Preparation Of Surface Protective Films On Flexible Kapton And Space Environmental Adaptability Evaluation

Kapton film coated on the surface of protective films for space environment, such as SiO2 and Al₂O₃, could improve space environmental adaptation of polymer materials. However, due to different mechanical properties and low coefficient of expansion matching of flexible Kapton film with brittle protective film, and strong inert of Kapton surface, the combination between films resulting in poor performance. The protective film is easy to produce cracking, spalling and other defects. In this paper, prepared Kapton/Al₂O₃ nanocomposite film through chemical surface modification-ion exchange, and its formation mechanism and influence factors was studied; and then, MEMO/SiO2 film was coated on the surface of Kapton/Al₂O₃ nanocomposite film using the sol-gel method and investigated its interfacial combination and pace environmental adaptation was investigated by tensile test and pulse laser irradiation. Results showed that:(1) Al₂O₃ particles growed from the interior of Kapton/Al₂O₃ nanocomposite film in the"island growth model". With increase of heat treatment temperature, Al₂O₃ particles become coarse, and Al element content increase. The size, morphology, distribution situation of Al₂O₃ particle took effect on the optical, thermal and mechanical properties of Kapton/Al₂O₃ nanocomposite film significantly.(2) Anion species of metal salt in the ion- exchange reaction made influence on the rate of ion- exchange reaction. Compared with Al(NO3)3 and Al2(SO4)3, AlCl3 was prone to formation of composite layer on the surface of Kapton/Al₂O₃ nanocomposite.(3) MEMO/SiO2 film coated on the surface of pure Kapton film, acid activation of Kapton film and Kapton/Al₂O₃ nanocomposite films, respectively. Tensile test results showed that heat treatment temperature of 300℃to the formation of Kapton/Al₂O₃ nanocomposite film with the best interface combination performance. The process of chemical surface modification-ion exchange was available for improving combination brtween the Kapton film and surface protective film.(4) The Al₂O₃ particles in the modified layer of Kapton/Al₂O₃ nanocomposite film made obstacle for laser irradiation, reducing the laser damage of the substrate material. The film with higher Al content, displayed stronger anti-laser irradiation, so better adaptability to the space environment.