Effect of imidization temperature and spinning condition on structure of polyimide film derived from cyclobutanedianhydride and 2,2-bis(4-aminophenoxyphenyl)propane

Abstract

The polyimide derived From cyclobutanedianhydride and 2,2-bis(4-aminophenoxyphenyl)propane (CBDA-BAPP) is one of the typical materials for liquid crystal alignment layer in liquid crystal display (LCD). The effects of imidization temperature and spinning condition on degree of imidization, and in-plane orientation of the CBDA-BAPP film were studied. The imidization temperature at 200 degrees C was found to be insufficient for complete imidization of the amic acid group. The in-plane orientations of the CBDA-BAPP films imidized at 200 degrees C and 250 degrees C were similar to each other, although they were higher than that of the film imidized at 150 degrees C. With increasing the spinning rate and decreasing the solution concentration in the spin-casting procedure, the degree of imidization was decreased, together with the increasing in-plane orientation which would be mainly governed by chain immobilization rate over the chain stiffness.