HYDROLYSIS OF POLYAMIC ACIDS WITH MICRO-MOISTURE

It is not always easy to keep moisture away during film formation from dope of polyamic acids. Two kinds of Kapton and Upilex-S types of polyimide were made from dope of polyamic acid; the rates of hydrolysis caused by micro-moisture in these dopes were determined. The relationships for dopes with no water or 1 vol% water were well fitted by an Arrhenius type equation: log[(1/P)-(1/P0)]t(-n) = (A/T) + B. So the apparent activation energy of hydrolysis for no water or 1 vol% water in the two types of dope of polyamic acid is 16 approximately 17 kcal/mol on non-water and 18 approximately 20 kcal/mol on 1 vol% water content. The concentrated dope from which the film were prepared showed Bingham's flow. The viscosity which dopes included no or 1 vol% water was increased with increasing degree of polymerization of polyamic acid.