Relaxational motion and ice formation of water adsorbed to cellulose

Cellulose, the most abundant structural polymer in nature is strongly hydrophilic. Adsorbed water molecules are found to relax on the time scale of picoseconds far below the melting temperature of bulk water. The relaxation times are considerably longer than in bulk supercooled water. The liquid component is stable towards crystallization. With decreasing temperature it gradually freezes into a distinct amorphous polymorph of water which bears resemblance to low-density amorphous ice

Dynamics of water adsorbed to cellulose

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Thermal Characterization of Chitosan-Grafted Membranes to be Used as Wound Dressings

Six different membranes previously prepared by the authors by graft copolymerization of acrylic acid (AA) and 2-hydroxyethylmethacrylate (HEMA) onto chitosan were characterized. The graft copolymerization of the vinyl monomers onto chitosan was confirmed by FTIR and DMTA. The chitosan used was also characterized by DMTA, which allowed addressing some questions related to the typical thermal transitions of this biopolymer. The swelling capacity of the membranes was also determined. The chitosan-graft-AA-graft-HEMA with an equimolar ratio of HEMA and AA kept good swelling capacity without compromising its physical stability, which suggests it to be the best matrix for drug delivery systems.http://www.informaworld.com/10.1080/0732830060073408