Network Topology–Mechanical Properties Relationships of Model Elastomers
Network Topology–Mechanical Properties Relationships of Model Elastomers
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DOI：
10.1295/polymj.pj2008033
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发表时间：
2008-08
期刊：
影响因子：
2.8
通讯作者：
K. Urayama
中科院分区：
文献类型：
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作者：
K. Urayama
本文综述了近年来具有良好表征的网状结构的模型弹性体的力学性能。将已知分子量的聚二甲基硅氧烷（PDMS）与多功能交联剂端联制备模型弹性体。然后，我们在一般双轴应变下的应力-应变数据的基础上，严格评估了橡胶弹性的现代纠缠模型，该模型几乎涵盖了模型PDMS网络的所有可达变形范围。我们还证明了在稀释状态下从端链凝胶中去除溶剂制备的溶胀网络的显着可扩展性超过3000%。由相当致密的构象（超级线圈）组成的高度溶胀的网络表现出异常弱的应力应变依赖性。我们还研究了含有游离链或垂链的PDMS网络的粘弹性。前者为研究不变网络中客链的动力学提供了一个模型系统。客人链的动态，作为其自身大小的函数以及主机网络的网格大小，与重复理论的预测进行了比较。利用带有垂链的模型网络，阐明了垂链数量与阻尼性能的关系。具有高度不规则结构的弹性体具有高阻尼，几乎不受温度和频率的影响。
We review our recent studies on the mechanical properties of model elastomers with well-characterized network structures. Model elastomers were prepared by end-linking precursor poly(dimethylsiloxane) (PDMS) of known molecular weight with multifunctional crosslinkers. We then strictly assessed the modern entanglement models for rubber elasticity on the basis of the stress–strain data under general biaxial strains covering almost the entire range of accessible deformations for the model PDMS networks. We also demonstrated marked extensibility of more than 3000% for the deswollen networks prepared by removing the solvent from the end-linked gels prepared in the diluted state. The highly deswollen networks comprising the considerably compact conformation (supercoil) exhibited unusually weak strain dependence of stress. We also studied the viscoelastic properties of PDMS networks containing either unattached free chains or pendant chains. The former systems provided a model system to investigate the dynamics of the guest chains in invariant networks. The dynamics of the guest chains, as functions of their own sizes as well as the mesh sizes of host networks, were compared with the predictions of reptation theories. With the model networks with pendant chains, we elucidated the correlation between the damping properties and the amount of pendant chains. The elastomers with highly irregular structures exhibited high damping almost independent of both temperature and frequency.