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Pisani W, Wedgeworth DN, Burroughs JF, Thornell TL, Newman JK, Shukla MK. Micromechanical Dilution of PLA/PETG-Glass/Iron Nanocomposites: A More Efficient Molecular Dynamics Approach. ACS OMEGA 2024; 9:14887-14898. [PMID: 38585113 PMCID: PMC10993258 DOI: 10.1021/acsomega.3c08264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 02/23/2024] [Accepted: 03/04/2024] [Indexed: 04/09/2024]
Abstract
Polylactic acid (PLA) and poly(ethylene terephthalate glycol) (PETG) are popular thermoplastics used in additive manufacturing applications. The mechanical properties of PLA and PETG can be significantly improved by introducing fillers, such as glass and iron nanoparticles (NPs), into the polymer matrix. Molecular dynamics (MD) simulations with the reactive INTERFACE force field were used to predict the mechanical responses of neat PLA/PETG and PLA-glass/iron and PETG-glass/iron nanocomposites with relatively high loadings of glass/iron NPs. We found that the iron and glass NPs significantly increased the elastic moduli of the PLA matrix, while the PETG matrix exhibited modest increases in elastic moduli. This difference in reinforcement ability may be due to the slightly greater attraction between the glass/iron NP and PLA matrix. The NASA Multiscale Analysis Tool was used to predict the mechanical response across a range of volume percent glass/iron filler by using only the neat and highly loaded MD predictions as input. This provides a faster and more efficient approach than creating multiple MD models per volume percent per polymer/filler combination. To validate the micromechanics predictions, experimental samples incorporating hollow glass microspheres (MS) and carbonyl iron particles (CIP) into PLA/PETG were developed and tested for elastic modulus. The CIP produced a larger reinforcement in elastic modulus than the MS, with similar increases in elastic modulus between PLA/CIP and PETG/CIP at 7.77 vol % CIP. The micromechanics-based mechanical predictions compare excellently with the experimental values, validating the integrated micromechanical/MD simulation-based approach.
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Affiliation(s)
- William
A. Pisani
- Oak
Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831, United States
- Environmental
Laboratory, US Army Engineer Research and
Development Center, Vicksburg, Mississippi 39180, United States
| | - Dane N. Wedgeworth
- Geotechnical
and Structures Laboratory, US Army Engineer
Research and Development Center, Vicksburg, Mississippi 39180, United States
| | - Jedadiah F. Burroughs
- Geotechnical
and Structures Laboratory, US Army Engineer
Research and Development Center, Vicksburg, Mississippi 39180, United States
| | - Travis L. Thornell
- Geotechnical
and Structures Laboratory, US Army Engineer
Research and Development Center, Vicksburg, Mississippi 39180, United States
| | - J. Kent Newman
- Geotechnical
and Structures Laboratory, US Army Engineer
Research and Development Center, Vicksburg, Mississippi 39180, United States
| | - Manoj K. Shukla
- Environmental
Laboratory, US Army Engineer Research and
Development Center, Vicksburg, Mississippi 39180, United States
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Evers C, Vondrasek B, Jolowsky CN, Park JG, Czabaj MW, Ku BE, Thagard KR, Odegard GM, Liang Z. Scalable High Tensile Modulus Composite Laminates Using Continuous Carbon Nanotube Yarns for Aerospace Applications. ACS APPLIED NANO MATERIALS 2023; 6:11260-11268. [PMID: 37469508 PMCID: PMC10353548 DOI: 10.1021/acsanm.3c01266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/02/2023] [Indexed: 07/21/2023]
Abstract
An approach is established for fabricating high-strength and high-stiffness composite laminates with continuous carbon nanotube (CNT) yarns for scaled-up mechanical tests and potential aerospace structure applications. Continuous CNT yarns with up to 80% degree of nanotube alignment and a unique self-assembled graphitic CNT packing result in their specific tensile strengths of 1.77 ± 0.07 N/tex and an apparent specific modulus of 92.6 ± 3.2 N/tex. Unidirectional CNT yarn reinforced composite laminates with a CNT concentration of greater than 80 wt % and minimal microscale voids are fabricated using filament winding and aerospace-grade resin matrices. A specific tensile strength of up to 1.71 GPa/(g cm-3) and specific modulus of 256 GPa/(g cm-3) are realized; the specific modulus exceeds current state-of-the-art unidirectional carbon fiber composite laminates. The specific modulus of the laminates is 2.76 times greater than the specific modulus of the constituent CNT yarns, a phenomenon not observed in carbon fiber reinforced composites. The results demonstrate an effective approach for fabricating high-strength CNT yarns into composites for applications that require specific tensile modulus properties that are significantly beyond state-of-the-art carbon fiber composites and potentially open an unexplored performance region in the Ashby chart for composite material applications.
