predicting thermo-mechanical properties of polymer resins at the nanometer length scale, which is particularly important for efficient computationally driven design of advanced composite materials and structures. Because of the statistical nature of modeling amorphous materials on the nanometer length scale, multiple MD models (replicates) are typically built and simulated for statistical sampling of predicted properties. Larger replicates generally provide higher precision in the predictions but result in higher simulation times. Unfortunately, there is insufficient information in the literature to establish guidelines between MD model size and the resulting precision in predicted thermo-mechanical properties. The objective of this study was to determine the optimal MD model size of epoxy resin to balance efficiency and precision. The results show that an MD model size of 15,000 atoms provides for the fastest simulations without sacrificing precision in the prediction of mass density, elastic properties, strength, and thermal properties of epoxy. The results of this study are important for efficient computational process modeling and integrated computational materials engineering (ICME) for the design of next-generation composite materials for demanding applications.
Collapse
Affiliation(s)
- Khatereh Kashmari
- Michigan Technological University, Houghton, Michigan 49931, United States
| | - Sagar U Patil
- Michigan Technological University, Houghton, Michigan 49931, United States
| | - Josh Kemppainen
- Michigan Technological University, Houghton, Michigan 49931, United States
| | - Gowtham Shankara
- Michigan Technological University, Houghton, Michigan 49931, United States
| | - Gregory M Odegard
- Michigan Technological University, Houghton, Michigan 49931, United States
| |
Collapse
|
5
|
Tang Q, Jiang J, Li J, Zhao L, Xi Z. Effects of Chemical Composition and Cross-Linking Degree on the Thermo-Mechanical Properties of Bio-Based Thermosetting Resins: A Molecular Dynamics Simulation Study. Polymers (Basel) 2024; 16:1229. [PMID: 38732698 PMCID: PMC11085128 DOI: 10.3390/polym16091229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024] Open
Abstract
Bio-based epoxy resins have received significant attention in terms of concerns regarding carbon emission. Epoxidized soybean oil (ESO) derived from sustainable feedstock has been widely used to blend with traditional diglycidyl ether of bisphenol-A (DGEBA) to replace some of the petroleum-based components. In this work, molecular dynamics (MD) simulations were applied to track the network formation and predict the performance of methyl hexahydrophthalic anhydride (MHHPA)-cured ESO/DGEBA blend systems. The effects of ESO content and cross-linking degree on the mass density, volumetric shrinkage, glass transition temperature (Tg), coefficient of thermal expansion (CTE), Young's modulus, yield strength, and Poisson's ratio of the epoxy resin were systematically investigated. The results show that systems with high ESO content achieve gelation at low cross-linking degree. The Tg value, Young's modulus, and yield strength increase with the increase in cross-linking degree, but the CTE at the glassy state and Poisson's ratio decrease. The comparison results between the simulated and experimental data demonstrated that the MD simulations can accurately predict the thermal and mechanical properties of ESO-based thermosets. This study gains insight into the variation in thermo-mechanical properties of anhydride-cured ESO/DGEBA-based epoxy resins during the cross-linking process and provides a rational strategy for optimizing bio-based epoxy resins.
Collapse
Affiliation(s)
- Qiuyu Tang
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; (Q.T.); (J.L.); (L.Z.)
| | - Jie Jiang
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; (Q.T.); (J.L.); (L.Z.)
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Jinjin Li
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; (Q.T.); (J.L.); (L.Z.)
| | - Ling Zhao
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; (Q.T.); (J.L.); (L.Z.)
- Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Zhenhao Xi
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; (Q.T.); (J.L.); (L.Z.)
- Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| |
Collapse
|
6
|
Peeketi AR, Joseph E, Swaminathan N, Annabattula RK. Photo-activated dynamic isomerization induced large density changes in liquid crystal polymers: A molecular dynamics study. J Chem Phys 2024; 160:104902. [PMID: 38465687 DOI: 10.1063/5.0187320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 02/20/2024] [Indexed: 03/12/2024] Open
Abstract
We use molecular dynamics simulations to unravel the physics underpinning the light-induced density changes caused by the dynamic trans-cis-trans isomerization cycles of azo-mesogens embedded in a liquid crystal polymer network, an intriguing experimental observation reported in the literature. We employ two approaches, cyclic and probabilistic switching of isomers, to simulate dynamic isomerization. The cyclic switching of isomers confirms that dynamic isomerization can lead to density changes at specific switch-time intervals. The probabilistic switching approach further deciphers the physics behind the non-monotonous relation between density reduction and light intensities observed in experiments. Light intensity variations in experiments are accounted for in simulations by varying the trans-cis and cis-trans isomerization probabilities. The simulations show that an optimal combination of these two probabilities results in a maximum density reduction, corroborating the experimental observations. At such an optimal combination of probabilities, the dynamic trans-cis-trans isomerization cycles occur at a specific frequency, causing significant distortion in the polymer network, resulting in a maximum density reduction.
Collapse
Affiliation(s)
- Akhil Reddy Peeketi
- Center for Soft and Biological Matter, Indian Institute of Technology Madras, Chennai 600036, India
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | - Edwin Joseph
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | - Narasimhan Swaminathan
- Center for Soft and Biological Matter, Indian Institute of Technology Madras, Chennai 600036, India
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | - Ratna Kumar Annabattula
- Center for Soft and Biological Matter, Indian Institute of Technology Madras, Chennai 600036, India
- Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| |
Collapse
|
7
|
Zhou MH, Ao X, Islam M, Liu YY, Prolongo SG, Wang DY. Bio-based epoxy vitrimer with inherent excellent flame retardance and recyclability via molecular design. Int J Biol Macromol 2024; 262:129363. [PMID: 38244743 DOI: 10.1016/j.ijbiomac.2024.129363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/25/2023] [Accepted: 01/08/2024] [Indexed: 01/22/2024]
Abstract
The development of biobased fire-safe thermosets with recyclability heralds the switch for a transition towards a circular economy. In this framework, we introduced a novel high-performance bio-epoxy vitrimer (named GVD), which was fabricated by forming a crosslinking network between bio-epoxy glycerol triglycidyl ether (Gte), varying amounts of reactive flame-retardant agent 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) (0-7 wt%) and a vanillin-based hardener (VA) with imine bonds. For instance, the epoxy vitrimer GVD5, featuring a DOPO content of 5 wt%, achieved a V-0 rating in the vertical burning test (UL-94) and obtained a limiting oxygen index (LOI) value of 31 %, surpassing the performance of pristine epoxy. Furthermore, the peak heat release rate and total heat release of GVD5 were reduced by 38.2 % and 26.3 %, respectively, compared to pristine epoxy. The GVD vitrimers further demonstrated exceptional reprocessability and recyclability, attributed to the presence of dynamic imine bonds within the topological crosslinking network. Remarkably, the epoxy vitrimers maintained the mechanical properties of the parent epoxy. Therefore, this work provides a facile strategy for fabricating high-performance and multi-functional bio-epoxy thermosets.
Collapse
Affiliation(s)
- Mei-Hui Zhou
- Materials Science and Engineering Area, Universidad Rey Juan Carlos, Calle Tulipán s/n, 28933 Móstoles, Madrid, Spain; IMDEA Materials Institute, C/Eric Kandel, 2, 28906 Getafe, Madrid, Spain
| | - Xiang Ao
- IMDEA Materials Institute, C/Eric Kandel, 2, 28906 Getafe, Madrid, Spain; E.T.S. de Ingenieros de Caminos, Universidad Politécnica de Madrid, Calle profesor Aranguren 3, 28040 Madrid, Spain
| | - Monsur Islam
- IMDEA Materials Institute, C/Eric Kandel, 2, 28906 Getafe, Madrid, Spain
| | - Yu-Yao Liu
- IMDEA Materials Institute, C/Eric Kandel, 2, 28906 Getafe, Madrid, Spain; E.T.S. de Ingenieros de Caminos, Universidad Politécnica de Madrid, Calle profesor Aranguren 3, 28040 Madrid, Spain
| | - Silvia González Prolongo
- Materials Science and Engineering Area, Universidad Rey Juan Carlos, Calle Tulipán s/n, 28933 Móstoles, Madrid, Spain; Instituto de Tecnologías para la Sostenibilidad, Universidad Rey Juan Carlos, Calle Tulipán s/n, 28933 Móstoles, Madrid, Spain
| | - De-Yi Wang
- IMDEA Materials Institute, C/Eric Kandel, 2, 28906 Getafe, Madrid, Spain.
| |
Collapse
|
8
|
Kawagoe Y, Kikugawa G, Shirasu K, Kinugawa Y, Okabe T. Dissipative Particle Dynamics Simulation for Reaction-Induced Phase Separation of Thermoset/Thermoplastic Blends. J Phys Chem B 2024; 128:2018-2027. [PMID: 38373192 PMCID: PMC10911110 DOI: 10.1021/acs.jpcb.3c07756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 02/05/2024] [Accepted: 02/08/2024] [Indexed: 02/21/2024]
Abstract
Reaction-induced phase separation occurs during the curing reaction when a thermoplastic resin is dissolved in a thermoset resin, which enables toughening of the thermoset resin. As resin properties vary significantly depending on the morphology of the phase-separated structure, controlling the morphology formation is of critical importance. Reaction-induced phase separation is a phenomenon that ranges from the chemical reaction scale to the mesoscale dynamics of polymer molecules. In this study, we performed curing simulations using dissipative particle dynamics (DPD) coupled with a reaction model to reproduce reaction-induced phase separation. The curing reaction properties of the thermoset resin were determined by ab initio quantum chemical calculations, and the DPD parameters were determined by all-atom molecular dynamics simulations. This enabled mesoscopic simulations, including reactions that reflect the intrinsic material properties. The effects of the thermoplastic resin concentration, molecular weight, and curing conditions on the phase-separation morphology were evaluated, and the cure shrinkage and stiffness of each cured resin were confirmed to be consistent with the experimental trends. Furthermore, the local strain field under tensile deformation was visualized, and the inhomogeneous strain field caused by the phase-separated structures of two resins with different stiffnesses was revealed. These results can aid in understanding the toughening properties of thermoplastic additives at the molecular level.
