The synthesis of a novel polymide precursor
Peter Delvigs, Li‐Chen Hsu, T. T. Serafini · NASA Technical Reports Server (NASA) · 1969
A novel blocked polyimide precursor was synthesized by using diethylamine a s the blocking reagent.The structure of the blocked precursor is the bis(N, N-diethylamide) of the polyamic acid derived from pyromellitic dianhydride and 4,4'-diaminodiphenyl ether.The blocked precursor was more resistant to thermal imidization than the cor responding polyamic acid.The weight-average molecular weight of the blocked precur s o r could be increased by solid-state polymerization.However, the molecular weight of the polyamic acid could not be changed from i t s initial value.Furthermore, the blocked precursor was still completely soluble after solid-state polymerization.The solvolytic stability of the blocked precursor in anhydrous N. N-dimethylacetamide was superior to that of the polyamic acid.