| Abstract: | The interface reactions of 3-aminopropyltriethoxysilane treated surfaces, with the polyamic acid/polyimide resin formed from pyromellitic dianhydride and oxydianiline, were defined in bulk reactant systems and by FTIR analysis on the surface layers of germanium internal reflection plates. Adhesion between these interfacial layers is the result of chemical bonding, which proceeds through initial carboxylate salt formation between the amino function of the silylated surface and the car-boxylic acid present in the polyamic acid. Heating results in dehydration and amide formation, which is followed by preferential incorporation of the alkyl, surface-bound amine (stronger base), over the aromatic polymer amine, in an imide linkage. Aromatic imides formed before or during thermal curing may also be preferentially opened in a modified Ing-Manske reaction and reclosed to the more stable surface-bound alkylimide. Apparently polymer scission at the aromatic amide linkages occurs in this adhesion process, preferentially bonding surface-bound alkyl amines to one end of a shortened polymer chain. |