Collapse
Affiliation(s)
- Yoshiaki Kawagoe
- Department
of Aerospace Engineering, Tohoku University, 6-6-01, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Gota Kikugawa
- Institute
of Fluid Science, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Keiichi Shirasu
- Department
of Finemechanics, Tohoku University, 6-6-01, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Yuuki Kinugawa
- Department
of Aerospace Engineering, Tohoku University, 6-6-01, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Tomonaga Okabe
- Department
of Aerospace Engineering, Tohoku University, 6-6-01, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
- Department
of Materials Science and Engineering, University
of Washington, P.O. Box 352120, Seattle, Washington 98195-1750, United States
- Research
Center for Structural Materials, Polymer Matrix Hybrid Composite Materials
Group, National Institute for Materials
Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| |
Collapse
|
9
|
Konrad J, Zahn D. Bottom-to-top modeling of epoxy resins: From atomic models to mesoscale fracture mechanisms. J Chem Phys 2024; 160:024111. [PMID: 38193558 DOI: 10.1063/5.0180355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/20/2023] [Indexed: 01/10/2024] Open
Abstract
We outline a coarse-grained model of epoxy resins (bisphenol-F-diglycidyl-ether/3,5-diethyltoluene-2,4-diamine) to describe elastic and plastic deformation, cavitation, and fracture at the μm scale. For this, molecular scale simulation data collected from quantum and molecular mechanics studies are coarsened into an effective interaction potential featuring a single type of beads that mimic 100 nm scale building blocks of the material. Our model allows bridging the time-length scale problem toward experimental tensile testing, thus effectively reproducing the deformation and fracture characteristics observed for strain rates of 10-1 to 10-5 s-1. This paves the way to analyzing viscoelastic deformation, plastic behavior, and yielding characteristics by means of "post-atomistic" simulation models that retain the molecular mechanics of the underlying epoxy resin at length scales of 0.1-10 µm.
Collapse
Affiliation(s)
- Julian Konrad
- Lehrstuhl für Theoretische Chemie, Computer Chemie Centrum, Friedrich-Alexander Universität Erlangen-Nürnberg, Nägelsbachstraße 25, 91052 Erlangen, Germany
| | - Dirk Zahn
- Lehrstuhl für Theoretische Chemie, Computer Chemie Centrum, Friedrich-Alexander Universität Erlangen-Nürnberg, Nägelsbachstraße 25, 91052 Erlangen, Germany
| |
Collapse
|
10
|
Gao C, Chen H, Dong X, Tang L, Chen D, Yan J, Xu H, Wu Z. An Accurate and Transferable Coarse-Graining Method for the Investigation of Microscopic Fracture Behaviors of Epoxy Thermosets. J Phys Chem B 2024; 128:393-404. [PMID: 38166404 DOI: 10.1021/acs.jpcb.3c07580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Coarse-grained modeling shows potential in exploring the thermo-mechanical behaviors of polymers applied in harsh conditions such as cryogenic environment, but its accuracy in simulating fracture behaviors of highly cross-linked epoxy thermosets is largely limited due to the complex molecular structures of the cross-linked networks. We address this fundamental problem by developing a CG modeling method where the backbones and electrostatic interaction (EI) contributions in the cross-linked networks are retained, and thus the potentials of the CG model can be directly extracted, or parametrized on the basis of, existing all-atomistic (AA) force fields. A multilevel parametrization procedure was adopted, where the bond potentials were parametrized relying on the results of density functional theory (DFT) simulation, whereas the nonbond potentials were parametrized by renormalizing the cohesive interaction strength. Remarkably, the CG model can reproduce stress-strain responses highly consistent with the AA simulation results at multiple stages, including elastic deformation, yielding, plastic flow, strain hardening, etc., and the straightforward parametrization procedure can be easily transferred to different materials and thermodynamic conditions. The CG modeling method was then used to build a large-scale representative volume element (RVE) to investigate the microscopic fracture behavior of an epoxy thermoset. It has been discovered that EI contributions play a significant role in generating correct mechanical responses and fracture morphologies. The influences of temperature (i.e., from room to cryogenic temperatures) and strain rates were discussed, and the fracture morphology in the RVE was unveiled and analyzed in a quantitative manner.
Collapse
Affiliation(s)
- Chang Gao
- School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| | - Hongzhi Chen
- School of Aeronautics and Astronautics, Faculty of Vehicle Engineering and Mechanics, State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, P. R. China
| | - Xufeng Dong
- School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| | - Lantian Tang
- School of Aeronautics and Astronautics, Faculty of Vehicle Engineering and Mechanics, State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, P. R. China
| | - Duo Chen
- School of Aeronautics and Astronautics, Faculty of Vehicle Engineering and Mechanics, State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, P. R. China
| | - Jia Yan
- School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| | - Hao Xu
- School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| | - Zhanjun Wu
- School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, P. R. China
| |
Collapse
|
11
|
Wylie L, Perli G, Duchet-Rumeau J, Livi S, Padua A. Thermodynamics of Tri- and Tetraepoxyimidazolium NTf 2 Amine Polyaddition: A Theoretical Perspective. J Phys Chem B 2023; 127:11074-11082. [PMID: 38099721 DOI: 10.1021/acs.jpcb.3c06554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
The thermodynamics of newly designed tri- and tetraepoxyimidazolium NTf2 monomers reacting with several diamines used as curing agents to form epoxy/amine thermosets was studied. The ability of each epoxy/amine combination to induce cross-linking both through the substitution of multiple epoxy groups and through multiple additions to a single amine was investigated. Through an increased understanding of the thermodynamics of epoxy-amine polymerization in complex polyepoxy-ILs, it is possible to more thoroughly understand the factors affecting the reactivity in these complex systems. These calculations showed that while each possible epoxy-amine combination was exergonic to both forms of cross-linking, the degree to which both amines-induced cross-linking and epoxy-induced cross-linking was favored varied between epoxy-amine combinations. Thermodynamic results obtained using density functional theory were experimentally validated through differential scanning calorimetry results, wherein similar trends were noted between theory and experiment. Among the trends noted in amines-epoxy combinations tested, tetraepoxyimidazolium NTf2/PACM (i.e., a cycloaliphatic diamine) was found to be a prime candidate for amine cross-linking, with the addition of a second epoxy to a single amine group being notably the most negative of all epoxy-amine combinations at -77.6 kJ mol-1. While in the case of epoxy cross-linking, the aliphatic polyetheramine denoted Jeffamine-D230-containing systems were found to be the most exergonic, with additions of primary amines to triepoxyimidazolium and tetraepoxyimidazolium NTf2 averaging -86.9 kJ mol-1. Interaction energy analysis indicated that the aromatic amine named sulfanilamide is the most favorable to engage in reactions due to having the most negative interaction energies with already highly substituted epoxy monomers. These results can be used to adjust the cross-linking possibilities of tri- and tetraepoxyimidazolium NTf2/amine polymerization and give insight into the predominant cross-linking reactions in these unique systems.
Collapse
Affiliation(s)
- Luke Wylie
- Laboratoire de Chimie, Ecole Normale Supérieure de Lyon, CNRS, Lyon 69342, France
| | - Gabriel Perli
- Université de Lyon, CNRS, UMR 5223, Ingénierie des Matériaux Polymères, INSA Lyon, F-69621 Villeurbanne, France
| | - Jannick Duchet-Rumeau
- Université de Lyon, CNRS, UMR 5223, Ingénierie des Matériaux Polymères, INSA Lyon, F-69621 Villeurbanne, France
| | - Sébastien Livi
- Université de Lyon, CNRS, UMR 5223, Ingénierie des Matériaux Polymères, INSA Lyon, F-69621 Villeurbanne, France
| | - Agilio Padua
- Laboratoire de Chimie, Ecole Normale Supérieure de Lyon, CNRS, Lyon 69342, France
| |
Collapse
|
12
|
Nie W, Douglas JF, Xia W. Competing Effects of Molecular Additives and Cross-Link Density on the Segmental Dynamics and Mechanical Properties of Cross-Linked Polymers. ACS ENGINEERING AU 2023; 3:512-526. [PMID: 38144677 PMCID: PMC10739619 DOI: 10.1021/acsengineeringau.3c00043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/30/2023] [Accepted: 10/06/2023] [Indexed: 12/26/2023]
Abstract
The introduction of molecular additives into thermosets often results in changes in their dynamics and mechanical properties that can have significant ramifications for diverse applications of this broad class of materials such as coatings, high-performance composites, etc. Currently, there is limited fundamental understanding of how such additives influence glass formation in these materials, a problem of broader significance in glass-forming materials. To address this fundamental problem, here, we employ a simplified coarse-grained (CG) model of a polymer network as a model of thermoset materials and then introduce a polymer additive having the same inherent rigidity and polymer-polymer interaction strength as the cross-linked polymer matrix. This energetically "neutral" or "self-plasticizing" additive model gives rise to non-trivial changes in the dynamics of glass formation and provides an important theoretical reference point for the technologically more important case of interacting additives. Based on this rather idealized model, we systematically explore the combined effect of varying the additive mass percentage (m) and cross-link density (c) on the segmental relaxation dynamics and mechanical properties of a model thermoset material with additives. We find that increasing the additive mass percentage m progressively decreases both the glass-transition temperature Tg and the fragility of glass formation, a trend opposite to increasing c so that these thermoset variables clearly have a competing effect on glass formation in these model materials. Moreover, basic mechanical properties (i.e., bulk, shear, and tensile moduli) likewise exhibit a competitive variation with the increase of m and c, which are strongly correlated with the Debye-Waller parameter ⟨u2⟩, a measure of material stiffness at a molecular scale. Our findings prove beneficial in the development of structure-property relationships for the cross-linked polymers, which could help guide the design of such network materials with tailored physical properties.
