Polyimides having pendant hydroxy and acetoxy groups. I. Synthesis of polyimides from pyromellitimide and bisepoxides

Abstract

AbstractPolyimides having pendant hydroxy groups were prepared by addition of pyromellitimide with bisepoxides. Tertiary amines and quaternary ammonium halides were effective as a catalyst. The polyimides were soluble in dichloroacetic acid and had inherent viscosities in the range 0.16–0.19 dl/g. Thermogravimetric analysis showed that a rapid weight loss of the polymers occurred at about 400°C. The pendant hydroxy groups were easily acetylated by treating the polymers with a mixture of acetic anhydride and pyridine. The acetylated polyimides were soluble in dimethylformamide, dimethylacetamide, and dioxane and melted at 120–150°C.