PMDA-ODA BASED POLYIMIDE COATINGS VIA A NOVEL CHAIN-EXTENSION REACTION OF OLIGOAMIC ACIDS.

Abstract

The goal of the initial stage of this investigation was to access the relative reactivity of various 'activated' esters as compared to a normal alkyl ester, such as derived from methanol, with an aromatic amine. For this purpose, it was decided to consider a model system based on p-phenoxyaniline and monoalkyl monohydrogen phthalate. The reaction medium was deuterated dimethylsulfoxide to allow rate determinations using **1H-NMR. The chemical shift of the protons associated with the ester groups is sufficiently different from the chemical shift of the corresponding protons of the liberated alcohol to allow unambiguous intensity determinations. In this fashion a series of model esters were run under identical conditions yielding relative reaction rates at 70 degree C.