Collapse
Affiliation(s)
- Wenjian Nie
- Department
of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58108, United States
| | - Jack F. Douglas
- Materials
Science and Engineering Division, National
Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Wenjie Xia
- Department
of Aerospace Engineering, Iowa State University, Ames, Iowa 50011, United States
| |
Collapse
|
13
|
Shoji N, Yamashita T. Tensile Stress Reduction and Strain Concentration of Epoxy Resin Caused by Heterogeneity: A Multiscale Approach Combining Molecular Dynamics Simulation and Finite Element Method. J Phys Chem B 2023; 127:9066-9073. [PMID: 37844116 PMCID: PMC10615074 DOI: 10.1021/acs.jpcb.3c04391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/22/2023] [Indexed: 10/18/2023]
Abstract
In this study, we investigated the effect of heterogeneity on the mechanical properties of epoxy resin by combining coarse-grained molecular dynamics (CG-MD) and finite element method (FEM) simulations. To evaluate the heterogeneity effect in the uniaxial elongation, heterogeneous and homogeneous FEM models of micrometer-scale cubic epoxy resin were constructed. For the heterogeneous FEM model, parameters of nanometer-scale elements were determined by CG-MD simulations, where nanometer-scale blocks have different cross-linked structures. For the homogeneous FEM model, the averaged parameters were used for all elements. The calculated stress-strain (S-S) curves of the heterogeneous model exhibit similar tensile stress values when compared to the experimental data, whereas the homogeneous model yields notably higher values. Moreover, a clear strain concentration associated with the formation of the shear band-like structure was observed in the heterogeneous model and not in the homogeneous model.
Collapse
Affiliation(s)
- Naoyuki Shoji
- Laboratory
for Systems Biology and Medicine, Research Center for Advanced Science
and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
- NIPPON
STEEL Chemical & Material Co., Ltd., 1-13-1 Nihonbashi, Chuo-ku, Tokyo 103-0027, Japan
| | - Takefumi Yamashita
- Laboratory
for Systems Biology and Medicine, Research Center for Advanced Science
and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
- Department
of Physical Chemistry, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
| |
Collapse
|
14
|
Patil SU, Krieg AS, Odegard LK, Yadav U, King JA, Maiaru M, Odegard GM. Simple and convenient mapping of molecular dynamics mechanical property predictions of bisphenol-F epoxy for strain rate, temperature, and degree of cure. SOFT MATTER 2023; 19:6731-6742. [PMID: 37622445 DOI: 10.1039/d3sm00697b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
It is well-known that all-atom molecular dynamics (MD) predictions of mechanical properties of thermoset resins suffer from multiple accuracy issues associated with their viscoelastic nature. The nanosecond simulation times of MD simulations do not allow for the direct simulation of the molecular conformational relaxations that occur under laboratory time scales. This adversely affects the prediction of mechanical properties at realistic strain rates, intermediate degrees of cure, and elevated temperatures. While some recent studies have utilized a time-temperature superposition approach to relate MD predictions to expected laboratory observations, such an approach becomes prohibitively difficult when simulating thermosets with a combination of strain rates, intermediate degrees of cure, and temperatures. In this study, a phenomenological approach is developed to map the predictions of Young's modulus and Poisson's ratio for a DGEBF/DETDA epoxy system to the corresponding laboratory-based properties for intermediate degrees of cure and temperatures above and below the glass transition temperature. The approach uses characterization data from dynamical mechanical analysis temperature sweep experiments. The mathematical formulation and experimental characterization of the mapping is described, and the resulting mapping of computationally-predicted to experimentally-observed elastic properties for various degrees of cure and temperatures are demonstrated and validated. This mapping is particularly important to mitigate the strain-rate effect associated with MD predictions, as well as to accurately predict mechanical properties at elevated temperatures and intermediate degrees of cure to facilitate accurate and efficient composite material process modeling.
Collapse
Affiliation(s)
- Sagar U Patil
- Michigan Technological University, Houghton, MI-49931, USA.
| | - Aaron S Krieg
- Michigan Technological University, Houghton, MI-49931, USA.
| | - Leif K Odegard
- Michigan Technological University, Houghton, MI-49931, USA.
| | - Upendra Yadav
- Michigan Technological University, Houghton, MI-49931, USA.
| | - Julia A King
- Michigan Technological University, Houghton, MI-49931, USA.
| | | | | |
Collapse
|
15
|
Livraghi M, Pahi S, Nowakowski P, Smith DM, Wick CR, Smith AS. Block Chemistry for Accurate Modeling of Epoxy Resins. J Phys Chem B 2023; 127:7648-7662. [PMID: 37616478 PMCID: PMC10493980 DOI: 10.1021/acs.jpcb.3c04724] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 07/26/2023] [Indexed: 08/26/2023]
Abstract
Accurate molecular modeling of the physical and chemical behavior of highly cross-linked epoxy resins at the atomistic scale is important for the design of new property-optimized materials. However, a systematic approach to parametrizing and characterizing these systems in molecular dynamics is missing. We therefore present a unified scheme to derive atomic charges for amine-based epoxy resins, in agreement with the AMBER force field, based on defining reactive fragments─blocks─building the network. The approach is applicable to all stages of curing from pure liquid to gelation to fully cured glass. We utilize this approach to study DGEBA/DDS epoxy systems, incorporating dynamic topology changes into atomistic molecular dynamics simulations of the curing reaction with 127,000 atoms. We study size effects in our simulations and predict the gel point utilizing a rigorous percolation theory to recover accurately the experimental data. Furthermore, we observe excellent agreement between the estimated and the experimentally determined glass transition temperatures as a function of curing rate. Finally, we demonstrate the quality of our model by the prediction of the elastic modulus based on uniaxial tensile tests. The presented scheme paves the way for a broadly consistent approach for modeling and characterizing all amine-based epoxy resins.
Collapse
Affiliation(s)
- Mattia Livraghi
- Friedrich-Alexander-Universität
Erlangen-Nürnberg (FAU), Institute for Theoretical Physics,
PULS Group, Interdisciplinary Center for Nanostructured Films (IZNF), Cauerstrasse 3, Erlangen 91058, Germany
| | - Sampanna Pahi
- Friedrich-Alexander-Universität
Erlangen-Nürnberg (FAU), Institute for Theoretical Physics,
PULS Group, Interdisciplinary Center for Nanostructured Films (IZNF), Cauerstrasse 3, Erlangen 91058, Germany
| | - Piotr Nowakowski
- Group
for Computational Life Sciences, Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, Zagreb 10000, Croatia
| | - David M. Smith
- Group
for Computational Life Sciences, Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, Zagreb 10000, Croatia
| | - Christian R. Wick
- Friedrich-Alexander-Universität
Erlangen-Nürnberg (FAU), Institute for Theoretical Physics,
PULS Group, Interdisciplinary Center for Nanostructured Films (IZNF), Cauerstrasse 3, Erlangen 91058, Germany
| | - Ana-Sunčana Smith
- Friedrich-Alexander-Universität
Erlangen-Nürnberg (FAU), Institute for Theoretical Physics,
PULS Group, Interdisciplinary Center for Nanostructured Films (IZNF), Cauerstrasse 3, Erlangen 91058, Germany
- Group
for Computational Life Sciences, Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, Zagreb 10000, Croatia
| |
Collapse
|
16
|
Yao D, Feng C, Jin L, Zheng J, Fan R, Ming P. Improving Interfacial Adhesion of Graphite/Epoxy Composites by Surface Functionalization. ACS APPLIED MATERIALS & INTERFACES 2023; 15:39008-39016. [PMID: 37550802 DOI: 10.1021/acsami.3c08100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
Graphite/epoxy resin (G/EP) composites are extensively utilized in bipolar plates for fuel cells owing to their outstanding electrical and mechanical properties. However, the mechanical strength of these composites declines notably due to the inadequate bonding interface between graphite and epoxy resin. To address this issue, we used molecular dynamics (MD) simulations to study the influence of graphite surface functionalization on the interfacial structures of composites. The results of this study revealed that the functionalization of the graphite surface led to an increase in the interface thickness of the composite. This phenomenon can be attributed to the interdiffusion and hydrogen bond formation between functionalized graphite and epoxy molecular chains. And all four types of functional groups demonstrated a promoting effect on the adsorption process. Additionally, the adsorption and contact angle results provided further evidence that the adsorption rate of graphite to the epoxy resin significantly improved after functionalization. These findings contribute to a more comprehensive understanding of the microscopic process of forming interfaces in G/EP composites. In addition, these insights provide valuable guidance for improving the interface bonding of composite bipolar plates, which can ultimately increase their mechanical strength.
Collapse
Affiliation(s)
- Dongmei Yao
- Clean Energy Automotive Engineering Center and School of Automotive Studies, Tongji University, 4800 Caoan Road, Shanghai 201804, China
| | - Cong Feng
- College of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai 201804, China
| | - Liming Jin
- Clean Energy Automotive Engineering Center and School of Automotive Studies, Tongji University, 4800 Caoan Road, Shanghai 201804, China
| | - Junsheng Zheng
- Clean Energy Automotive Engineering Center and School of Automotive Studies, Tongji University, 4800 Caoan Road, Shanghai 201804, China
| | - Runlin Fan
- Clean Energy Automotive Engineering Center and School of Automotive Studies, Tongji University, 4800 Caoan Road, Shanghai 201804, China
| | - Pingwen Ming
- Clean Energy Automotive Engineering Center and School of Automotive Studies, Tongji University, 4800 Caoan Road, Shanghai 201804, China
| |
Collapse
|
17
|
Mousavifard SM, Ghermezcheshme H, Mirzaalipour A, Mohseni M, de With G, Makki H. PolySMart: a general coarse-grained molecular dynamics polymerization scheme. MATERIALS HORIZONS 2023; 10:2281-2296. [PMID: 37022310 DOI: 10.1039/d3mh00088e] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The development of simulation methods to study the structure and dynamics of a macroscopically sized piece of polymer material is important as such methods can elucidate structure-property relationships. Several methods have been reported to construct initial structures for homo- and co-polymers; however, most of them are only useful for short linear polymers since one needs to pack and equilibrate the far-from-equilibrium initial structures, which is a tedious task for long or hyperbranched polymers and unfeasible for polymer networks. In this method article, we present PolySMart, i.e., an open-source python package, which can effectively produce fully equilibrated homo- and hetero-polymer melts and solutions with no limitation on the polymer topology and size, at a coarse-grained resolution and through a bottom-up approach. This python package is also capable of exploring the polymerization kinetics through its reactive scheme in realistic conditions so that it can model the multiple co-occurring polymerization reactions (with different reaction rates) as well as consecutive polymerizations under stoichiometric and non-stoichiometric conditions. Thus, the equilibrated polymer models are generated through correct polymerization kinetics. A benchmark and verification of the performance of the program for several realistic cases, i.e., for homo-polymers, co-polymers, and crosslinked networks, is given. We further discuss the capability of the program to contribute to the discovery and design of new polymer materials.
