Enzymatic syntheses of unsaturated polyesters based on isosorbide and isomannide

The search for materials produced from renewable sources aiming at the substitution of petroleum-based derivates is an area of intense investigation. In this work, the enzymatic copolymerization of isosorbide or isomannide with diethyl adipate and fractions of different unsaturated diesters (diethyl itaconate, diethyl fumarate, diethyl glutaconate, and diethyl hydromuconate) were examined using CAL-B as catalyst. The polyesters prepared using one-step syntheses were characterized by SEC, NMR, and MALDI-TOF MS. In addition, syntheses with linear diols were carried out in bulk to evaluate the reactivity of cyclic diols in producing unsaturated polyesters using enzymatic catalysis, as well as to evaluate the occurrence of addition side reactions on the double bonds. Isosorbide and isomannide yielded unsaturated polymers with M-w values in the order of 4,000-16,000 when fumarate or glutaconate esters were added in 5 mol % ratio against adipate. In all cases MALDI-TOF confirmed the presence of unsaturated units. Although these polyesters have unreacted double bonds they are prone to crosslinking and ready to further functionalization, like anchoring bioactive molecules. (C) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3881-3891