聚亚苯基硅氧烷交联网络的热性能

Preparation and thermal properties of crosslinked poly(silphenylene-dimethyl siloxane) network

用Si—H/Si—OR缩聚的方法制备了含可交联乙烯基的聚亚苯基硅氧烷-二甲基硅氧烷共聚物(PTMPS-DMS),用硅氢加成、BPO热交联两种方法进行交联得到交联网络,并用热重分析(TG)、300℃恒温热分析和DSC等方法对其热性能进行了研究。结果表明,交联方法对PTMPS-DMS交联网络的热稳定性影响很大,BPO热交联网络的热稳定性远远高于硅氢加成交联网络,两种交联网络在空气中的5%热失重温度分别是480℃和368℃,Tg则没有显著差异,分别是-55℃和-49℃。H2PtCl6能显著降低PTMPS-DMS及其交联网络在空气中的热稳定性。

Poly（silphenylene-dimethyl siloxane）s （PTMPS-DMS） containing crosslinkable vinyl groups were synthesized through the Si--H/Si--OR polycondensation process. The crosslinked PTMPS-DMS networks were prepared by hydrosilation and the BPO thermal crosslink process respectively. TG, DSC and isothermal gravimetric analysis at 300℃ showed that the crosslink process had great impact on the thermal properties of the crosslinked networks. The BPO thermal crosslinked network, which began to degrade at 480℃ in air, possessed much higher thermo-oxidation stability than that crosslinked by the hydrosilation process, which began to degrade at 368℃ in air. The Tgs of these two networks had no significant difference, which were --55℃ and --49℃, respectively. It showed that the catalyst H2PtCl6 greatly decreased the thermo-oxidation stability of the PTMPS-DMS networks.