Collapse
Affiliation(s)
- Seyyed Mohammad Mousavifard
- Department of Polymer and Color Engineering, Amirkabir University of Technology, 424 Hafez Ave., Tehran, Iran
| | - Hassan Ghermezcheshme
- Department of Polymer and Color Engineering, Amirkabir University of Technology, 424 Hafez Ave., Tehran, Iran
| | - Alireza Mirzaalipour
- Department of Polymer and Color Engineering, Amirkabir University of Technology, 424 Hafez Ave., Tehran, Iran
| | - Mohsen Mohseni
- Department of Polymer and Color Engineering, Amirkabir University of Technology, 424 Hafez Ave., Tehran, Iran
| | - Gijsbertus de With
- Laboratory of Physical Chemistry, Department of Chemical Engineering & Chemistry, Eindhoven University of Technology, POB 513, NL-5600 MB Eindhoven, The Netherlands
| | - Hesam Makki
- Department of Chemistry and Materials Innovation Factory, University of Liverpool, Liverpool L69 7ZD, UK.
| |
Collapse
|
18
|
Shi P, Zhu Y, Xu H, Yan C, Liu D, Yue L, Chen G. Insights into the carbonization mechanism of PAN-derived carbon precursor fibers and establishment of a kinetics-driven accelerated reaction template for atomistic simulation. Phys Chem Chem Phys 2023; 25:13946-13965. [PMID: 37190774 DOI: 10.1039/d2cp05196f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
To better understand the chemistry behind the carbonization process of the polyacrylonitrile (PAN)-based precursor fibers and provide a more authentic virtual counterpart of the process-inherited model for process optimization and rational performance design, we develop arrow-pushing reaction routes for primary exhaust gas product (H2O/H2/HCN/N2/tar vapor) formation and a pragmatic kinetics-driven accelerated reaction template for atomistic simulation of the carbonization process overcoming traditional challenges in time scale discrepancy of the reaction-diffusion system. The results of enthalpy barriers from hybrid first principles calculations validate the rationality and sequence of conjectured reactions during the two-stage carbonization process. Conversion rates of the rate-determining steps under 300 s carbonization are also estimated based on Eyring's transition state theory realizing kinetics equivalency of the reaction extent. Process-control measurements are further demonstrated corresponding to the proposed mechanism. The iterative densified crosslinking scheme specially designed for the surface layer is implanted into the topological reaction molecular dynamics template and a series of highly devisable structural models during the whole evolutionary process from the pre-oxidized fiber to the pristine carbon fiber surface are successfully predicted. The ultimate structure of the model presents excellent similarity in carbon yield and elemental composition with the type II high strength carbon fiber surface.
Collapse
Affiliation(s)
- Pengcheng Shi
- Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingdan Zhu
- Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haibing Xu
- Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
| | - Chun Yan
- Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
| | - Dong Liu
- Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
| | - Lingyu Yue
- Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
| | - Gang Chen
- Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China.
| |
Collapse
|
19
|
Alamfard T, Lorenz T, Breitkopf C. Thermal Conductivities of Uniform and Random Sulfur Crosslinking in Polybutadiene by Molecular Dynamic Simulation. Polymers (Basel) 2023; 15:polym15092058. [PMID: 37177204 PMCID: PMC10181005 DOI: 10.3390/polym15092058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/18/2023] [Accepted: 04/19/2023] [Indexed: 05/15/2023] Open
Abstract
Thermal conductivities of polybutadiene crosslinked with sulfur as a function of the heat flux autocorrelation function by using an equilibrium molecular dynamic (EMD) simulation were investigated. The Green-Kubo method was used to calculate thermal conductivities. All simulations were performed by applying the LAMMPS software (version 3 Mar 2020) package. The united-atom force field (OPLS-UA) from the Moltemplate software (version 2.20.3) was applied in the simulations. The influence of uniform and random distributions of sulfur in polybutadiene on the final value of thermal conductivities was studied by polymeric model structures with similar and variable degrees of crosslinking. The results showed that for identical degrees of crosslinking, the distribution of crosslinkers in the polymeric model structures significantly influenced the final value of thermal conductivity. Moreover, the influence of the crosslinking degree on the final value of thermal conductivity was studied by considering polymeric model structures with different degrees of crosslinking. The results demonstrate that by having a random distribution of sulfur, the thermal conductivity will be enhanced. However, by increasing the degree of crosslinking to the higher percentage in random crosslinked model structures, the value of thermal conductivity drops significantly due to possible higher crystallization of the model structures, which decrease the degree of freedom for phonon contributions.
Collapse
Affiliation(s)
- Tannaz Alamfard
- Chair of Thermodynamics, Technical University Dresden, 01069 Dresden, Germany
| | - Tommy Lorenz
- Chair of Thermodynamics, Technical University Dresden, 01069 Dresden, Germany
| | - Cornelia Breitkopf
- Chair of Thermodynamics, Technical University Dresden, 01069 Dresden, Germany
| |
Collapse
|
20
|
Orselly M, Richard C, Devémy J, Bouvet-Marchand A, Dequidt A, Loubat C, Malfreyt P. Impact of the Force Field on the Calculation of Density and Surface Tension of Epoxy-Resins. J Phys Chem B 2023; 127:2617-2628. [PMID: 36917513 DOI: 10.1021/acs.jpcb.2c09087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Abstract
The molecular simulation of interfacial systems is a matter of debate because of the choice of many input parameters that can affect significantly the performance of the force field of reproducing the surface tension and the coexisting densities. After developing a robust methodology for the calculation of the surface tension on a Lennard-Jones fluid, we apply it with different force fields to calculate the density and surface tension of pure constituents of epoxy resins. By using the model that best reproduces the experimental density and surface tension, we investigate the impact of composition in mass fraction on uncured epoxy resins and the effects of degree of cross-linking on cured resins.
Collapse
Affiliation(s)
- Mathilde Orselly
- Specific Polymers, 150 Avenue des Cocardières, 34160 Castries, France
| | - Cécile Richard
- Specific Polymers, 150 Avenue des Cocardières, 34160 Castries, France
| | - Julien Devémy
- Université Clermont Auvergne, CNRS, Clermont Auvergne INP, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France
| | | | - Alain Dequidt
- Université Clermont Auvergne, CNRS, Clermont Auvergne INP, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France
| | - Cédric Loubat
- Specific Polymers, 150 Avenue des Cocardières, 34160 Castries, France
| | - Patrice Malfreyt
- Université Clermont Auvergne, CNRS, Clermont Auvergne INP, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France
| |
Collapse
|
21
|
Yamada N, Oya Y, Kato N, Mori K, Koyanagi J. A Molecular Dynamics Simulation for Thermal Activation Process in Covalent Bond Dissociation of a Crosslinked Thermosetting Polymer. Molecules 2023; 28:molecules28062736. [PMID: 36985707 PMCID: PMC10056341 DOI: 10.3390/molecules28062736] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
A novel algorithm for covalent bond dissociation is developed to accurately predict fracture behavior of thermosetting polymers via molecular dynamics simulation. This algorithm is based on the Monte Carlo method that considers the difference in local strain and bond-dissociation energies to reproduce a thermally activated process in a covalent bond dissociation. This study demonstrates the effectiveness of this algorithm in predicting the stress-strain relationship of fully crosslinked thermosetting polymers under uniaxial tensile conditions. Our results indicate that the bond-dissociation energy plays an important role in reproducing the brittle fracture behavior of a thermosetting polymer by affecting the number of covalent bonds that are dissociated simultaneously.
Collapse
Affiliation(s)
- Naoki Yamada
- Department of Materials Science and Technology, Graduate School of Tokyo University of Science, Tokyo 125-8585, Japan
| | - Yutaka Oya
- Research Institute for Science & Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Nobuhiko Kato
- Sience and Engineering Systems Division ITOCHU Techno-Solutions Corporation, Tokyo 105-6950, Japan
| | - Kazuki Mori
- Sience and Engineering Systems Division ITOCHU Techno-Solutions Corporation, Tokyo 105-6950, Japan
| | - Jun Koyanagi
- Department of Materials Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| |
Collapse
|
22
|
Experimental Study and Molecular Simulation of the Effect of Temperature on the Stability of Surfactant Foam. Processes (Basel) 2023. [DOI: 10.3390/pr11030801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023] Open
Abstract
Temperature changes in CO2 foam-fracturing construction can easily affect surfactant foam stability. To investigate the effect of temperature on the foam stability of different types of surfactants, this study measured the foam half-life and viscosity of four typical surfactants, CTAB, LAS-30, HSB1214, and TX-10, using a novel self-designed and built foam performance measurement device. The effects of temperature on foam half-life and viscosity were studied. The results show that as the temperature increased, the half-life shortened, and the viscosity of the liquid phase decreased, which led to a decrease in foam stability. Moreover, using Materials Studio, a type of molecular simulation software, an interfacial model of the foam film was constructed to calculate the IFE and the self-diffusion coefficient of water molecules at 300 ps after the equilibrium of the foam system to investigate the mechanism of temperature influence on the stability of the foam. The results show that, for CTAB, LAS-30, HSB1214, and TX-10, the temperature increases from 15 °C to 45 °C, the IFE is enhanced by −50.05%, −59.10%, −64.21%, and −44.26%, respectively, the interfacial system changes from a low-energy state to a high-energy state, and the interfacial stability decreases. Meanwhile, Dwater increased 1.10-fold, 0.78-fold, 1.43-fold, and 0.64-fold, respectively, which accelerated the diffusion and migration of water molecules, weakened the intermolecular forces, and accelerated the instability of the foam system.
