Abstract Polyurea, a reaction product of isocyanates and an amine blend has been reported to be highly strain rate sensitive, which responds in its own unique way when subjected to increasing strain rates. The amine blend comprise of a long chain amine, forming the soft segments, chain extender, which brings the urea linkages closer and a crosslinker, which serves as a chemical bond between the chains. In this work, we attempt to tune the viscous contribution in polyurea, by increasing crosslinking density, while keeping the amount of chain extender more or less constant. The viscoelastic behavior and its effect on the time dependant behavior was established by extensive dynamic studies. Quasi-static tests and Split Hopkinson testing was performed over large deformation rates (10−4 to 103 s−1). It was observed that polyureas with larger viscous contribution (tan δ), were capable of exhibiting larger strain rate sensitivity.

中文翻译：

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聚脲涂料的应变率敏感性：粘性和弹性贡献

摘要 据报道，聚脲是异氰酸酯和胺混合物的反应产物，对应变速率非常敏感，当应变速率增加时，它会以自己独特的方式响应。胺混合物包含形成软链段的长链胺、使脲键更紧密的扩链剂和充当链之间化学键的交联剂。在这项工作中，我们尝试通过增加交联密度来调整聚脲中的粘性贡献，同时保持增链剂的量或多或少恒定。粘弹性行为及其对时间相关行为的影响是通过广泛的动态研究建立的。准静态测试和分裂霍普金森测试是在大变形率（10-4 到 103 s-1）下进行的。