Synthesis and characterization of new functional polymers by polymer-analog reactions on EVOH copolymer

Polymers carrying different organic functional groups (carboxylic acids, tertiary amines, nitriles) were successfully synthesized from poly[(ethylene)-co-(vinyl alcohol)] (EVOH) in two steps. The first step involves acylation of hydroxyl functions of EVOH by phthalic anhydride. Under specific experimental conditions, the substitution may become nearly quantitative. In a second step, alkylation of the so-obtained carboxylic salts is realized in situ using methyliodide, 2-chloroethyl piperidine or chloroacetonitrile, for example. Degrees of substitution (DS) are easily determined by titration of carboxylic functional groups after, respectively, the first and the second steps. Final functional polymers were characterized by IR spectroscopy and 1H and 13C Nuclear Magnetic Resonance. Their thermal properties were determined by differential scanning calorimetry and thermogravimetric analysis. Experimental protocols have been established for the transformation of EVOH into polymers bearing new groups such as carboxylic acids, tertiary amines or nitriles through a one-pot procedure from EVOH.