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Kraibut A, Kaewsakul W, Sahakaro K, Saiwari S, Noordermeer JWM, Dierkes WK. Degradation during Mixing of Silica-Reinforced Natural Rubber Compounds. Materials (Basel) 2024; 17:341. [PMID: 38255509 PMCID: PMC10821307 DOI: 10.3390/ma17020341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024]
Abstract
The optimal mixing conditions for silica-filled NR compounds dictate the need to proceed at a high temperature, i.e., 150 °C, to achieve a sufficient degree of silanization. On the other hand, natural rubber is prone to degradation due to mechanical shear and thermal effects during mixing, particularly at long exposure times. The present work investigates NR rubber degradation during mixing in relation to prolonged silanization times. The Mooney viscosity and stress relaxation rates, bound rubber content, storage modulus (G'), and delta δ were investigated to indicate the changes in the elastic/viscous responses of NR molecules related to rubber degradation, molecular chain modifications, and premature crosslinking/interaction. In Gum NR (unfilled), an increase in the viscous response with increasing mixing times indicates a major chain scission that causes a decreased molecular weight and risen chain mobility. For silica-filled NR, an initial decrease in the Mooney viscosity with increasing silanization time is attributed to the chain scission first, but thereafter the effect of the degradation is counterbalanced by a sufficient silanization/coupling reaction which leads to leveling off of the viscous response. Finally, the higher viscous response due to degradation leads to the deterioration of the mechanical properties and rolling resistance performance of tire treads made from such silica-filled NR, particularly when the silanization time exceeds 495 s.
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Affiliation(s)
- Ammarin Kraibut
- Department of Rubber Technology and Polymer Science, Faculty of Science and Technology, Prince of Songkla University, Pattani 94000, Thailand; (A.K.); (K.S.)
- Sustainable Elastomer Systems, Department of Mechanics of Solids, Surfaces and Systems, Faculty of Engineering Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Wisut Kaewsakul
- Elastomer Technology and Engineering, Department of Mechanics of Solids, Surfaces and Systems, Faculty of Engineering Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands;
| | - Kannika Sahakaro
- Department of Rubber Technology and Polymer Science, Faculty of Science and Technology, Prince of Songkla University, Pattani 94000, Thailand; (A.K.); (K.S.)
| | - Sitisaiyidah Saiwari
- Department of Rubber Technology and Polymer Science, Faculty of Science and Technology, Prince of Songkla University, Pattani 94000, Thailand; (A.K.); (K.S.)
| | | | - Wilma K. Dierkes
- Sustainable Elastomer Systems, Department of Mechanics of Solids, Surfaces and Systems, Faculty of Engineering Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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Thongnuek P, Kanokpanont S, Uttayarat P, Damrongsakkul S. Hydrogelation of Regenerated Silk Fibroin via Gamma Irradiation. Polymers (Basel) 2023; 15:3734. [PMID: 37765589 PMCID: PMC10535586 DOI: 10.3390/polym15183734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/03/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023] Open
Abstract
Gamma irradiation, which is one of the more conventional sterilization methods, was used to induce the hydrogelation of silk fibroin in this study. The physical and chemical characteristics of the irradiation-induced silk fibroin hydrogels were investigated. Silk fibroin solution with a concentration greater than 1 wt% formed hydrogel when irradiated by gamma rays at a dose of 25 or 50 kGy. The hydrogel induced by 50 kGy of radiation was more thermally stable at 80 °C than those induced by 25 kGy of radiation. When compared to the spontaneously formed hydrogels, the irradiated hydrogels contained a greater fraction of random coils and a lower fraction of β-sheets. This finding implies that gelation via gamma irradiation occurs via other processes, in addition to crystalline β-sheet formation, which is a well-established mechanism. Our observation suggests that crosslinking and chain scission via gamma irradiation could occur in parallel with the β-sheet formation. The irradiation-induced hydrogels were obtained when the solution concentration was adequate to support the radiation crosslinking of the silk fibroin chains. This work has, therefore, demonstrated that gamma irradiation can be employed as an alternative method to produce chemical-free, random coil-rich, and sterilized silk fibroin hydrogels for biomedical applications.
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Affiliation(s)
- Peerapat Thongnuek
- Center of Excellence in Biomaterial Engineering for Medical and Health, Chulalongkorn University, Bangkok 10330, Thailand; (P.T.); (S.D.)