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Affiliation(s)
- Cecil
E. Evers
- FAMU-FSU
College of Engineering, High-Performance Materials Institute, Florida State University, 2005 Levy Avenue, Tallahassee, Florida 32311, United States
| | - Britannia Vondrasek
- Department
of Mechanical Engineering, University of
Utah, Salt Lake City, Utah 84112, United States
| | - Claire N. Jolowsky
- FAMU-FSU
College of Engineering, High-Performance Materials Institute, Florida State University, 2005 Levy Avenue, Tallahassee, Florida 32311, United States
| | - Jin Gyu Park
- FAMU-FSU
College of Engineering, High-Performance Materials Institute, Florida State University, 2005 Levy Avenue, Tallahassee, Florida 32311, United States
| | - Michael W. Czabaj
- Department
of Mechanical Engineering, University of
Utah, Salt Lake City, Utah 84112, United States
| | - Bailee E. Ku
- FAMU-FSU
College of Engineering, High-Performance Materials Institute, Florida State University, 2005 Levy Avenue, Tallahassee, Florida 32311, United States
| | - Kaylee R. Thagard
- FAMU-FSU
College of Engineering, High-Performance Materials Institute, Florida State University, 2005 Levy Avenue, Tallahassee, Florida 32311, United States
| | - Gregory M. Odegard
- Mechanical
Engineering—Engineering Mechanics, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Zhiyong Liang
- FAMU-FSU
College of Engineering, High-Performance Materials Institute, Florida State University, 2005 Levy Avenue, Tallahassee, Florida 32311, United States
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Haber RT, Browning AR, Graves BR, Davis WP, Wiggins JS. A Molecular Dynamics Study of Monomer Melt Properties of Cyanate Ester Monomer Melt Properties. Polymers (Basel) 2022; 14:polym14061219. [PMID: 35335549 PMCID: PMC8951156 DOI: 10.3390/polym14061219] [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: 02/10/2022] [Revised: 03/07/2022] [Accepted: 03/11/2022] [Indexed: 01/27/2023] Open
Abstract
The objective of this work was to computationally predict the melting temperature and melt properties of thermosetting monomers used in aerospace applications. In this study, we applied an existing voids method by Solca. to examine four cyanate ester monomers with a wide range of melting temperatures. Voids were introduced into some simulations by removal of molecules from lattice positions to lower the free-energy barrier to melting to directly simulate the transition from a stable crystal to amorphous solid and capture the melting temperature. We validated model predictions by comparing melting temperature against previously reported literature values. Additionally, the torsion and orientational order parameters were used to examine the monomers’ freedom of motion to investigate structure–property relationships. Ultimately, the voids method provided reasonable estimates of melting temperature while the torsion and order parameter analysis provided insight into sources of the differing melt properties between the thermosetting monomers. As a whole, the results shed light on how freedom of molecular motions in the monomer melt state may affect melting temperature and can be utilized to inspire the development of thermosetting monomers with optimal monomer melt properties for demanding applications.
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Affiliation(s)
- Rebecca T. Haber
- School of Polymer Science and Engineering, University of Southern Mississippi, 118 College Dr, #5050, Hattiesburg, MS 39406, USA; (R.T.H.); (B.R.G.)
| | | | - Bayleigh R. Graves
- School of Polymer Science and Engineering, University of Southern Mississippi, 118 College Dr, #5050, Hattiesburg, MS 39406, USA; (R.T.H.); (B.R.G.)
| | - William P. Davis
- Department of Mathematics, Western Washington University, 516 High St., Bellingham, WA 98225, USA;
| | - Jeffrey S. Wiggins
- School of Polymer Science and Engineering, University of Southern Mississippi, 118 College Dr, #5050, Hattiesburg, MS 39406, USA; (R.T.H.); (B.R.G.)
- Correspondence:
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Khare KS, Abrams CF. Atomistic simulation of volumetric properties of epoxy networks: effect of monomer length. SOFT MATTER 2021; 17:9957-9966. [PMID: 34698327 DOI: 10.1039/d1sm01128f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Properties of epoxy thermosets can be varied broadly to suit design requirements by altering the chemistry of the component agents. Atomistically-detailed molecular dynamics simulations are well-suited for molecular insight into the structure-property relationship for a rational tailoring of the chemistry. Since the macroscopic properties of interest for applications emerge hierarchically from molecular-scale chemical interactions, seamless integration of experiment, computation, and theory is of great interest. Recently, a Specific Volume-Cooling Rate analysis protocol was successfully developed to quantitatively compare the volumetric properties of an epoxy network model with experimental results in the literature, in spite of the nine orders of magnitude mismatch in the accessible time-scales. Here, we extend the application of the method for two epoxy networks in the same class of chemistry but whose monomers have a higher number of repeating units compared to the previous one for validating the generality of our approach. We observed that atomistic simulations are able to predict the experimental temperature trend of the specific volume within 0.4% for both these networks. Using the William-Landel-Ferry equation to account for rate differences, we also see good agreement between the computational and experimental values of the glass transition temperature.
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Affiliation(s)
- Ketan S Khare
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA.
| | - Cameron F Abrams
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA.
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