Collapse
|
23
|
Yan Y, Xu J, Liu S, Wang M, Yang C. Reactive force-field MD simulation on the pyrolysis process of phenolic with various cross-linked and branched structures. Chem Eng Sci 2023. [DOI: 10.1016/j.ces.2023.118606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
|
24
|
Schöller L, Nestler B, Denniston C. Modeling of a two-stage polymerization considering glass fibre sizing using molecular dynamics. NANOSCALE ADVANCES 2022; 5:106-118. [PMID: 36605801 PMCID: PMC9765651 DOI: 10.1039/d2na00562j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 11/15/2022] [Indexed: 06/17/2023]
Abstract
Fibre reinforced polymers are an important class of materials due to their light weight, high strength, and stiffness. However, there is a lack of knowledge about the interaction of fibre surface, sizing (fibre coating), and resin. Often only idealised academic systems are studied, and only rarely realistic systems that are used in an industrial context. Therefore, methods for studying the behaviour of complex sizing are highly desirable, especially as they play a crucial role in the performance of fibre reinforced polymers. Here, a simplified, yet industrially used resin system is extended using molecular dynamics simulations by adding a fibre surface and sizing layers. Furthermore, a common coupling agent was selected, and several additional assumptions were made about the structure of the sizing. Based on this, a systematic procedure for the development of a final cured system is introduced: a condensation reaction to form oligomers from coupling agent monomers is conducted. Subsequently, a two stage reaction, a polyurethane reaction and a radical polymerisation, is modelled based on an established approach. Using the final cured system, evaluations of averaged quantities during the reactions are carried out. Moreover, the system is evaluated along the normal direction of the fibre surface, which proves a spatial analysis of the fibre-sizing-resin interface.
Collapse
Affiliation(s)
- Lukas Schöller
- Institute for Applied Materials (IAM-MMS), Karlsruhe Institute of Technology (KIT) Kaiserstrasse 12 76131 Karlsruhe Germany
- Institute of Digital Materials Science (IDM), Karlsruhe University of Applied Sciences Moltkestrasse 30 76133 Karlsruhe Germany
| | - Britta Nestler
- Institute for Applied Materials (IAM-MMS), Karlsruhe Institute of Technology (KIT) Kaiserstrasse 12 76131 Karlsruhe Germany
- Institute of Digital Materials Science (IDM), Karlsruhe University of Applied Sciences Moltkestrasse 30 76133 Karlsruhe Germany
| | - Colin Denniston
- Department of Physics & Astronomy, University of Western Ontario (UWO) 1151 Richmond Street London ON N6A 3K7 Canada
| |
Collapse
|
25
|
Sahu S, Schwindt NS, Coscia BJ, Shirts MR. Obtaining and Characterizing Stable Bicontinuous Cubic Morphologies and Their Nanochannels in Lyotropic Liquid Crystal Membranes. J Phys Chem B 2022; 126:10098-10110. [PMID: 36417348 DOI: 10.1021/acs.jpcb.2c06119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Amphiphilic monomers in polar solvents can self-assemble into lyotropic liquid crystal (LLC) bicontinuous cubic structures under the right composition and temperature conditions. After cross-linking, the resulting polymer membranes with three-dimensional (3D) continuous uniform channels are excellent candidates for filtration applications. Designing such membranes with the desired physical and chemical properties requires molecular-level understanding of the structure, which can be obtained through molecular modeling. However, building molecular models of bicontinuous cubic structures is challenging due to their narrow regime of stability and the difficulty of self-assembly of large unit cells in molecular simulations. We developed a protocol for building stable bicontinuous cubic unit cells involving both parameterization and assembly of the components. We validate the theoretical structure against experimental results for one such LLC monomer and provide insight into the structure missing in experimental data, as well as demonstrate the qualitative nature of water and solute transport through these membranes.
Collapse
Affiliation(s)
- Subin Sahu
- Department of Chemical & Biological Engineering, University of Colorado Boulder, Boulder, Colorado80309, United States
| | - Nathanael S Schwindt
- Department of Chemical & Biological Engineering, University of Colorado Boulder, Boulder, Colorado80309, United States
| | - Benjamin J Coscia
- Department of Chemical & Biological Engineering, University of Colorado Boulder, Boulder, Colorado80309, United States
| | - Michael R Shirts
- Department of Chemical & Biological Engineering, University of Colorado Boulder, Boulder, Colorado80309, United States
| |
Collapse
|
26
|
Salehi A, Rash-Ahmadi S. Effect of adsorption, hardener, and temperature on mechanical properties of epoxy nanocomposites with functionalized graphene: A molecular dynamics study. J Mol Graph Model 2022; 117:108311. [PMID: 36087380 DOI: 10.1016/j.jmgm.2022.108311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 08/04/2022] [Accepted: 08/16/2022] [Indexed: 01/14/2023]
Abstract
Investigating Epoxy/hardener ratio and adsorption rate in epoxy/graphene oxide nanocomposites is of great importance, since these values can affect on the mechanical properties of the nanocomposite. In this study, molecular dynamics simulation was used to investigate and compare the mechanical properties of epoxy/graphene and graphene oxide nanocomposites (EPON 828, EPON 862, Epoxy Novolac, and Cycloaliphatic Epoxy with GNs and GO). Also, the effect of different weight percentages of graphene oxide (0,1,3 and 5 wt %), different weight percentages of epoxy compared to hardener, adsorption rate, and different temperatures were studied. The results showed that increasing the weight percentage of graphene oxide in epoxy matrices improved the adsorption rate between Epoxy/GO and the strength of nanocomposites. In addition, the amount of Young's modulus slightly decreased with increasing the temperature. Besides, the highest amount of Young modulus was obtained by increasing the weight percentage of epoxy to hardener at 63:37 wt %. Moreover, by comparing the mechanical properties of epoxy nanocomposites at 5 wt % graphene oxide, the highest Young modulus were found to be related to Novolac/GO 4.27 Gpa and EPON 862/GO 4.24 Gpa. This study contributes to a more comprehensive understanding on the behavior of the mechanical properties of epoxy/graphene oxide nanocomposites.
Collapse
Affiliation(s)
- Arman Salehi
- Department of Mechanical Engineering, Urmia University, Urmia, Iran
| | | |
Collapse
|
27
|
Zheng X, Guo Y, Douglas JF, Xia W. Competing Effects of Cohesive Energy and Cross-Link Density on the Segmental Dynamics and Mechanical Properties of Cross-Linked Polymers. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Xiangrui Zheng
- Department of Mechanics, School of Physical Science and Engineering, Beijing Jiaotong Uiversity, Beijing, 100044, China
| | - Yafang Guo
- Department of Mechanics, School of Physical Science and Engineering, Beijing Jiaotong Uiversity, Beijing, 100044, China
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Wenjie Xia
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58108, United States
| |
Collapse
|
28
|
Deng S, Xu W, Zhang J, Xu YG. Tunable mechanical properties of vulcanised styrene-butadiene rubber by regulating cross-linked molecular network structures. MOLECULAR SIMULATION 2022. [DOI: 10.1080/08927022.2022.2133152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Shengwei Deng
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, People’s Republic of China
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, People’s Republic of China
| | - Wentao Xu
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, People’s Republic of China
| | - Jing Zhang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, People’s Republic of China
| | - Yin-gen Xu
- Ningbo Runhe High-Tech Materials Co., Ltd., Ningbo, People’s Republic of China
| |
Collapse
|
29
|
Odegard GM, Patil SU, Gaikwad PS, Deshpande P, Krieg AS, Shah SP, Reyes A, Dickens T, King JA, Maiaru M. Accurate predictions of thermoset resin glass transition temperatures from all-atom molecular dynamics simulation. SOFT MATTER 2022; 18:7550-7558. [PMID: 36149371 DOI: 10.1039/d2sm00851c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
To enable the design and development of the next generation of high-performance composite materials, there is a need to establish improved computational simulation protocols for accurate and efficient prediction of physical, mechanical, and thermal properties of thermoset resins. This is especially true for the prediction of glass transition temperature (Tg), as there are many discrepancies in the literature regarding simulation protocols and the use of cooling rate correction factors for predicting values using molecular dynamics (MD) simulation. The objectives of this study are to demonstrate accurate prediction the Tg with MD without the use of cooling rate correction factors and to establish the influence of simulated conformational state and heating/cooling cycles on physical, mechanical, and thermal properties predicted with MD. The experimentally-validated MD results indicate that accurate predictions of Tg, elastic modulus, strength, and coefficient of thermal expansion are highly reliant upon establishing MD models with mass densities that match experiment within 2%. The results also indicate the cooling rate correction factors, model building within different conformational states, and the choice of heating/cooling simulation runs do not provide statistically significant differences in the accurate prediction of Tg values, given the typical scatter observed in MD predictions of amorphous polymer properties.
Collapse
Affiliation(s)
| | - Sagar U Patil
- Michigan Technological University, Houghton, MI 49931, USA.
| | | | | | - Aaron S Krieg
- Michigan Technological University, Houghton, MI 49931, USA.
| | - Sagar P Shah
- University of Massachusetts Lowell, MA 01854, USA
| | - Aspen Reyes
- Florida A&M University, Tallahassee, FL 32306, USA
| | | | - Julia A King
- Michigan Technological University, Houghton, MI 49931, USA.
| | | |
Collapse
|
30
|
Yuan L, Zhang C, Wang C, Wei N, Wan J, Zhu C, Fang H, Shi M. Effect of the crosslinking degree on the microstructure and thermomechanical properties of a polymer grouting material. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
31
|
Molecular Simulations and Network Analyses of Surface/Interface Effects in Epoxy Resins: How Bonding Adapts to Boundary Conditions. Polymers (Basel) 2022; 14:polym14194069. [PMID: 36236016 PMCID: PMC9573531 DOI: 10.3390/polym14194069] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 11/16/2022] Open
Abstract
In this study, we unravel the atomic structure of a covalent resin near boundaries such as surfaces and composite constituents. For this, a molecular simulation analysis of epoxy resin hardening under various boundary conditions was performed. On the atomic level of detail, molecular dynamics simulations were employed to study crosslinking reactions and self-organization of the polymer network within nm scale slab models. The resulting structures were then coarsened into a graph theoretical description for connectivity analysis of the nodes and combined with characterization of the node-to-node vector orientation. On this basis, we show that the local bonding of epoxy resins near interfaces tends to avoid under-coordinated linker sites. For both epoxy–vacuum surface models and epoxy–silica/epoxy cellulose interfaces, we find almost fully cured polymer networks. These feature a local increase in network linking lateral to the surface/interface, rather than the dangling of unreacted epoxy groups. Consequently, interface tension is low (as compared to the work of separating bulk epoxy), and the reactivity of the resin surface appears negligible.
