Molecular dependencies of dynamic stiffening and strengthening through high strain rate microparticle impact of polyurethane and polyurea elastomers
Molecular dependencies of dynamic stiffening and strengthening through high strain rate microparticle impact of polyurethane and polyurea elastomers
复制标题
通过聚氨酯和聚脲弹性体的高应变率微粒影响动态硬化和强化的分子依赖性
DOI：
10.1063/1.5111964
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发表时间：
2019
影响因子：
4
通讯作者：
A. Hsieh
中科院分区：
文献类型：
--
作者：
Yuchen Sun;Y. Wu;D. Veysset;S. Kooi;Weiguo Hu;T. Swager;K. Nelson;A. Hsieh
本研究通过比较各种聚氨酯和聚脲的高应变率冲击响应，研究动态硬化和强化的分子依赖性。我们使用内部设计的桌面微冲击实验平台（激光诱导粒子冲击测试）来执行高应变率冲击并测量相应的材料响应。动态力学分析和差示扫描量热法表明玻璃化转变温度是环境温度下冲击响应的有用预测因子。同时，固态核磁共振波谱将节段动力学确定为动态硬化和强化变化的重要决定因素。聚氨酯和聚脲的冲击响应都显示出对软链段分子量的明显依赖性。这种比较表明分子间氢键的状态在动态硬化和强化中起着关键作用。本研究旨在确定冲击响应的分子依赖性，并为进一步设计和测试合成弹性体的最佳高应变率特性奠定基础。
This study investigates the molecular dependencies of dynamic stiffening and strengthening through comparison of high strain rate impact responses of various polyurethanes and polyureas. We use an in-house designed tabletop microimpact experimental platform—the laser-induced particle impact test—to perform high strain rate impacts and measure the corresponding material response. Dynamic mechanical analysis and differential scanning calorimetry are used to show that glass transition temperature is a useful predictor of the impact response at ambient temperatures. Meanwhile, solid-state nuclear magnetic resonance spectroscopy identifies segmental dynamics as an important determinant of the variation in both dynamic stiffening and strengthening. The impact responses of polyurethanes and polyureas both show clear dependencies on the molecular weight of the soft segment. This comparison suggests the state of intermolecular hydrogen bonding plays a key role in dynamic stiffening and strengthening. This study aims to identify the molecular dependencies of the impact response and establish a foundation for further design and testing of optimal high strain rate characteristics in synthetic elastomers.