杂化聚酰亚胺的制备及其耐原子氧剥蚀性能

低地球轨道环境中的原子氧会剥蚀航天器表面材料，影响其性能和寿命，因此在使用时需要选用合适的手段来进行原子氧防护。采用溶胶-凝胶法，利用正硅酸乙酯在树脂体系中的水解-缩合反应，在基体中原位生成无机相而获得杂化聚酰亚胺。在原子氧效应地面模拟设备中，对杂化聚酰亚胺试样开展了性能评估试验，总结了试验前后试样的质量、表面形貌和表面成分的变化特点，并分析了材料耐剥蚀性能与正硅酸乙酯添加量的关系、杂化材料的耐剥蚀机理。结果表明，杂化聚酰亚胺的耐原子氧性能优于原树脂，其原子氧试验质量损失仅为原树脂的31。6% ~14。8%。分析认为，溶胶-凝胶过程中在树脂基体中生成的有机含硅结构和无机SiO₂，以及原子氧作用下杂化材料表面生成的SiO₂保护层，是杂化材料耐原子氧剥蚀性能提高的原因。

Preparation and atomic oxygen resistance of hybrid polyimide

Atomic oxygen (AO), the predominant components and the most active species in low earth orbit atmosphere, can cause the erosion and degradation of spacecraft materials. To improve the AO-resistance of the resin, Tetraethyl orthosilicate (TEOS) was added into the polyimide (PI) matrix, and then the inorganic phases of SiO₂ were generated in-situ using sol-gel method and the SiO₂/PI hybrid materials were obtained. The ground-based simulation experiments were carried out to evaluate the AO-resistance of the SiO₂/PI hybrid materials. The mass, surface morphology and surface composition of the samples were compared before and after the AO experiments. The effects of the adding amount of TEOS and the improving mechanism of the AO-resistance were analyzed. Results show that the AO-resistance of hybrid materials is better than that of the pristine resin and the relative mass loss is 31.6% ~14.8%. There are two essential reasons of the AO-resistance of the hybrid material that the silicones and silica are generated in the resin matrix during sol-gel process and the silica protective coating is formed on the sample surface in AO environment.