不同硝基苯基POSS的合成及热性能研究

Synthesis and Thermal Properties of the Different Nitrophenylsilsesquioxanes

以八苯基笼型低聚倍半硅氧烷(OPS)和十二苯基笼型低聚倍半硅氧烷(DPS)为原料,经发烟硝酸和发烟硝酸/浓硫酸的混合酸硝化反应,分别合成了八硝基苯基笼型低聚倍半硅氧烷(ONPS),十二硝基苯基笼型低聚倍半硅氧烷(DNPS),十六硝基八苯基笼型低聚倍半硅氧烷(HDNPS)。利用傅里叶红外光谱、核磁共振光谱、XRD分析测试手段对其结构进行了表征。重点考察了笼子体积和硝基取代数对化合物热稳定性的影响,经TGA测试表明:三者质量损失为5%时的温度分别为349℃、292℃、187℃,最大热分解速度对应的温度分别是430℃、428℃、410℃,在1 190℃处,三者的残留质量分数分别是53.4%、50.25%、36.69%。三者都具有良好的热稳定性,其中以硝基取代数最少和笼子体积最小的ONPS热稳定最佳。

Octanitrophenylsilsesquioxane （ ONPS）, dodecanitrophenylsilsesquioxane （DNPS） and hexa- decanitrophenylsilsesquioxane （HDNPS） were synthesized by nitration of octaphenylsilsesquioxane （OPS） and dodecaphenylsilsesquioxane （DPS） in the fuming nitric acid or fuming nitric acid/sulfuric acid. The structures were characterized by ~F - IR, NMR and XRD. The effects of the cage structure and the number of nitro groups on the thermal stability of the chemicals were investigated. Thermal gravimetric analysis （TGA） showed that they all had good thermal stability, with the maximum thermal stability of ONPS （ Tds = 349 ℃, 292℃, 187℃ ） at a mass loss of 5%, and the maximum thermal decomposition temperature was 430 ℃, 428 ℃ and 410℃, respectively. The residual mass fraction of ONPS, DPNS and HDNPS at 1190 ℃ was 53. % , 50. 25% , 36.69%, respectively. All three materials had good thermal stability, among which the thermal stability of ONPS with the least nitro replaced and the smallest volume of cage was the best.