耐热羟基聚苯硼硅氧烷的制备及表征

Synthesis and characterization of heat-resistant hydroxypolyphenylborosiloxane

为提高羟基聚苯硼硅氧烷的耐热性,以二甲基二氯硅烷(DMDC)与苯硼酸(PBA)为原料,在浓硫酸的催化下合成耐热羟基聚苯硼硅氧烷,研究了单体物质的量比、反应温度对羟基聚苯硼硅氧烷热稳定性的影响。结果表明,当DMDC与PBA物质的量比为10∶1.1、反应温度为120℃时,所得产物质量损失5%时的温度(T_5)为451.2℃、最大分解速率时温度(T_(max))为589.0℃、折射率为1.405 1、相对分子质量为11 920、羟基质量分数为0.260%。利用核磁共振(NMR)、红外光谱(FT-IR)对羟基聚苯硼硅氧烷的结构进行了表征,证实合成了目标产物。四甲氧基硅烷固化的羟基聚苯硼硅氧烷的耐热性提高,T_5为484.0℃。

In order to improve the heat resistance of hydroxypolyphenyl-borosiloxane,it was synthesized by the reaction of PBA and DMDC under the catalysis of sulfuric acid.The effects of monomer molar ratio and reaction temperature on the thermal stability of hydroxypolyphenyl-borosiloxane were investigated.The results showed that when the molar ratio of DMDC to PBA was 10∶1.1 and the reaction temperature was 120 ℃,the hydroxypolyphenyl-borosiloxane's T 5, T max , molecular weight,refractive index,and hydroxyl group content were 451.2 ℃,589.0 ℃,11 920,1.405 1,and 0.260%,respectively.The structure of hydroxypolyphenyl-borosiloxane was characterized and proved by NMR and FT-IR.The heat resistance of boron-silicon rubber obtained by curing the polyborosiloxane with tetramethoxysiloxane was higher than that of polyborosiloxane,and the boron-silicon rubber's T 5 was 584.0 ℃.