Abstract Methylvinyldimethylsiloxane copolymer elastomer was crosslinked under static and dynamic conditions with several amounts of peroxide. For samples crosslinked in static conditions, the insoluble fractions and the shear equilibrium moduli have been observed in a good agreement with theories of network elasticity. As regards the dynamically crosslinked samples, the rheological and SEC analysis have revealed that the crosslinking reaction gives rise to multi-scale branched structures with molecular structures achieving 107 g/mol and proved that these samples remain soluble and processable. Moreover, dynamic crosslinked samples also show a strain hardening behavior even in bi-elongational flows. Furthermore, experiments under nitrogen and air atmospheres were carried out to better understand the mechanisms of the formation of these branched structures. The results suggest that molecular oxygen lowers the consumption of vinyl groups inhibiting the crosslinking reaction. Finally, the rheological behavior may be explained by the original microstructure composed of un-crosslinked chains playing the role of the matrix while the miscible and branched structures of macromolecules act as reinforcement agent.

中文翻译：

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有机硅弹性体的动态交联：通过剪切下的热氧化控制自由基支化

摘要 甲基乙烯基二甲基硅氧烷共聚物弹性体在静态和动态条件下与几种数量的过氧化物交联。对于在静态条件下交联的样品，观察到的不溶部分和剪切平衡模量与网络弹性理论非常一致。对于动态交联的样品，流变学和 SEC 分析表明，交联反应产生了多尺度支化结构，分子结构达到 107 g/mol，并证明这些样品保持可溶和可加工性。此外，动态交联样品即使在双拉伸流动中也表现出应变硬化行为。此外，在氮气和空气气氛下进行了实验，以更好地了解这些支链结构的形成机制。结果表明分子氧降低了抑制交联反应的乙烯基的消耗。最后，流变行为可能是由未交联的链组成的原始微观结构充当基体，而大分子的混溶和支化结构充当增强剂。