Novel glycopolymers containing aminosaccharide pendant groups by chemical modification of ethylene-vinyl alcohol copolymers

Ethylene-vinyl alcohol, EVOH, copolymers with two different vinyl alcohol compositions have been modified to incorporate different reactive functional groups by using phthalic anhydride, chloroacetyl chloride and 4-nitrophenyl chloroformate. Moreover, coupling reactions between EVOH copolymers functionalized with 4-nitrophenyl carbonate groups and three aminosaccharides (d-(+)-glucosamine, d-(+)-galactosamine and d-(+)-mannosamine) have been carried out in dimethyl sulfoxide at 70 °C. The structure of the resulting functionalized copolymers and new glycopolymers was confirmed by FTIR, 1H and 13C NMR. In addition, the thermal characterization of glycopolymers has been performed by DSC. A unique thermal transition, ascribed to the glass transition, is observed in both glycopolymer series. The semicrystalline character of the initial EVOH copolymers is vanished and complete amorphous polymeric materials are obtained since the resulting glycopolymers present relatively long and bulky pendant chains impossible to be included in the EVOH crystallites.