Collapse
|
32
|
Orselly M, Devemy J, Bouvet-Marchand A, Dequidt A, Loubat C, Malfreyt P. Molecular Simulations of Thermomechanical Properties of Epoxy-Amine Resins. ACS OMEGA 2022; 7:30040-30050. [PMID: 36061676 PMCID: PMC9434774 DOI: 10.1021/acsomega.2c03071] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 08/01/2022] [Indexed: 06/15/2023]
Abstract
All-atom molecular dynamics (MD) simulations were performed with the CHARMM force field to characterize various epoxy resins, such as aliphatic and bisphenol-based resins. A multistep cross-linking algorithm was established, and key properties such as density, glass temperature, and elastic modulus were calculated. A quantitative comparison was made and was proven to be in good agreement with experimental data, with average absolute deviations between experiments and molecular simulation comprised between 2% and 12%. Additional findings on structure-property relationships were highlighted such as the effect of the cross-linking rate and oligomerization of the resin.
Collapse
Affiliation(s)
- Mathilde Orselly
- Specific
Polymers, 150 Avenue des Cocardières, 34160 Castries, France
- Université
Clermont Auvergne,Clermont Auvergne
INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France
| | - Julien Devemy
- Université
Clermont Auvergne,Clermont Auvergne
INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France
| | | | - Alain Dequidt
- Université
Clermont Auvergne,Clermont Auvergne
INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France
| | - Cédric Loubat
- Specific
Polymers, 150 Avenue des Cocardières, 34160 Castries, France
| | - Patrice Malfreyt
- Université
Clermont Auvergne,Clermont Auvergne
INP, CNRS, Institut de Chimie de Clermont-Ferrand, F-63000 Clermont-Ferrand, France
| |
Collapse
|
33
|
Zheng X, Guo Y, Douglas JF, Xia W. Understanding the role of cross-link density in the segmental dynamics and elastic properties of cross-linked thermosets. J Chem Phys 2022; 157:064901. [PMID: 35963735 DOI: 10.1063/5.0099322] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cross-linking is known to play a pivotal role in the relaxation dynamics and mechanical properties of thermoset polymers, which are commonly used in structural applications because of their light weight and inherently strong nature. Here, we employ a coarse-grained (CG) polymer model to systematically explore the effect of cross-link density on basic thermodynamic properties as well as corresponding changes in the segmental dynamics and elastic properties of these network materials upon approaching their glass transition temperatures (Tg). Increasing the cross-link density unsurprisingly leads to a significant slowing down of the segmental dynamics, and the fragility K of glass formation shifts in lockstep with Tg, as often found in linear polymer melts when the polymer mass is varied. As a consequence, the segmental relaxation time τα becomes almost a universal function of reduced temperature, (T - Tg)/Tg, a phenomenon that underlies the applicability of the "universal" Williams-Landel-Ferry (WLF) relation to many polymer materials. We also test a mathematical model of the temperature dependence of the linear elastic moduli based on a simple rigidity percolation theory and quantify the fluctuations in the local stiffness of the network material. The moduli and distribution of the local stiffness likewise exhibit a universal scaling behavior for materials having different cross-link densities but fixed (T - Tg)/Tg. Evidently, Tg dominates both τα and the mechanical properties of our model cross-linked polymer materials. Our work provides physical insights into how the cross-link density affects glass formation, aiding in the design of cross-linked thermosets and other structurally complex glass-forming materials.
Collapse
Affiliation(s)
- Xiangrui Zheng
- Department of Mechanics, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Yafang Guo
- Department of Mechanics, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Jack F Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Wenjie Xia
- Department of Civil, Construction and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58108, USA
| |
Collapse
|
34
|
Konrad J, Pfaller S, Zahn D. Multi-Scale Modelling of Plastic Deformation, Damage and Relaxation in Epoxy Resins. Polymers (Basel) 2022; 14:polym14163240. [PMID: 36015500 PMCID: PMC9415902 DOI: 10.3390/polym14163240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 08/02/2022] [Accepted: 08/04/2022] [Indexed: 11/21/2022] Open
Abstract
Epoxy resin plasticity and damage was studied from molecular dynamic simulations and interpreted by the help of constitutive modelling. For the latter, we suggested a physically motivated approach that aims at interpolating two well-defined limiting cases; namely, pulling at the vanishing strain rate and very rapid deformation; here, taken as 50% of the speed of sound of the material. In turn, to consider 0.1–10-m/s-scale deformation rates, we employed a simple relaxation model featuring exponential stress decay with a relaxation time of 1.5 ns. As benchmarks, deformation and strain reversal runs were performed by molecular dynamic simulations using two different strain rates. Our analyses show the importance of molecular rearrangements within the epoxy network loops for rationalizing the strain-rate dependence of plasticity and residual stress upon strain reversal. To this end, our constitutive model reasonably reproduced experimental data of elastic and visco-elastic epoxy deformation, along with the maximum stress experienced before fracturing. Moreover, we show the importance of introducing damage elements for mimicking the mechanical behavior of epoxy resins.
Collapse
Affiliation(s)
- Julian Konrad
- Lehrstuhl für Theoretische Chemie/Computer Chemie Centrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstr. 25, 91052 Erlangen, Germany
| | - Sebastian Pfaller
- Lehrstuhl für Technische Mechanik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 5, 91058 Erlangen, Germany
| | - Dirk Zahn
- Lehrstuhl für Theoretische Chemie/Computer Chemie Centrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstr. 25, 91052 Erlangen, Germany
- Correspondence:
| |
Collapse
|
35
|
Shundo A, Yamamoto S, Tanaka K. Network Formation and Physical Properties of Epoxy Resins for Future Practical Applications. JACS AU 2022; 2:1522-1542. [PMID: 35911459 PMCID: PMC9327093 DOI: 10.1021/jacsau.2c00120] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Epoxy resins are used in various fields in a wide range of applications such as coatings, adhesives, modeling compounds, impregnation materials, high-performance composites, insulating materials, and encapsulating and packaging materials for electronic devices. To achieve the desired properties, it is necessary to obtain a better understanding of how the network formation and physical state change involved in the curing reaction affect the resultant network architecture and physical properties. However, this is not necessarily easy because of their infusibility at higher temperatures and insolubility in organic solvents. In this paper, we summarize the knowledge related to these issues which has been gathered using various experimental techniques in conjunction with molecular dynamics simulations. This should provide useful ideas for researchers who aim to design and construct various thermosetting polymer systems including currently popular materials such as vitrimers over epoxy resins.
Collapse
Affiliation(s)
- Atsuomi Shundo
- Department
of Applied Chemistry and Center for Polymer Interface and
Molecular Adhesion Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Satoru Yamamoto
- Department
of Applied Chemistry and Center for Polymer Interface and
Molecular Adhesion Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Keiji Tanaka
- Department
of Applied Chemistry and Center for Polymer Interface and
Molecular Adhesion Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| |
Collapse
|
36
|
Yang J, Tao L, He J, McCutcheon JR, Li Y. Machine learning enables interpretable discovery of innovative polymers for gas separation membranes. SCIENCE ADVANCES 2022; 8:eabn9545. [PMID: 35857839 PMCID: PMC9299556 DOI: 10.1126/sciadv.abn9545] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 06/07/2022] [Indexed: 05/21/2023]
Abstract
Polymer membranes perform innumerable separations with far-reaching environmental implications. Despite decades of research, design of new membrane materials remains a largely Edisonian process. To address this shortcoming, we demonstrate a generalizable, accurate machine learning (ML) implementation for the discovery of innovative polymers with ideal performance. Specifically, multitask ML models are trained on experimental data to link polymer chemistry to gas permeabilities of He, H2, O2, N2, CO2, and CH4. We interpret the ML models and extract valuable insights into the contributions of different chemical moieties to permeability and selectivity. We then screen over 9 million hypothetical polymers and identify thousands that lie well above current performance upper bounds, including hundreds of never-before-seen ultrapermeable polymer membranes with O2 and CO2 permeability greater than 104 and 105 Barrers, respectively. High-fidelity molecular dynamics simulations confirm the ML-predicted gas permeabilities of the promising candidates, which suggests that many can be translated to reality.
