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Pandya H, Khabaz F. Effect of dynamic bond concentration on the mechanical properties of vitrimers. Chem Commun (Camb) 2024; 60:10354-10357. [PMID: 39221558 DOI: 10.1039/d4cc03030c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The presence of dynamic covalent bonds allows vitrimers to undergo topology alterations and display self-healing properties. Herein, we study the influence of varying the concentration of dynamic bonds on the macroscopic properties of hybrid vitrimer networks by subjecting them to triaxial stretching tests using molecular simulations. Results show that the presence of dynamic bonds allows for continuous stress relaxation in the hybrid networks leading to delayed craze development and higher stretching as compared to permanently crosslinked networks. The work highlights the ability of glassy vitrimer networks to relax tensile stress during deformation successfully.
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Affiliation(s)
- Harsh Pandya
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH, 44325, USA
| | - Fardin Khabaz
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH, 44325, USA
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Akron, OH, 44325, USA.
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2
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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.
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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.)
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3
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Li Z, Zhao H, Duan P, Zhang L, Liu J. Manipulating the Properties of Polymer Vitrimer Nanocomposites by Designing Dual Dynamic Covalent Bonds. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:7769-7780. [PMID: 38551319 DOI: 10.1021/acs.langmuir.4c00699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Polymer vitrimer is a novel material that contains dynamic covalent bonds (DCBs) allowing it to combine the desirable characteristics of both thermoplastics and thermosets. Similar to the traditional polymer nanocomposites, introducing nanoparticles into polymer vitrimer is also an effective strategy to further enhance its properties. However, a comprehensive understanding of matrix and interfacial bond exchange reactions (BERs) to tailor the properties of polymer vitrimer nanocomposites (PVNs) is still lacking. Herein, we utilized coarse-grained molecular dynamics simulations to investigate model PVNs in which there are two different kinds of DCBs in the vitrimer matrix and at the interface. Our results show that the normalized bond autocorrelation function (Csw) confirms the independence of BERs in the vitrimer matrix and in the interface. By varying the bond swap energy barrier (Δ E sw ) in the matrix Δ E sw mat or in the interface Δ E sw int , or in both Δ E sw all , a maximum mechanical property is observed at the moderate value of Δ E sw mat , Δ E sw int , orΔ E sw all . Meanwhile, the effect of Δ E sw on the stress relaxation and the bond orientation as a function of the time under a fixed strain is well probed, which both decay more slowly at greater Δ E sw . We simulated the tension-recovery curve to examine the effect of Δ E sw on the hysteresis loss and permanent deformation of PVNs, finding an optimal value to achieve its minimum energy dissipation and maximum recovery ratio. Lastly, we investigated the efficiency of self-healing by building and removing walls from the system. Interestingly, a maximum self-healing efficiency of the stress-strain behavior is observed at moderate Δ E sw . Overall, this study provides valuable insights into the relationship between the structure and properties of PVNs, offering implications for the manipulation of their mechanical properties and enhancement of their self-healing capabilities.
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Affiliation(s)
- Zhenyuan Li
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Hengheng Zhao
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Pengwei Duan
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Liqun Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
- Institute of Emergent Elastomers, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, People's Republic of China
| | - Jun Liu
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
- Interdisciplinary Research Center for Artificial Intelligence, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
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Li K, Tran NV, Pan Y, Wang S, Jin Z, Chen G, Li S, Zheng J, Loh XJ, Li Z. Next-Generation Vitrimers Design through Theoretical Understanding and Computational Simulations. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2302816. [PMID: 38058273 PMCID: PMC10837359 DOI: 10.1002/advs.202302816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 09/03/2023] [Indexed: 12/08/2023]
Abstract
Vitrimers are an innovative class of polymers that boast a remarkable fusion of mechanical and dynamic features, complemented by the added benefit of end-of-life recyclability. This extraordinary blend of properties makes them highly attractive for a variety of applications, such as the automotive sector, soft robotics, and the aerospace industry. At their core, vitrimer materials consist of crosslinked covalent networks that have the ability to dynamically reorganize in response to external factors, including temperature changes, pressure variations, or shifts in pH levels. In this review, the aim is to delve into the latest advancements in the theoretical understanding and computational design of vitrimers. The review begins by offering an overview of the fundamental principles that underlie the behavior of these materials, encompassing their structures, dynamic behavior, and reaction mechanisms. Subsequently, recent progress in the computational design of vitrimers is explored, with a focus on the employment of molecular dynamics (MD)/Monte Carlo (MC) simulations and density functional theory (DFT) calculations. Last, the existing challenges and prospective directions for this field are critically analyzed, emphasizing the necessity for additional theoretical and computational advancements, coupled with experimental validation.
