聚酰亚胺/SiO_2纳米复合抗原子氧气凝胶的合成与性能

以3,3′,4,4′-联苯四酸二酐(sBPDA)和2,2′-二甲基-4,4′-二氨基联苯胺(DMBZ)为聚合单体,八(氨基苯基)聚倍半硅氧烷(OAPS)为交联剂,SiO2纳米粒子为填料,采用超临界二氧化碳干燥工艺制备了一系列聚酰亚胺(PI)/SiO2纳米复合气凝胶(CPIA-SiO2-0~CPIA-SiO2-7)。研究表明:SiO2纳米粒子的引入对PI气凝胶的耐热性能未产生显著的影响。然而,随着SiO2纳米粒子含量的增加,PI气凝胶的孔隙率从89.6%逐渐降低至79.4%,BET表面积也随之从425.5m2/g降低至380.2m2/g,纳米泡孔孔径分布呈现出变宽的趋势。SiO2的引入显著提高了PI气凝胶的抗原子氧侵蚀能力,含量为7%(质量分数,下同)的PI/SiO2复合气凝胶CPIA-SiO2-7的原子氧侵蚀率(2.6%)仅为不含SiO2气凝胶CPIA-SiO2-0的原子氧侵蚀率(12.3%)的1/5左右。

Synthesis and Properties of Atomic-oxygen Resistant Polyimide-SiO2 Nanocomposite Aerogels

A series of polyimide (PI)-SiO2 nanocomposite aerogels (CPIA-SiO2-0-CPIA-SiO2-7)were successfully prepared via the supercritical carbon dioxide drying process of the nanocomposite PI wet gels derived from 3,3′,4,4′-biphenylene tetracarboxylic dianhydride (BPDA)and 2,2′-dimethylbenzi-dine (DMBZ)with octa(aminophenyl)silsesquioxane (OAPS)as the end-capper,and nano-sized silica particles as the filler.The results indicate that the introduction of nanoscale silica particles have not apparently affected the thermal resistance of the obtained aerogels.However,with the increase of SiO2 loading in the aerogels,the porosity from 89.6% to 79.4% and the Branuaer-Emmet-Teller (BET)surface areas of the composite aerogels decrease from 425.5m2/g to 380.2m2/g,meanwhile, the pore size distribution widens gradually.At last,the atomic-oxygen resistance of the PI-SiO2 aero-gels is greatly improved by introduction of nanoscale SiO2 fillers.The atomic-oxygen erosion ratio (2.6%)of CPIA-SiO2-7 with 7% SiO2 loading is only 1/5 that(12.3%)of the pristine CPIA aerogel (CPIA-SiO2-0).