ASYMMETRIC AROMATIC POLYIMIDE CHEMISTRY AND NEW GENERATION, HEAT RESISTANT POLYIMIDES (ISASTPI) FOR IKAROS MEMBRANE

摘要

Structure–property relations for isomeric aromatic polyimides containing asymmetric aromaticrnimide structures have been discussed. Asymmetric polyimides such as 2,3,3’,4’-rnbiphenyltetracarboxylic dianhydride (a-BPDA) or 2,3,3’,4’-oxyphthalic dianhydride(a-ODPA)rnwith 4,4’-oxydianiline(4,4’-ODA) exhibited higher T_g than those of symmetric s-BPDA/4,4’-rnODA and a-ODPA/4,4’ODA. Furthermore, these polyimides indicated a large drop in the storagernmodulus, E′ beyond the Tg. Based on these results, novel asymmetric aromatic addition-typernpolyimide resins were developed for composites and heat sealable thermoplastic polyimide filmsrnwith high stability in space. This paper also presents an application of the thin film: the world’srnfirst solar sail membrane, used for “IKAROS”.