CAJ | 학술논문

A novel unsymmetrical dianhydride containing 4-(4-hydroxylphenyl)-2,3-phthalazin-1-one was synthesized in order to improve the solubility of aromatic polyimides according to the principle of designing new monomers.This article reported a series of polyimide random copolymers derived from 4,4′-diamino diphenyl sulfone (DAPS),4,4′-oxyl dianiline (ODA) and the new dianhydride-2-(3,4-dicarboxyl-phenyl)-4-(3′,4′-dicarboxyl-phenyl-oxyl)-phenyl-2,3-phthalazine-1-one dianhydride (DAH4) by“one-step”solution polycondensation in m-cresol with catalystic amount of isoquinoline at 200℃.Some properties of the copolymers were investigated by DSC,TG and mechanical analysis.The result shows that the ηinh of copolymers is between 0.64 to 0.71 dL/g in m-cresol at 25℃,and the Tg of the copolymers are higher than that of pure poliymides containing 4,4′-oxyl dianiline (polymer 5).The relationship between Tg and mole percent of DAPS is not obvious.Degradation temperature for 5% weight loss (Td5) of the copolymers occurs all above 470℃ in air.The mechanical properties of the copolymers are lower owing to introducing sulfone groups into polymer's backbone.In sharp contrast,the copolymers have good solubility and can be easily soluble in 1,1,2,2-tetrachloroethane(TCE),N,N-dimethylacetamide(DMAc),N-methyl-2-pyrrolidinone (NMP),m-cresol and pyridine.Furthermore,the copolymers have better solubility in dimethyl sulfoxide (DMSO) and chloroform than the polyimide derived from DAH4 and ODA.