聚烯烃
聚合物
战术性
断链
硫化
分子动力学
聚苯乙烯
材料科学
高分子化学
支化(高分子化学)
弹性体
弹性(物理)
分手
聚丙烯
橡胶弹性
聚乙烯
化学
天然橡胶
计算化学
复合材料
聚合
物理
图层(电子)
机械
作者
Nima Fakhrayi Mofrad,Pedram Bahadori,Guido Raos
出处
期刊:Macromolecules
[American Chemical Society]
日期:2024-04-20
卷期号:57 (9): 3901-3913
标识
DOI:10.1021/acs.macromol.3c02609
摘要
There has been a growing interest in the ultimate mechanical properties of single polymer chains, as they are related to the fracture toughness of solid polymers, networks, and gels, and to the processability of their melts and solutions. The breakup of a polymer chain under tension is also a quintessential, albeit rather crude, example of a mechanochemical reaction. We simulate this phenomenon in polyethylene, polypropylene, and polystyrene single chains by Langevin dynamics with a reactive force field capable of describing bond dissociation in a chemically realistic way. The force–elongation curves show a clear transition between entropic and enthalpic elasticity, followed by chain scission at elongations that generally exceed the nominal contour length of the chains. We highlight an intriguing dependence of the chains' mechanical properties on the chain tacticity. Somewhat unexpectedly, chain scission may often lead to the formation of three or more fragments depending also on the chains' stereochemistry and the relaxation time of the Langevin thermostat employed in the simulations.
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