Papers by Keyword: Polyimide-Silica

Abstract: To improve AO resistance of polyimide, a type of polyimide/silica (PI/SiO2) hybrid film was prepared by the sol-gel process. The coupling agent p-aminophenyltrimeth- oxysilane (APTMOS) was chosen to enhance the compatibility between the polyimide (PI) and silica (SiO2). AO resistance of the PI/SiO2 hybrid films were tested in the ground-based simulation AO facility. The erosion yield of the films was 4.7×10-26 cm3/atom, decreased by two orders of magnitude compared with the value of 3.0×10-24 cm3/atom of the polyimide film. Results from FTIR, XPS, AFM on AO treated polyimide/silica hybrid films indicate the formation of a passivating inorganic SiO2 layer. The layer significantly retards the penetration of oxygen atoms, preventing further degradation of the polymer in the bulk. The addition of SiO2 in polyimide does not significantly alter the optical properties of polyimide during AO exposure.

Abstract: Polyimide (PI)-based nanocomposites were prepared by the in-situ generation of organic silica nano-particles through a sol-gel process, combined with spin coating and multi-step curing process. In this study, silica nano-particles were introduced into the PI matrix to promote its thermal properties. Nanometer-scale composites were successfully obtained from poly(amic acid) (PAA) mixture loaded with silica. 3,3’,4,4’- Biphenyl tetracarboxylic dianhydride (BPDA) and p-phenylenediamine (p-PDA) were employed to synthesize the PAA precursor. The hybrid thin film was prepared from aminoalkoxysilane-capped PAA and tetraethoxysilane (TEOS). In this work, we investigated the effect of coupling agent, 3-aminopropyltriethoxysilane (APrTEOS). The TGA results indicate that the thermal stability of the nanocomposites can be enhanced as silica content increases. Without the incorporation of APrTEOS, less improvement can be achieved.