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Affiliation(s)
- Ke Li
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore
| | - Nam Van Tran
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Yuqing Pan
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Sheng Wang
- Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), Agency for Science, Technology and Research (A*STAR), Singapore, 138634, Singapore
| | - Zhicheng Jin
- Laboratory for Biomaterials and Drug Delivery, The Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Guoliang Chen
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Shuzhou Li
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Jianwei Zheng
- Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore, 138632, Republic of Singapore
| | - Xian Jun Loh
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore
- Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), Agency for Science, Technology and Research (A*STAR), Singapore, 138634, Singapore
| | - Zibiao Li
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore
- Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), Agency for Science, Technology and Research (A*STAR), Singapore, 138634, Singapore
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117576, Singapore
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Ferretti F, Damonte G, Cantamessa F, Arrigo R, Athanassiou A, Zych A, Fina A, Monticelli O. On a Biobased Epoxy Vitrimer from a Cardanol Derivative Prepared by a Simple Thiol-Epoxy "Click" Reaction. ACS OMEGA 2024; 9:1242-1250. [PMID: 38222589 PMCID: PMC10785085 DOI: 10.1021/acsomega.3c07459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/22/2023] [Accepted: 11/23/2023] [Indexed: 01/16/2024]
Abstract
The development of this work lies in the relevant interest in epoxy resins, which, despite their wide use, do not meet the requirements for sustainable materials. Therefore, the proposed approach considers the need to develop environmentally friendly systems, in terms of both the starting material and the synthetic method applied as well as in terms of end-of-life. The above issues were taken into account by (i) using a monomer from renewable sources, (ii) promoting the formation of dynamic covalent bonds, allowing for material reprocessing, and (iii) evaluating the degradability of the material. Indeed, an epoxy derived from cardanol was used, which, for the first time, was applied in the development of a vitrimer system. The exploitation of a diboronic ester dithiol ([2,2'-(1,4-phenylene)-bis[4-mercaptan-1,3,2-dioxaborolane], DBEDT) as a cross-linker allowed the cross-linking reaction to be carried out without the use of solvents and catalysts through a thiol-epoxy "click" mechanism. The dynamicity of the network was demonstrated by gel fraction experiments and rheological and DMA measurements. In particular, the formation of a vitrimer was highlighted, characterized by low relaxation times (around 4 s at 70 °C) and an activation energy of ca. 48 kJ/mol. Moreover, the developed material, which is easily biodegradable in seawater, was found to show promising flame reaction behavior. Preliminary experiments demonstrated that, unlike an epoxy resin prepared from the same monomer and using a classical cross-linker, our boron-containing material exhibited no dripping under combustion conditions, a phenomenon that will allow this novel biobased system to be widely used.
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Affiliation(s)
- Federico Ferretti
- Dipartimento
di Chimica e Chimica Industriale, Università
degli studi di Genova, Via Dodecaneso 31, 16146 Genoa, Italy
| | - Giacomo Damonte
- Dipartimento
di Chimica e Chimica Industriale, Università
degli studi di Genova, Via Dodecaneso 31, 16146 Genoa, Italy
| | - Francesco Cantamessa
- Dipartimento
di Scienza Applicata e Tecnologia, Politecnico
di Torino, Viale Teresa
Michel 5, 15121 Alessandria, Italy
| | - Rossella Arrigo
- Dipartimento
di Scienza Applicata e Tecnologia, Politecnico
di Torino, Viale Teresa
Michel 5, 15121 Alessandria, Italy
| | | | - Arkadiusz Zych
- Smart
Materials, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Alberto Fina
- Dipartimento
di Scienza Applicata e Tecnologia, Politecnico
di Torino, Viale Teresa
Michel 5, 15121 Alessandria, Italy
| | - Orietta Monticelli
- Dipartimento
di Chimica e Chimica Industriale, Università
degli studi di Genova, Via Dodecaneso 31, 16146 Genoa, Italy
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de Heer Kloots MHP, Schoustra SK, Dijksman JA, Smulders MMJ. Phase separation in supramolecular and covalent adaptable networks. SOFT MATTER 2023; 19:2857-2877. [PMID: 37060135 PMCID: PMC10131172 DOI: 10.1039/d3sm00047h] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Phase separation phenomena have been studied widely in the field of polymer science, and were recently also reported for dynamic polymer networks (DPNs). The mechanisms of phase separation in dynamic polymer networks are of particular interest as the reversible nature of the network can participate in the structuring of the micro- and macroscale domains. In this review, we highlight the underlying mechanisms of phase separation in dynamic polymer networks, distinguishing between supramolecular polymer networks and covalent adaptable networks (CANs). Also, we address the synergistic effects between phase separation and reversible bond exchange. We furthermore discuss the effects of phase separation on the material properties, and how this knowledge can be used to enhance and tune material properties.
