The poly (ester-imide) copolymers were synthesized from N,N`-(4,4`-diphenyl methane) bistrimellitimide (DIDA), dimethyl terephthalate (DMT), ethylene golycol, and 1,3,5-tris-(20hydroxy ethyl) isocyanurate. DIDa monomers were synthesized from solution-condensation polymerization of trimellitic anhydride and methylene dianiline. Compositions of colopymers were controlled by various ratios of DIDa/DMT from 100:0 to 0:100. The synthesized copolymers were cured by reactions with the isocyanate compounds. The structures of DIDa and those copolymers were confirmed by elementary analysis and spectroscopy. From the GPC data, it was found that weight average molecular weights of copolymers were below 3000, and the copolymerization behavior showed 4 or 5 types. The investigation of the thermal stabilities of the cured copolymers were carried out with the data from DSC and TGA analyses by using Freeman-Carroll equation. From the results, it was found that the thermal stabilities of the cured copolymers were increased with increasing DIDa contents.

N,N`-(4,4`-diphenyl methane) bistrimellitimide (DIDa)와 dimethyl terephthalate (DMT), ethylene glycol 및 1,3,5-tris-(2-hydroxy ethyl) isocyanurate를 중합시켜, DIDa/DMT 공중합체를 합성하였다. 이 때 DIDa 단량체는 trimellitic anhydride와 methylene dianiline를 반응시켜 합성하였으며, DIDa와 DMT의 조성비를 100:0으로 변화시켜 공중합체를 합성하였다. 합성된 공중합체와 isocyanate 화합물을 반응시켜 가교시켰다. 단량체 및 공중합체의 구조는 원소분석 및 분광분석을 통하여 확인하였다. GPC 분석 결과 합성된 공중합체는 3000 미만의 중량 평균분자량 값을 나타내었으며, 공중합 유형은 4~5가지를 나타내었다. 공중합체의 조성과 경화제의 종류가 경화물의 열적특성에 미치는 영향을 DSC 및 TGA를 통하여 고찰하였으며, 이 때, Freeman-Carroll식을 이용하여 poly(ester-imide) 경화물의 열안정성을 고찰하였다. 경화물의 열안정성은 DIDa의 함량이 증가할수록 증가하였다.