烷氧基封端107硅橡胶的研制及应用

Preparation and Application of Alkoxy-Terminated 107 Silicone Rubber

采用烷氧基硅烷对α,ω-二羟基聚二甲基硅氧烷(107硅橡胶)进行改性制得烷氧基封端107硅橡胶,考察了封端反应催化剂种类和用量、封端剂种类、封端时反应温度和反应时间对封端效果的影响,并测试了烷氧基封端107硅橡胶作基础聚合物时有机硅密封胶的性能。结果表明,采用烷氧基硅烷对107硅橡胶进行封端时的较佳条件为:催化剂选择0.01份KOH碱胶,封端剂选择甲基三甲氧基硅烷、乙烯基三甲氧基硅烷或乙烯基三乙氧基硅烷中的一种,反应温度80℃,反应时间60 min。此条件下107硅橡胶的端羟基已基本反应完全,后续制胶过程中无黏度高峰。采用烷氧基封端107硅橡胶作基础聚合物的有机硅密封胶在95℃养护16 h后力学性能保持率较高,贮存稳定性良好,不发生黄变。

Using alkoxysilane to modify α,ω-dihydroxy polydimethylsiloxane(107 silicone rubber) to prepare alkoxy-terminated 107 silicone rubber, the types and content of catalysts for the capping reaction, types of end-capping agent, reaction temperature and time on the effect of end-capping were investigated, and the performance of silicone sealant with alkoxy-terminated 107 silicone rubber used as the base polymer was tested. The results show that the optimal conditions for using alkoxysilane to endcap 107 silicone rubber are as follows: the catalyst is 0.01 part of KOH alkali, and the endcapping agent is methyltrimethoxysilane, vinyltrimethoxysilane or vinyl triethoxysilanes, 80 ℃ for 60 min. Based on the conditions the terminal hydroxyl groups of 107 silicone rubber have basically reacted completely, and there is no viscosity peak in the subsequent process. The silicone sealant with alkoxy-terminated 107 silicone rubber as the base polymer has a high retention rate of mechanical properties, good storage stability, and no yellowing after curing at 95 ℃ for 16 h.