Collapse
Affiliation(s)
- Jason Yang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Lei Tao
- Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Jinlong He
- Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Jeffrey R. McCutcheon
- Department of Chemical & Biomolecular Engineering, Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, USA
| | - Ying Li
- Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269, USA
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269, USA
- Corresponding author.
| |
Collapse
|
37
|
Shoji N, Sasaki K, Uedono A, Taniguchi Y, Hayashi K, Matsubara N, Kobayashi T, Yamashita T. Effect of conversion on epoxy resin properties: Combined molecular dynamics simulation and experimental study. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
38
|
Molecular Characterization of Membrane Gas Separation under Very High Temperatures and Pressure: Single- and Mixed-Gas CO2/CH4 and CO2/N2 Permselectivities in Hybrid Networks. MEMBRANES 2022; 12:membranes12050526. [PMID: 35629852 PMCID: PMC9143592 DOI: 10.3390/membranes12050526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 02/06/2023]
Abstract
This work illustrates the potential of using atomistic molecular dynamics (MD) and grand-canonical Monte Carlo (GCMC) simulations prior to experiments in order to pre-screen candidate membrane structures for gas separation, under harsh conditions of temperature and pressure. It compares at 300 °C and 400 °C the CO2/CH4 and CO2/N2 sieving properties of a series of hybrid networks based on inorganic silsesquioxanes hyper-cross-linked with small organic PMDA or 6FDA imides. The inorganic precursors are the octa(aminopropyl)silsesquioxane (POSS), which degrades above 300 °C, and the octa(aminophenyl)silsesquioxane (OAPS), which has three possible meta, para or ortho isomers and is expected to resist well above 400 °C. As such, the polyPOSS-imide networks were tested at 300 °C only, while the polyOAPS-imide networks were tested at both 300 °C and 400 °C. The feed gas pressure was set to 60 bar in all the simulations. The morphologies and densities of the pure model networks at 300 °C and 400 °C are strongly dependent on their precursors, with the amount of significant free volume ranging from ~2% to ~20%. Since measurements at high temperatures and pressures are difficult to carry out in a laboratory, six isomer-specific polyOAPS-imides and two polyPOSS-imides were simulated in order to assess their N2, CH4 and CO2 permselectivities under such harsh conditions. The models were first analyzed under single-gas conditions, but to be closer to the real processes, the networks that maintained CO2/CH4 and CO2/N2 ideal permselectivities above 2 were also tested with binary-gas 90%/10% CH4/CO2 and N2/CO2 feeds. At very high temperatures, the single-gas solubility coefficients vary in the same order as their critical temperatures, but the differences between the penetrants are attenuated and the plasticizing effect of CO2 is strongly reduced. The single-gas diffusion coefficients correlate well with the amount of available free volume in the matrices. Some OAPS-based networks exhibit a nanoporous behavior, while the others are less permeable and show higher ideal permselectivities. Four of the networks were further tested under mixed-gas conditions. The solubility coefficient improved for CO2, while the diffusion selectivity remained similar for the CO2/CH4 pair and disappeared for the CO2/N2 pair. The real separation factor is, thus, mostly governed by the solubility. Two polyOAPS-imide networks, i.e., the polyorthoOAPS-PMDA and the polymetaOAPS-6FDA, seem to be able to maintain their CO2/CH4 and CO2/N2 sieving abilities above 2 at 400 °C. These are outstanding performances for polymer-based membranes, and consequently, it is important to be able to produce isomer-specific polyOAPS-imides for use as gas separation membranes under harsh conditions.
Collapse
|
39
|
Determination of elastic constants of functionalized graphene-based epoxy nanocomposites: a molecular modeling and MD simulation study. J Mol Model 2022; 28:143. [PMID: 35543752 DOI: 10.1007/s00894-022-05134-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 04/30/2022] [Indexed: 10/18/2022]
Abstract
Functionalization of graphene is the best way to create a high degree of dispersion and bonding to polymer matrix in order to obtain high performance composites. The effects of carboxyl (-COOH) functionalized graphene (FG) on the mechanical properties of its epoxy-based nanocomposites have been examined by molecular dynamics (MD) simulations. Simulations cells of nanocomposites with varying wt% of FG (1, 2, and 3 wt%) were constructed using Material Studio 6.0. The MD simulation findings of nanocomposites reveal that they have better mechanical properties such as elastic modulus, bulk modulus, shear modulus, and the Poisson's ratio than pure epoxy. Furthermore, the computational results of nanocomposites have been effectively confirmed with available experimental data. Therefore, the current MD simulation shows a decent computational sign for the existing experimental and simulation outcomes on mechanical properties of FG/epoxy nanocomposites.
Collapse
|
40
|
Lee M, Ha MY, Lee M, Kim JH, Kim SD, Kim I, Lee WB. Aligned structures of mesogenic motifs in epoxy resin and their thermal conductivities. NANOSCALE ADVANCES 2022; 4:1970-1978. [PMID: 36133416 PMCID: PMC9417641 DOI: 10.1039/d1na00896j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 02/14/2022] [Indexed: 06/16/2023]
Abstract
The epoxy-based crosslinked polymer with the mesogenic group has been studied as a candidate resin material with high thermal conductivity due to the ordered structure of the mesogenic groups. In this study, we conducted all atomic molecular dynamics simulations with iterative crosslinking procedures on various epoxy resins with mesogenic motifs to investigate the effect of molecular alignment on thermal conductivity. The stacked structure of aromatic groups in the crosslinked polymer was analyzed based on the angle-dependent radial distribution function (ARDF), where the resins were categorized into three groups depending on their monomer shapes. The thermal conductivities of resins were higher than those of conventional polymers due to the alignment of aromatic groups, but no distinct correlation with the ARDF was found. Therefore, we conducted a further study about two structural factors that affect the alignment and the TC by comparing the resins within the same groups: the monomer with an alkyl spacer and functional groups in hardeners. The alkyl chains introduced in the epoxy monomers induced more stable stacking of aromatic groups, but thermal conductivity was lowered as they inhibited phonon transfer on the microscopic scale. In the other case, the functional groups in the hardener lowered the TC when the polar interaction with other polar groups in the monomer was strong enough to compete with the pi-pi interaction. These results represent how various chemical motifs in mesogenic groups affect their alignment on the atomistic scale, and also how they have effects on the TC consequently.
Collapse
Affiliation(s)
- Minhwan Lee
- School of Chemical and Biological Engineering, Seoul National University Seoul 08826 Republic of Korea
| | - Min Young Ha
- School of Chemical and Biological Engineering, Seoul National University Seoul 08826 Republic of Korea
| | - Mooho Lee
- Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd Gyeonggi-do 16678 Republic of Korea
| | - Ju Hyun Kim
- Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd Gyeonggi-do 16678 Republic of Korea
| | - Sung Dug Kim
- Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd Gyeonggi-do 16678 Republic of Korea
| | - In Kim
- Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd Gyeonggi-do 16678 Republic of Korea
| | - Won Bo Lee
- School of Chemical and Biological Engineering, Seoul National University Seoul 08826 Republic of Korea
| |
Collapse
|
41
|
Lian Q, Chen H, Luo Y, Li Y, Cheng J, Liu Y. Toughening mechanism based on the physical entanglement of branched epoxy resin in the non-phase-separated inhomogeneous crosslinking network: An experimental and molecular dynamics simulation study. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.124754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
42
|
Zhao Y, Kikugawa G, Kawagoe Y, Shirasu K, Kishimoto N, Xi Y, Okabe T. Uncovering the Mechanism of Size Effect on the Thermomechanical Properties of Highly Cross-Linked Epoxy Resins. J Phys Chem B 2022; 126:2593-2607. [PMID: 35325528 DOI: 10.1021/acs.jpcb.1c10827] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Epoxy resins are widely used as matrix resins, especially for carbon-fiber-reinforced plastic, due to their outstanding physical and mechanical properties. To date, most research into cross-linking processes using simulation has considered only a distance-based criterion to judge the probability of reaction. In this work, a new algorithm was developed for use with the large-scale atomic/molecular massively parallel simulator (LAMMPS) simulation package to study the cross-linking process; this new approach combines both a distance-based criterion and several kinetic criteria to identify whether the reaction has occurred. Using this simulation framework, we investigated the effect of model size on predicted thermomechanical properties of three different structural systems: diglycidyl ether of bisphenol A (DGEBA)/4,4'-diaminodiphenyl sulfone (4,4'-DDS), DGEBA/diethylenetriamine (DETA), and tetraglycidyl diaminodiphenylmethane (TGDDM)/4,4'-DDS. Derived values of gel point, volume shrinkage, and cross-linked resin density were found to be insensitive to model size in these three systems. Other thermomechanical properties, i.e., glass-transition temperature, Young's modulus, and yield stress, were found to reach stable values for systems larger than ∼40 000 atoms for both DGEBA/4,4'-DDS and DGEBA/DETA. However, these same properties modeled for TGDDM/4,4'-DDS did not stabilize until the system size reached 50 000 atoms. Our results provide general guidelines for simulation system size and procedures to more accurately predict the thermomechanical properties of epoxy resins.
Collapse
Affiliation(s)
- Yinbo Zhao
- Department of Aerospace Engineering, Tohoku University, 6-6-01, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan.,Institute of Fluid Science, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Gota Kikugawa
- Institute of Fluid Science, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Yoshiaki Kawagoe
- Department of Aerospace Engineering, Tohoku University, 6-6-01, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Keiichi Shirasu
- Department of Aerospace Engineering, Tohoku University, 6-6-01, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Naoki Kishimoto
- Department of Chemistry, Tohoku University, 6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Yingxiao Xi
- Department of Chemistry, Tohoku University, 6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Tomonaga Okabe
- Department of Aerospace Engineering, Tohoku University, 6-6-01, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan.,Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, Washington 98195, United States.,Research Center for Structural Materials, Polymer Matrix Hybrid Composite Materials Group, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| |
Collapse
|
43
|
Sridhar AS. Effect of stoichiometry on crosslinked epoxy resin characteristics: structural heterogeneities, topological defects, properties, free volume and segmental mobility. SOFT MATTER 2022; 18:2354-2372. [PMID: 35253035 DOI: 10.1039/d1sm01825f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Experimental studies have shown that changes in stoichiometry (R, ratio of amine groups to epoxy groups) cause considerable variations in the properties of epoxy-amine systems. Rationales based on free volume concepts have been routinely used to address these variations in properties but have hardly been satisfactorily substantiated. Many of these rationales remain as unverified conjectures to date. Substantiating these rationales will certainly bolster our understanding of the structure-stoichiometry-property relationship, but is difficult, due to inherent challenges involved in unambiguously characterizing the structural heterogeneities induced by changes in stoichiometry (structural heterogeneities include compositional distribution in the functionality of monomers, non-uniform dispersion of elastic chains and topological defects). The aim of the present work is to gain molecular-level insights into this relationship and to verify the rationales that rely on free volume concepts used for addressing the variations in properties with stoichiometry, with the help of all-atom molecular dynamics (MD) simulations. Five epoxy-amine systems with varying R ranging from 0.4 to 3, including the stoichiometric system (R = 1), were considered for these purposes. The properties of interest namely density, glass transition temperature (Tg) and thermal expansion coefficient in the rubbery state (αrl) of these systems were predicted. The local structure, fractional free volume and segmental mobility of these systems were then subsequently characterized as a function of stoichiometry and the results were analysed in detail. The role played by defects in properties and fractional free volume was then investigated. The results revealed significant insights into the compositional distribution of monomers with different functionalities as well as offered insights into the dispersion state and mobility of dangling chains, sols and elastic chains in the systems. Further, strong correlations were found between defect composition, fractional free volume at an elevated temperature (600 K) and thermomechanical properties (Tg and αrl) and it was established that the key mechanism underlying these correlations was the plasticization caused by defects. Analysis based on the rule of mixture models showed that these correlations were found to be in good agreement with the interpretations based on free volume concepts. The results also revealed a strong negative correlation between fractional free volume at room temperature and defect composition, a phenomenon typically associated with the antiplasticization effect.
