梯形聚苯基倍半硅氧烷的合成及对RTV硅橡胶性能的影响

Synthesis of ladder⁃like polyphenylsilsesquioxane and its effect on the properties of room temperature vulcanized(RTV)silicone rubber

选取苯基三甲氧基硅烷(PTMS)作为原料,在碱性条件下通过水解缩聚反应合成了梯形聚苯基倍半硅氧烷(LPPSQ),将其作为交联剂加入生胶中,交联固化后得到了LPPSQ改性的室温硫化(RTV)硅橡胶。通过红外光谱,固态核磁硅谱以及X射线衍射图谱对产物进行表征,结果表明成功合成了LPPSQ。探究了LPPSQ的加入对RTV硅橡胶性能的影响,结果表明LPPSQ的加入能显著提升RTV硅橡胶的热稳定性能和力学性能。相比于传统RTV硅橡胶,以LPPSQ为交联剂的RTV硅橡胶断裂伸长率达到358%,提高了2倍多,韧性也得到了显著增强。此外,在热稳定性能方面,LPPSQ的加入也大幅提高了RTV硅橡胶的T10%(硅橡胶质量损失10%的温度)的Tmax(硅橡胶最大热失重速率对应的温度),分别提高了138.2℃和224.1℃。

Ladder-like polyphenylsilsesquioxane(LPPSQ)has been synthesized by a hydrolytic polycondensation reaction under alkaline conditions using phenyltrimethoxysilane(PTMS)as the raw material.LPPSQ modified room temperature vulcanized(RTV)silicone rubber was obtained after cross-linking and curing.The product was characterized by Fourier transform infrared spectroscopy,solid-state silicon-29 nuclear magnetic resonance spec-troscopy,and powder X-ray diffraction.The results showed that LPPSQ was synthesized successfully.The effect of LPPSQ on the properties of RTV silicone rubber was studied.It was found that LPPSQ can significantly improve the thermal stability and mechanical properties of RTV silicone rubber.Compared with traditional RTV silicone rubber,the elongation at break of RTV silicone rubber using LPPSQ as a crosslinking agent is more than two times higher,reaching 358%,and the toughness is significantly enhanced.In addition,in terms of thermal stability,LPPSQ also significantly increased the T10%and Tmax of RTV silicone rubber by 138.2℃and 224.1℃,respec-tively.