Yuxiang Sun, Xudong Wang, Yi Zhao, Xi Chen, Qian Shi, Kun Jia
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引用次数: 0
Abstract
Vitrimer, a class of covalent dynamic networks, is promising for polymeric applications requiring reshaping, recycling, and self-healing. The dynamic bonds in vitrimer can be reversibly broken and reformed under thermal actuation. This work investigates the effects of temperature on the fracture toughness of soft epoxy vitrimers. We measured the fracture toughness above the topology freezing temperature. Elevated temperatures reduce both fracture stretch and toughness, while they linearly increase the modulus. Given the invariant cross-linking density, the temperature dependence of fracture toughness is attributed to the sensitivity of the bond-exchange reactions. We extend the Lake–Thomas theory by incorporating kinetic bond scission to elucidate such dependence in epoxy vitrimers. Unlike conventional elastomers with a threshold of decreased fracture toughness at elevated temperatures, our theory indicates the continuous decrease of fracture toughness until approximating a zero value, aligning with the unique viscous behavior of vitrimers.
期刊介绍：
Macromolecules publishes original, fundamental, and impactful research on all aspects of polymer science. Topics of interest include synthesis (e.g., controlled polymerizations, polymerization catalysis, post polymerization modification, new monomer structures and polymer architectures, and polymerization mechanisms/kinetics analysis); phase behavior, thermodynamics, dynamic, and ordering/disordering phenomena (e.g., self-assembly, gelation, crystallization, solution/melt/solid-state characteristics); structure and properties (e.g., mechanical and rheological properties, surface/interfacial characteristics, electronic and transport properties); new state of the art characterization (e.g., spectroscopy, scattering, microscopy, rheology), simulation (e.g., Monte Carlo, molecular dynamics, multi-scale/coarse-grained modeling), and theoretical methods. Renewable/sustainable polymers, polymer networks, responsive polymers, electro-, magneto- and opto-active macromolecules, inorganic polymers, charge-transporting polymers (ion-containing, semiconducting, and conducting), nanostructured polymers, and polymer composites are also of interest. Typical papers published in Macromolecules showcase important and innovative concepts, experimental methods/observations, and theoretical/computational approaches that demonstrate a fundamental advance in the understanding of polymers.
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