Collapse
Affiliation(s)
- Arun Srikanth Sridhar
- Department of Fiber and Polymer Technology, The Royal Institute of Technology (KTH), 10044 Stockholm, Sweden.
| |
Collapse
|
44
|
Yarahmadi A, Hashemian M, Toghraie D, Abedinzadeh R, Ali Eftekhari S. Investigation of mechanical properties of epoxy-containing Detda and Degba and graphene oxide nanosheet using molecular dynamics simulation. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118392] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
45
|
Zhao F, Zhang H, Zhang D, Wang X, Wang D, Zhang J, Cheng J, Gao F. Molecular insights into the ‘defects’ network in the thermosets and the influence on the mechanical performance. RSC Adv 2022; 12:22342-22350. [PMID: 36105946 PMCID: PMC9364173 DOI: 10.1039/d2ra03099c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 06/23/2022] [Indexed: 11/26/2022] Open
Abstract
The introduction of ‘defects’ to the thermoset crosslinking network is one of the most applicable strategies for improving the modulus and toughness simultaneously. However, the reinforcement effect disappears when the ‘defects’ proportion exceeds the threshold. The speculated mechanism was that the aggregation and entanglement of the ‘defects’ chains changed the matrix topology, making the stacking structure more compact. However, the ‘defects’ are hardly directly observed in the experiment. As the result, the relationship between the ‘defects’ proportion and the package state of the matrix, and the effect on the material's mechanical performance was not explored. Herein, the network of bisphenol-A diglycidyl (DGEBA) with diethyltoluenediamine (DETDA) as the hardener was constructed using MD simulation, and n-butylamine was decorated on the matrix by replacing a proportion of DETDA acting as the ‘defects’. The results indicated that the aliphatic chains aggregated and entangled at a low concentration, occupying the voids in the rigid aromatic crosslinking structure, thus lowering the free volume. The strong non-bonding interactions drew the matrix segments close together, thus reinforcing the resin. However, the microphases formed by the aliphatic chains no longer filled the voids but created a new free volume and loosened the network when the content increased, which reduced the mechanical performance of the material. The experimental results were consistent with the findings in the simulations. The moduli of the resin increased with the increase in the n-butylamine content first and then declined. The maximum moduli of the thermosets was 3.4 GPa in S30, which was about 25% higher compared with the control; the corresponding elongation at break was 8.9%, which was about 46% improved compared with the control. The introduction of ‘defects’ to the thermoset crosslinking network is one of the most applicable strategies for improving the modulus and toughness simultaneously.![]()
Collapse
Affiliation(s)
- Fugui Zhao
- Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Haobo Zhang
- Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Dujuan Zhang
- Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Xiaomu Wang
- Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Dingxuan Wang
- Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Junying Zhang
- Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Jue Cheng
- Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Feng Gao
- Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| |
Collapse
|
46
|
Zhao Y, Zhang Z, Zhang S, Dou H, Yang K, Yang W. Molecular dynamics study on thermal and mechanical properties of
AOO
modified
DGEBA
‐anhydride insulating materials for high voltage
GIS. J Appl Polym Sci 2021. [DOI: 10.1002/app.51183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Yushun Zhao
- School of Electrical Engineering and Automation Hefei University of Technology Hefei China
| | - Ziyang Zhang
- School of Electrical Engineering and Automation Hefei University of Technology Hefei China
| | - Song Zhang
- School of Electrical Engineering and Automation Hefei University of Technology Hefei China
| | - Hongli Dou
- School of Electrical Engineering and Automation Hefei University of Technology Hefei China
| | - Kerong Yang
- School of Electrical Engineering and Automation Hefei University of Technology Hefei China
| | - Wei Yang
- State Key Laboratory of Advanced Power Transmission Technology State Grid Global Energy Interconnection Research Institute Beijing China
| |
Collapse
|
47
|
Livraghi M, Höllring K, Wick CR, Smith DM, Smith AS. An Exact Algorithm to Detect the Percolation Transition in Molecular Dynamics Simulations of Cross-Linking Polymer Networks. J Chem Theory Comput 2021; 17:6449-6457. [PMID: 34499497 DOI: 10.1021/acs.jctc.1c00423] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Periodic molecular dynamics simulations are developing to a routine tool for the investigation of complex, polymeric materials. A typical application is the simulation of the curing reaction of covalently cross-linked polymers, which provides detailed understanding of network formation at the molecular scale, with examples including gelation and glass transitions. In this article, we delineate the connection between percolation theory and gel-point detection in periodic polymeric networks. Specifically, we present an algorithm that can detect the onset of percolation during cross-linking of polymers in periodic molecular dynamic simulations. A sample implementation is provided at https://github.com/puls-group/percolation-analyzer. As an example, we apply the algorithm to simulations of an epoxy resin undergoing curing with an amine hardener. We also compare results with indirect gel point measurements obtained from monitoring the growth of the largest mass and the onset of secondary cycles.
Collapse
Affiliation(s)
- Mattia Livraghi
- PULS Group, Institute for Theoretical Physics and Interdisciplinary Center for Nanostructured Films (IZNF), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Cauerstraße 3, 91058 Erlangen, Germany
| | - Kevin Höllring
- PULS Group, Institute for Theoretical Physics and Interdisciplinary Center for Nanostructured Films (IZNF), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Cauerstraße 3, 91058 Erlangen, Germany
| | - Christian R Wick
- PULS Group, Institute for Theoretical Physics and Interdisciplinary Center for Nanostructured Films (IZNF), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Cauerstraße 3, 91058 Erlangen, Germany.,Competence Unit for Scientific Computing (CSC), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Martensstrasse 5a, 91058 Erlangen, Germany
| | - David M Smith
- Group of Computational Life Sciences, Division of Physical Chemistry, Ruder Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Ana-Sunčana Smith
- PULS Group, Institute for Theoretical Physics and Interdisciplinary Center for Nanostructured Films (IZNF), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Cauerstraße 3, 91058 Erlangen, Germany.,Group of Computational Life Sciences, Division of Physical Chemistry, Ruder Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| |
Collapse
|
48
|
Neyertz S, Brown D, Salimi S, Radmanesh F, Benes NE. Molecular characterization of polyOAPS-imide isomer hyper-cross-linked membranes: Free-volume morphologies and sorption isotherms for CH4 and CO2. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119531] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
49
|
Yan S, Verestek W, Zeizinger H, Schmauder S. Characterization of Cure Behavior in Epoxy Using Molecular Dynamics Simulation Compared with Dielectric Analysis and DSC. Polymers (Basel) 2021; 13:polym13183085. [PMID: 34577986 PMCID: PMC8469284 DOI: 10.3390/polym13183085] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/03/2021] [Accepted: 09/10/2021] [Indexed: 01/25/2023] Open
Abstract
The curing behavior of a thermosetting material that influences the properties of the material is a key issue for predicting the changes in material properties during processing. An empirical equation can describe the reaction kinetics of the curing behavior of an investigated material, which is usually estimated using experimental methods. In this study, the curing process of an epoxy resin, the polymer matrix in an epoxy molding compound, is computed concerning thermal influence using molecular dynamics. Furthermore, the accelerated reaction kinetics, which are influenced by an increased reaction cutoff distance, are investigated. As a result, the simulated crosslink density with various cutoff distances increases to plateau at a crosslink density of approx. 90% for the investigated temperatures during curing time. The reaction kinetics are derived according to the numerical results and compared with the results using experimental methods (dielectric analysis and differential scanning calorimetry), whereby the comparison shows a good agreement between experiment and simulation.
Collapse
|
50
|
Konrad J, Meißner RH, Bitzek E, Zahn D. A Molecular Simulation Approach to Bond Reorganization in Epoxy Resins: From Curing to Deformation and Fracture. ACS POLYMERS AU 2021; 1:165-174. [PMID: 36855655 PMCID: PMC9954341 DOI: 10.1021/acspolymersau.1c00016] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We model bond formation and dissociation processes in thermosetting polymer networks from molecular dynamics simulations. For this, a coarsened molecular mechanics model is derived from quantum calculations to provide effective interaction potentials that enable million-atoms scale simulations. The importance of bond (re)organization is demonstrated for (i) simulating epoxy resin formation-for which our approach leads to realistic network models which can now account for degrees of curing up to 98%. Moreover, (ii) we elucidate the competition of bond dissociation and bond reformation during plastic deformation and fracture. On this basis, we rationalize the molecular mechanisms that account for the irreversible nature of damaging epoxy polymers by mechanical load.
Collapse
Affiliation(s)
- Julian Konrad
- Department
of Chemistry and Pharmacy, Computer Chemistry Center, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, 91052, Germany
| | - Robert H. Meißner
- Institute
of Polymers and Composites, Hamburg University
of Technology, Hamburg, 21073, Germany,Helmholtz-Zentrum
Hereon, Institute of Surface Science, Geesthacht, 21502, Germany
| | - Erik Bitzek
- Department
of Materials Science and Engineering, Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91052, Germany
| | - Dirk Zahn
- Department
of Chemistry and Pharmacy, Computer Chemistry Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91052, Germany,
| |
Collapse
|