Nanoreinforced biocompatible hydrogels from wood hemicelluloses and cellulose whiskers

Nanoreinforced hydrogels with a unique network structure were prepared from wood cellulose whiskers coated with chemically modified wood hemicelluloses. The hemicelluloses were modified with 2-hydroxyethylmethacrylate prior to adsorption onto the cellulose whiskers in aqueous medium. Synthesis of the hydrogels was accomplished by in situ radical polymerization of the methacrylic groups of the adsorbed coating to form a network of poly(2-hydroxyethylmethacrylate) (PHEMA) matrix reinforced with cellulose whiskers. The mechanical, swelling and viscoelastic properties, of water-swollen hydrogels were investigated. Results indicated that the number of effective crosslinks between polymer chains and the average chain length between crosslinking points was significantly different from PHEMA hydrogels that had been crosslinked by a conventional chemical method, using a cross-linking agent. The resulting hydrogels had enhanced toughness, increased viscoelasticity, and improved recovery behavior. With respect to the mechanical and swelling properties, it can be hypothesized that these nanoreinforced PHEMA hydrogels have potential for use in load-bearing biomedical applications such as articular cartilage replacement.