Poly(amic acid)(PAA) was prepared by reaction of bicyclo(2,2,2)oct-7-ene-2,3,5,6-tetracarboxylicdianhydride(BTDA) containing double bond for crosslinking and bis[4-(3-aminophenoxy) phenyl] sulfone(BAPS) in N,N-dimethylacetamide(DMAc). The cast film of PAA was heat-treated at different temperatures to create polyimide(PI) films. With increasing thermal crosslinking temperatures from 250 to 350 ℃, the thermo-mechanical properties, degree of crosslinking, and optical transparency of the cross-linked PI were investigated. The maximum enhancement in the thermo-mechanical properties was observed at a heat treatment condition of 350 ℃. However, the optical transparency was found to be optimal for 250 ℃ heat treatment. The degree of crosslinking in NMR was determined to be 85% to 93% with increasing annealing temperature conditions from 250 to 350 ℃.

폴리아믹산(PAA)은 가교가 가능한 2중 결합을 갖는 bicyclo(2,2,2)oct-7-ene-2,3,5,6-tetracarboxylicdianhydride(BTDA)와 bis[4-(3-aminophenoxy)phenyl] sulfone(BAPS)을 N,N-dimethylacetamide(DMAc) 용매에서 반응하여 얻어졌으며, 폴리이미드(PI) 필름은 PAA를 캐스팅하여 각각 다른 반응 온도에서 열처리를 통해 얻었다. 가교 온도를 250∼350 ℃까지 증가하여 얻은 가교된 PI의 열적-기계적 성질, 가교도, 광학적 특성을 열처리 온도에 따라 조사하였다. 열적-기계적 성질은 350 ℃에서 열처리되었을 때 최대 값을 나타냈으며, 광학적 특성은 250 ℃에서 열처리된 필름이 가장 우수한 광학특성을 보였다. 250∼350 ℃까지 열처리에 따른 가교도는 NMR 상에서 85∼93%를 나타냈다.

Keywords: colorless PI; crosslinkable monomer; films.