Enzyme catalysed modification of synthetic polymers

Abstract

The first example of an enzyme catalysed modification of the backbone of a synthetic polymer is described. An immobilised lipase from Candida antarctica (Novozym 435) catalyses the selective epoxidation of polybutadiene in organic solvents in the presence of hydrogen peroxide and catalytic quantities of acetic acid. The cis and trans alkene bonds of the backbone are epoxidised in yields of up to 60% whilst the pendent vinyl groups are untouched. The effect of varying a number of reaction parameters suggests that higher yields of epoxide could not be obtained because of the conformational properties of the partially epoxidised polymer. Application of this same enzymatic process to the Baeyer–Villiger reactions of poly(phenyl vinyl ketone) and poly(methyl vinyl ketone) were unsuccessful. The lack of reactivity was found to be a property of the polymers rather than of the enzymatic system.