폴리이미드의 구조에 따른 방향족 PBI / PI 블렌드의 상용성 및 상호작용의 세기 = Miscibility and Specific Intermolecular Interaction Strength of PBI / PI Blends Depending on Polyimide Structures

다국어 초록 (Multilingual Abstract)

Four kinds of polyamicacids(PAAs) were prepared by the condensation reaction of four diamines with different linkages, 3,3`-diamino-diphenyl sulfone(3,3`-DDSO₂), 4,4`-diaminodiphenyl sulfone(4,4`-DDSO₂), 4,4`-methylene dianiline (4,4`-MDA), and 4,4`-oxydianiline(4,4`-ODA), and dianhydride, 3,3`,4,4`-benzophenone tetracarboxylic dianhydride(BTDA) using the solvent, dimethylacetamide(DMAc). These four PAAs were blended with poly[2,2-(m-phenylene)-5,5`-bibenzimidazole](PBI) from the solution blending. Then called as Blend- I, II, III, and IV, respectively. Cast films or precipitated powders of the PBI/PAA blends were cured at a higher temperature than expected Tg to transform into PBI/PIs blends. Misability, specific intermolecular interaction for miscibility and their relative strength as a function of polyimide chemical structure with different four diamines in the PBI/PI systems were investigated. Four blends used in this study were all miscible, and the specific intermolecular interactions existing in these blends was thought to be the hydrogen bonding between the N-H of PBI and the C=O of PIs. The hydrogen bonding in the blends were shown to be stronger in the Blend-III and IV than in the Blend-I and II. It is speculated that the differences of hydrogen bonding strength of PBI/PI blends are dependent upon chemical structures of PIs, that is, PIs consisting of SO₂ group have a weaker hydrogen booding strength than those of O or CH₂ group because the former has a larger spacer than the latter.