폴리이미드 공중합체의 합성과 그 특성에 관한 연구(I) -3,4-디아미노디페닐에테르와 파라페닐렌디아민으로 부터 합성한 폴리피로멜리트이이드 공중합체-

Syntheses and Properties of Aromatic Copolymides(I) -Copolypyromllitimides from 3,4합-Diaminodiphenyl Ether and p-Phenylenediamine-

Aromatic copolyamic acids were prepared by low temperature solution polymerization from pyromellitic dianhydride and diamines (3,4'-diaminodiphenyl ether/p-phenylenediamine). The resulting polyamic acids were converted to polyimides by means of thermal cyclodehydration. These copolymers were identified by infrared spectroscopy and their properties were investigated. The thermal stability of copolymides was improved as the mole ratio of p-phenylenediamine in copolyimide chain increased. This result shows that their thermal stabilities are related to the rigidity of polymer chain and the interaction between the polymer chains. Copolyamic acids having amide and carboxylic acid groups in polymer chain were quite soluble in aprotic polar solvents such as DMF, DMAC and DMSO. But the copolyimides were insoluble in conventional solvents. All copolyimides showed an increase in density upon cyclodehydration of copolyamic acids perhaps because of the reduction of molar volume of polymers.