- Biomedical Engineering Program, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
- Biomedical Engineering Research Center, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
| | - Sorada Kanokpanont
- Center of Excellence in Biomaterial Engineering for Medical and Health, Chulalongkorn University, Bangkok 10330, Thailand; (P.T.); (S.D.)
- Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
| | - Pimpon Uttayarat
- Research and Development Unit, Thailand Institute of Nuclear Technology (Public Organization), Nakhon Nayok 26120, Thailand;
| | - Siriporn Damrongsakkul
- Center of Excellence in Biomaterial Engineering for Medical and Health, Chulalongkorn University, Bangkok 10330, Thailand; (P.T.); (S.D.)
- Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
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Barney CW, Ye Z, Sacligil I, McLeod KR, Zhang H, Tew GN, Riggleman RA, Crosby AJ. Fracture of model end-linked networks. Proc Natl Acad Sci U S A 2022; 119:e2112389119. [PMID: 35145027 DOI: 10.1073/pnas.2112389119] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2022] [Indexed: 11/18/2022] Open
Abstract
Fracture of polymer networks is molecular in nature as chains must rupture for a crack to propagate. Predicting macroscopically measured fracture properties from molecular parameters a priori has remained elusive, even for well-defined networks. This work shows that a newly developed theory, which accounts for network defects, quantitatively describes both experimental measurements and molecular dynamics (MD) simulation data for fracture of a polymer network with independently defined or measured parameters. This advance provides a missing link between chemistry and materials science and engineering for polymer networks. Advances in polymer chemistry over the last decade have enabled the synthesis of molecularly precise polymer networks that exhibit homogeneous structure. These precise polymer gels create the opportunity to establish true multiscale, molecular to macroscopic, relationships that define their elastic and failure properties. In this work, a theory of network fracture that accounts for loop defects is developed by drawing on recent advances in network elasticity. This loop-modified Lake–Thomas theory is tested against both molecular dynamics (MD) simulations and experimental fracture measurements on model gels, and good agreement between theory, which does not use an enhancement factor, and measurement is observed. Insight into the local and global contributions to energy dissipated during network failure and their relation to the bond dissociation energy is also provided. These findings enable a priori estimates of fracture energy in swollen gels where chain scission becomes an important failure mechanism.
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Shim HE, Yeon YH, Lim DH, Nam YR, Park JH, Lee NH, Gwon HJ. Preliminary Study on the Simulation of a Radiation Damage Analysis of Biodegradable Polymers. Materials (Basel) 2021; 14:6777. [PMID: 34832188 DOI: 10.3390/ma14226777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/02/2021] [Accepted: 11/05/2021] [Indexed: 11/18/2022]
Abstract
In this study, biodegradable poly(L-lactide-co-ε-caprolactone) (PLCL) and poly(L-co-d,l lactide) (PLDLA) were evaluated using Geant4 (G4EmStandardPhysics_option4) for damage simulation, in order to predict the safety of these biodegradable polymers against gamma ray sterilization. In the PLCL damage model, both chain scission and crosslinking reactions appear to occur at a radiation dose in the range 0–200 kGy, but the chain cleavage reaction is expected to be relatively dominant at high irradiation doses above 500 kGy. On the other hand, the PLDLA damage model predicted that the chain cleavage reaction would prevail at the total irradiation dose (25–500 kGy). To verify the simulation results, the physicochemical changes in the irradiated PLCL and PLDLA films were characterized by GPC (gel permeation chromatography), ATR-FTIR (attenuated total reflection Fourier transform infrared), and DSC (difference scanning calorimetry) analyses. The Geant4 simulation curve for the radiation-induced damage to the molecular weight was consistent with the experimentally obtained results. These results imply that the pre-simulation study can be useful for predicting the optimal irradiation dose and ensuring material safety, particularly for implanted biodegradable materials in radiation processing.
