Synthesis and properties of a high‐molecular‐weight poly(amic acid) and polyimide based on 2,2‐bis(3‐amino‐4‐hydroxyphenyl)hexafluoropropane

Abstract

AbstractThe feasibility of using the conventional two‐step procedure involving the thermal imidization of a high‐molecular‐weight poly(amic acid) (PAA) for the preparation of self‐supporting polyimide (PI) films was studied. Synthesized PAA and PI were analyzed with respect to their molecular weights, chemical structures, and mechanical and thermal properties. The results showed that a high‐molecular‐weight PAA was successfully synthesized from 2,2‐bis(3‐amino‐4‐hydroxyphenyl)hexafluoropropane with 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride. The high intrinsic viscosity of PAA was 1.5 dL/g. Self‐supporting PI films were successfully prepared by the thermal imidization of PAA and reached maximum tensile strength, tensile modulus, and elongation at break values of 103 MPa, 2.2 GPa, and 10.7%, respectively. The PI films were stable to 426–483°C (the 5% weight loss temperature) and had a glass transition at 271–283°C. All these results indicate that the conventional two‐step procedure involving thermal imidization is a promising method for preparing self‐supporting PI films with reasonable levels of mechanical and thermal properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011