CURING STUDIES OF NEW POLYIMIDE MODEL COMPOUNDS WITH MOLECULAR-WEIGHTS OF ABOUT 1000 G MOL/

Two new polyimide model compounds with molecular weights of similar to 1000 g/mol have been synthesized. While the amino terminated compound , ophenoxy-4'-phenyl)-pyromellitimido]diphenylether, O(PO)(2), undergo es a branching or crosslinking side reaction, the corresponding anhydr ide terminated oligomer nyl)phthal-imido)phenoxy-4'-phenyl]pyromelliti mide dianhydride, P(OP)(2), loses its anhydride functionality complete ly upon thermal treatment. In the case of O(PO)(2), the formed C=N spe cies can be detected with Raman spectroscopy rather than FT-IR spectro scopy because of its low molecular absorptivity in the infrared region . The formation of imine bonds caused by the attack of terminal amino groups on the imide carbonyl group is evident by the appearance of pea ks at about 1665 cm(-1) in the Raman spectra. The same behavior can be observed in bulky polyimides blended with an increasing amount of O(P O)(2) upon curing.