Characterization of Colorless and Transparent Polyimide Films Synthesized with Various Amine Monomers

Abstract

A series of poly (amic acid)s(PAAs) was prepared by reacting 4.4'-(4.4'-isopropylidene-diphenoxy)bis(phthalic anhydride) (BPADA) as the anhydride monomer and 2,2'-bis(trifluoromethyl) benzidine (TFB), bis (3 aminophenyDsulfone (AIDS), 4,4'-methylenebis-(2-methylcyclohexylamine) (MMCA), or his [4 (3 aminophenoxy) phenyl] sulfone (BAPS) as the amine monomer with 5 mol% melamine in N,N-dimethylacetamide (DMAc). Colorless and transparent polyimide (PI) films were obtained by casting the PAAs at various heat treatment temperatures. The thermo mechanical properties and optical transparency of the PI films were investigated. The thermal properties of the PI films were examined using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis (TMA), and their optical transparency were measured by spectrophotometry. The coefficient of thermal expansion (CTE) and yellow index (YI) values of all samples were in the range of 46.89-64.24 ppm/degrees C and < 3.0. respectively.