2016 Volume 29 Issue 2 Pages 237-242
An alicyclic tetracrboxylic dianhydride having cyclopentanone bis-spironorbornane structure (CpODA) was polycondensated with aromatic diamines in the various kinds of solvents. The poly(amic acid)s were imidized by a chemical and a thermal methods. In chemical imidization of poly(amic acid) derived from CpODA and 2,2'-dimethyl-1,1'-biphenyl-4,4'-diamine in N,N-dimethylacetamide and γ-butyrolactone the polyimides precipitated as the reaction proceeded. The precipitates, however, were soluble in hologenated solvents such as CHCl3. The solution processable polyimides formed colorless and flexible films after cast then dried. All the polyimide films possessed excellent thermal stability and had glass transition temperatures over 322 oC. The coefficient of thermal expansion (CTE) values of chemically imidized polyimide films were lower than those of thermally imidized ones and there was only a small difference in CTE among polyimide films prepared in different polymerization solvents. The polyimide films exhibited λ cut-off shorter than 298 nm, and the values of transparency in the visible region were over 84% and highly colorless.
