Preparation and Application of Alkoxy-Terminated 107 Silicone Rubber

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 based 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 16h.