等温和动态高温老化下苯基对有机硅网络性能演变的影响,Journal of Applied Polymer Science

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等温和动态高温老化下苯基对有机硅网络性能演变的影响
Journal of Applied Polymer Science ( IF 2.7 ) Pub Date : 2022-04-16 , DOI: 10.1002/app.52420
Philippe Banet ₁ , Linda Chikh ₁ , Thomas Fouet ₁ , Odile Fichet ₁

Affiliation

已对具有或不具有苯基的聚硅氧烷网络进行等温、热扫描和循环热处理，以研究热老化过程中苯基对其性能演变的影响。在等温老化下，含有 5 到 30 mol% 苯基的聚二甲基二苯基硅氧烷 (PDMDPS) 比聚二甲基硅氧烷 (PDMS) 更稳定，并且没有发现苯基含量的影响。因此，只有具有 5 mol% 苯基的 PDMS 和 PDMDPS 被保留用于在 150 至 300°C 等温处理期间监测它们的重量损失、拉伸应力、断裂伸长率和杨氏模量。同时记录循环老化过程中的重量损失和裂纹出现时间。测定了不同老化条件下的活化能，并且发现 PDMDPS 的重量损失（解聚反应的特性）等于 175 kJ/mol，机械性能（后交联反应的特性）等于 145-165 kJ/mol，以及 110 kJ/mol 和PDMS 分别为 125–145 kJ/mol。这些活化能证实含有苯基部分的有机硅比不含苯基的有机硅更热稳定。最后，根据经验，所有这些结果都允许将重量损失和机械性能的变化与热循环老化过程中裂纹的出现联系起来。这些活化能证实含有苯基部分的有机硅比不含苯基的有机硅更热稳定。最后，根据经验，所有这些结果都允许将重量损失和机械性能的变化与热循环老化过程中裂纹的出现联系起来。这些活化能证实含有苯基部分的有机硅比不含苯基的有机硅更热稳定。最后，根据经验，所有这些结果都允许将重量损失和机械性能的变化与热循环老化过程中裂纹的出现联系起来。

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Phenyl effect on properties evolution of silicone networks under isothermal and dynamic high temperature aging

Polysiloxane networks with or without phenyl groups have been subjected to isothermal, thermal sweep and cycling thermal treatments to investigate the phenyl effect on evolution of their properties during thermal aging. Polydimethyldiphenylsiloxanes (PDMDPS) containing between 5 and 30 mol% phenyl groups were more stable than polydimethylsiloxanes (PDMS) under isothermal aging, and no effect of the phenyl content was noted. Hence, only PDMS and PDMDPS with 5 mol% phenyl groups were then retained for the monitoring of their weight loss, tensile stress, elongation at break and Young's modulus during isothermal treatments between 150 and 300°C. Weight losses as well as the cracks appearance time during cycling aging were recorded simultaneously. The activation energies under the different aging conditions were determined, and found equal to 175 kJ/mol from the weight loss (characteristic of the depolymerization reaction) and 145–165 kJ/mol from the mechanical properties (characteristic of the post-cross-linking reaction) for PDMDPS, and 110 kJ/mol and 125–145 kJ/mol for PDMS, respectively. These activation energies confirm that silicone containing phenyl moieties are thermally more stable than those without. Finally, all these results empirically allow connecting weight loss and changes in mechanical properties to the appearance of cracks during thermal cycle aging.

更新日期：2022-04-16

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