John Anthony Kreuz

Polyimidizations from acylated diamines and dianhydrides

Abstract Imide ring formation upon heat treatment of diacylated diamines and dianhydrides was shown to be highly efficient. Evidence to support this conclusion was obtained from thermal gravimetric analyses, differential scanning calorimetry and infra-red spectroscopy. Equimolar mixtures of diacylated diamines and dianhydrides form eutectic mixtures, which quantitatively eliminate the corresponding acid to form imides. Besides the possibility of polyimidization, the reaction of acylated amino end-groups with anhydride end-groups was demonstrated to be useful for chain extension by post-heating a lower-molecular-weight polyimide based on pyromellitic dianhydride (PMDA) and 4,4′-aminodiphenyl ether (ODA). Advantages gained by this technique are narrower molecular-weight distributions and higher-solids poly(amic acid) solutions with lower solution viscosities, which allow more facile fabrication into useful articles.