In this study, polydimethylsiloxane (PDMS)-based covalent adaptable networks have been prepared in a one-pot, catalyst-free way in which dynamic β-amino esters (BAEs) are introduced via aza-Michael addition between available acrylate/amine-terminated PDMS-compounds. The straightforward introduction of those BAE-groups in such high-value elastomers provides the ability to relax the applied stress at elevated temperatures and hence the capability of reshaping the networks by compression molding at least 5 times without significant changes in properties. Moreover, the mechanical and dynamic properties are tunable by varying the cross-linker and/or filler content. Interestingly, the utilization of silica fillers not only enhances the network formation and mechanical properties but also accelerates the exchange reactions, resulting in twice faster stress relaxation at elevated temperatures while maintaining creep resistance at service temperatures.

中文翻译：

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基于 PDMS 的共价适应性弹性体的 Aza-Michael 化学：二氧化硅填料的设计和双重作用


在这项研究中，以一锅、无催化剂的方式制备了基于聚二甲基硅氧烷（PDMS）的共价适应性网络，其中通过可用丙烯酸酯/胺封端之间的氮杂迈克尔加成引入动态β-氨基酯（BAE） PDMS 化合物。在此类高价值弹性体中直接引入这些 BAE 基团，能够在高温下松弛所施加的应力，从而能够通过至少 5 次压缩成型来重塑网络，而不会显着改变性能。此外，机械和动态性能可通过改变交联剂和/或填料含量来调节。有趣的是，二氧化硅填料的使用不仅增强了网络形成和机械性能，而且还加速了交换反应，从而在高温下使应力松弛速度加快两倍，同时在使用温度下保持抗蠕变性。