Hybrid block copolymers incorporating oligosasaccharides and D synthetic blocks grown by controlled radical polymerization

Hybrid block copolymers incorporating a naturally occuring oligosaccharide and a vinylic block were synthezized by chemical modification of the anomeric chain-end of the oligosaccharide with a purposely designed coupling agent, followed by controlled radical polymerization (CRP). In this way, a series of dextran-b-polystyrene block copolymers were obtained using atom transfer radical polymerization (ATRP) as the CRP method. In this case, protection of the OH groups of dextran was required. The resulting diblocks were found to self-assemble into various morphologies (e.g. spherical micelles or vesicles) depending on the PS content. Secondly, xylo-oligosaccharides obtained by controlled enzymatic degradation of Tamarind kern powder were subsequently modified by a xanthate moiety without protection of the OH groups for further polymerization of acrylamide (Am) by MADIX. Well defined Xyloglucan-b-PAm block copolymers could be thus obtained.