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Affiliation(s)
- Martijn H P de Heer Kloots
- Laboratory of Organic Chemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
- Physical Chemistry and Soft Matter, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Sybren K Schoustra
- Laboratory of Organic Chemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Joshua A Dijksman
- Physical Chemistry and Soft Matter, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
| | - Maarten M J Smulders
- Laboratory of Organic Chemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
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Zhang J, Shi X, Lu H, Yu K, Fu YQ. Self-Toughening and Interfacial Welding of Covalent Adaptable Networks Undergoing Hydro-Chemo-Mechanical Coupling. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Jing Zhang
- National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin150080, PR China
| | - Xiaojuan Shi
- National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin150080, PR China
| | - Haibao Lu
- National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin150080, PR China
| | - Kai Yu
- Department of Mechanical Engineering, University of Colorado Denver, Denver, Colorado80217, United States
| | - Yong-Qing Fu
- Faculty of Engineering and Environment, University of Northumbria, Newcastle upon TyneNE1 8ST, U.K
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Gosecki M, Gosecka M. Boronic Acid Esters and Anhydrates as Dynamic Cross-Links in Vitrimers. Polymers (Basel) 2022; 14:842. [PMID: 35215755 PMCID: PMC8962972 DOI: 10.3390/polym14040842] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 02/12/2022] [Accepted: 02/14/2022] [Indexed: 12/02/2022] Open
Abstract
Growing environmental awareness imposes on polymer scientists the development of novel materials that show a longer lifetime and that can be easily recycled. These challenges were largely met by vitrimers, a new class of polymers that merges properties of thermoplastics and thermosets. This is achieved by the incorporation of dynamic covalent bonds into the polymer structure, which provides high stability at the service temperature, but enables the processing at elevated temperatures. Numerous types of dynamic covalent bonds have been utilized for the synthesis of vitrimers. Amongst them, boronic acid-based linkages, namely boronic acid esters and boroxines, are distinguished by their quick exchange kinetics and the possibility of easy application in various polymer systems, from commercial thermoplastics to low molecular weight thermosetting resins. This review covers the development of dynamic cross-links. This review is aimed at providing the state of the art in the utilization of boronic species for the synthesis of covalent adaptable networks. We mainly focus on the synthetic aspects of boronic linkages-based vitrimers construction. Finally, the challenges and future perspectives are provided.
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Affiliation(s)
- Mateusz Gosecki
- Centre of Molecular and Macromolecular Studies of the Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland;
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Zhao H, Wei X, Fang Y, Gao K, Yue T, Zhang L, Ganesan V, Meng F, Liu J. Molecular Dynamics Simulation of the Structural, Mechanical, and Reprocessing Properties of Vitrimers Based on a Dynamic Covalent Polymer Network. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c02034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Hengheng Zhao
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
- Beijing Engineering Research Center of Advanced Elastomers, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
| | - Xuefeng Wei
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yue Fang
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
- Beijing Engineering Research Center of Advanced Elastomers, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
| | - Ke Gao
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
- Beijing Engineering Research Center of Advanced Elastomers, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
| | - Tongkui Yue
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
- Beijing Engineering Research Center of Advanced Elastomers, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
| | - Liqun Zhang
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
- Beijing Engineering Research Center of Advanced Elastomers, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
| | - Venkat Ganesan
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Fanlong Meng
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Liu
- Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
- Beijing Engineering Research Center of Advanced Elastomers, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, People’s Republic of China
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10
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Wagner RJ, Hobbs E, Vernerey FJ. A network model of transient polymers: exploring the micromechanics of nonlinear viscoelasticity. SOFT MATTER 2021; 17:8742-8757. [PMID: 34528646 DOI: 10.1039/d1sm00753j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Dynamic networks contain crosslinks that re-associate after disconnecting, imparting them with viscoelastic properties. While continuum approaches have been developed to analyze their mechanical response, these approaches can only describe their evolution in an average sense, omitting local, stochastic mechanisms that are critical to damage initiation or strain localization. To address these limitations, we introduce a discrete numerical model that mesoscopically coarse-grains the individual constituents of a dynamic network to predict its mechanical and topological evolution. Each constituent consists of a set of flexible chains that are permanently cross-linked at one end and contain reversible binding sites at their free ends. We incorporate nonlinear force-extension of individual chains via a Langevin model, slip-bond dissociation through Eyring's model, and spatiotemporally-dependent bond attachment based on scaling theory. Applying incompressible, uniaxial tension to representative volume elements at a range of constant strain rates and network connectivities, we then compare the mechanical response of these networks to that predicted by the transient network theory. Ultimately, we find that the idealized continuum approach remains suitable for networks with high chain concentrations when deformed at low strain rates, yet the mesoscale model proves necessary for the exploration of localized stochastic events, such as variability of the bond kinetics, or the nucleation of micro-cavities that likely conceive damage and fracture.
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Affiliation(s)
- Robert J Wagner
- Department of Mechanical Engineering, Program of Materials Science and Engineering, University of Colorado, Boulder, USA.
| | - Ethan Hobbs
- Department of Mechanical Engineering, Program of Materials Science and Engineering, University of Colorado, Boulder, USA.
| | - Franck J Vernerey
- Department of Mechanical Engineering, Program of Materials Science and Engineering, University of Colorado, Boulder, USA.
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