A series of polyimide was prepared by reacting 4,4`-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) as the anhydride monomer and 2,2`-bis(trifluoromethyl)benzidine (TFB), 2,2`-bis(3-aminophenyl)hexafluoropropane (BAFP), 2,2`-bis(3- amino- 4-methylphenyl) hexafluoropropane (BAMF), bis(3-aminophenyl)sulfone (APS), p-xylyenediamine (p-XDA), or m-xylyenediamine (m-XDA) as the amine monomer in N,N-dimethylacetamide (DMAc). Colorless and transparent polyimide (PI) films were obtained by casting the poly (amic acid)s (PAAs) solution at various heat treatment temperatures. The thermal properties of the PI films were examined using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis (TMA) and the mechanical properties were investigated using universal tensile machine (UTM), Their optical transparencies were also investigated using ultraviolet-visible (UV-vis.) spectrophotometry and colorimetry, The yellow index (YI) and coefficient of thermal expansion (CTE) values of all PIs were in the range 0.98∼2.76 and 25.73∼55.23ppm /℃, respectively.

무수물인 4,4`-(hexafluoroisopropylidene)diphthalic anhydride (6FDA)에 2,2`-bis(trifluoromethyl)benzidine (TFB), 2,2`-bis(3- aminophenyl)hexafluoropropane (BAFP), 2,2`-bis(3-amino-4-methylphenyl)hexafluoropropane (BAMF), bis(3-aminophenyl) sulfone (APS), p-xylyenediamine (p-XDA), 및 m-xylyenediamine (m-XDA) 등 6종류의 각각 다른 아민 단량체를 이용하여 폴리이미드(PI) 필름을 제조하였다. 얻어진 무색 투명한 PI필름은 무수물과 아민을 반응시켜 폴리아믹산(PAA)을 합성 한 후, 용액 캐스팅에 의한 열처리 과정을 통해 얻었다. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermo-mechanical analysis (TMA)를 이용하여 열적 성질을 측정하였고, universal tensile machine (UTM)을 이용하여 기계적 성질을 조사하였으며, 자외선/가시광선 분광광도계(UV-vis.)와 색차계를 이용하여 광학적 성질을 각각 확인하였다. 제조된 모든 필름들은 무색 투명하여 0.98∼2.76 사이의 노란색 지수를 보였으며, 25.73∼55.23 ppm/℃ 사이의 열 팽창 계수를 나타냈다.