Biodegradable polymers from renewable sources : new hemicellulose-based hydrogels

Hemicellulose/poly(2-hydroxyethyl methacrylate) (PHEMA)-based hydrogels were prepared by the radical polymerization of HEMA with hemicellulose purposely modified with well-defined amounts of methacrylic functions using a redox initiator system. Oligomeric hydrosoluble hemicelluloses produced from spruce chips were used for modification studies. The chemical modification of hemicellulose was performed with 2-[(1-imidazolyl)formyloxy]ethyl methacrylate as a modifying agent and triethylamine as the catalyst. The kinetics of the modification reaction was monitored by means of 1H NMR spectroscopy. The resulting hydrogels obtained after a 30 min reaction were homogeneous, elastic, and transparent materials.