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Lee DC, Kensy VK, Maroon CR, Long BK, Boydston AJ. The Intrinsic Mechanochemical Reactivity of Vinyl-Addition Polynorbornene. Angew Chem Int Ed Engl 2019; 58:5639-5642. [PMID: 30753753 DOI: 10.1002/anie.201900467] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Indexed: 11/08/2022]
Abstract
Herein we report the discovery of the intrinsic mechanochemical reactivity of vinyl-addition polynorbornene (VA-PNB), which has strained bicyclic ring repeat units along the polymer backbone. VA-PNBs with three different side chains were found to undergo ring-opening olefination upon sonication in dilute solutions. The sonicated polymers exhibited spectroscopic signatures consistent with conversion of the bicyclic norbornane repeat units into the ring-open isomer typical of polynorbornene made by ring-opening metathesis polymerization (ROMP-PNB). Thermal analysis and evaluation of chain-scission kinetics suggest that sonication of VA-PNB results in chain segments containing a statistical mixture of vinyl-added and ROMP-type repeat units.
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Affiliation(s)
- Daniel C Lee
- Molecular Engineering and Sciences, University of Washington, 3946 W Stevens Way NE, Seattle, WA, 98105, USA
| | - Victoria K Kensy
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA
| | - Christopher R Maroon
- Department of Chemistry, University of Tennessee, 320 Buehler Hall, Knoxville, TN, 37996-1600, USA
| | - Brian K Long
- Department of Chemistry, University of Tennessee, 320 Buehler Hall, Knoxville, TN, 37996-1600, USA
| | - Andrew J Boydston
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA, 98195-1700, USA.,Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI, 53706, USA
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Mizukado J, Sato H, Chen L, Suzuki Y, Yamane S, Aoyama Y, Suda H. High-resolution MALDI-TOF MS study on analysis of low-molecular-weight products from photo-oxidation of poly(3-hexylthiophene). J Mass Spectrom 2015; 50:1006-1012. [PMID: 28338270 DOI: 10.1002/jms.3614] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/13/2015] [Accepted: 05/09/2015] [Indexed: 06/06/2023]
Abstract
High-resolution matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOF MS) was used for the analysis of the low-molecular-weight products from the photo-oxidation of poly(3-hexylthiophene) (P3HT) in solution and thin film. Eight new peak series were observed in the low-mass range of the mass spectra of the products degraded in solution, and the formulas of the eight components were determined from the accurate mass. From SEC/MALDI-TOF MS, two components were identified as the degraded products, and the other six components were derived from the fragmentation of the degraded products during the MALDI process. A mechanism for the formation of these components was proposed on the basis of the results of MALDI-TOF MS. For the thin film degradation, a part of products in the solution degradation were observed, which supports that the oxidation of P3HT in solution and thin film proceeded in the same mechanism. This study shows that high-resolution MALDI-TOF MS is effective for the analysis of the low-molecular-weight products from P3HT photo-oxidation and expected to be feasible for the degradation analyses of other polymers. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Junji Mizukado
- National Institute of Advanced Industrial Science and Technology (AIST), Research Institute for Innovation in Sustainable Chemistry, Tsukuba, Ibaraki, 305-8565, Japan
| | - Hiroaki Sato
- National Institute of Advanced Industrial Science and Technology (AIST), Research Institute for Environmental Management Technology, Tsukuba, Ibaraki, 305-8569, Japan
| | - Liang Chen
- National Institute of Advanced Industrial Science and Technology (AIST), Research Institute for Innovation in Sustainable Chemistry, Tsukuba, Ibaraki, 305-8565, Japan
| | - Yasumasa Suzuki
- National Institute of Advanced Industrial Science and Technology (AIST), Research Institute for Innovation in Sustainable Chemistry, Tsukuba, Ibaraki, 305-8565, Japan
| | - Shogo Yamane
- National Institute of Advanced Industrial Science and Technology (AIST), Research Institute for Innovation in Sustainable Chemistry, Tsukuba, Ibaraki, 305-8565, Japan
| | - Yoshinori Aoyama
- National Institute of Advanced Industrial Science and Technology (AIST), Research Center for Photovoltaic Technologies, Tsukuba, Ibaraki, 305-8565, Japan
- Tokyo Institute of Technology, Interdisciplinary Graduate School of Science and Engineering, Midori-ku, Yokohama, 226-8503, Japan
| | - Hiroyuki Suda
- National Institute of Advanced Industrial Science and Technology (AIST), Research Institute for Innovation in Sustainable Chemistry, Tsukuba, Ibaraki, 305-8565, Japan
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