ELASTICITY AND SWELLING BEHAVIOR OF CHEMICALLY CROSS-LINKED CELLULOSE ETHERS IN AQUEOUS SYSTEMS

The mechanical properties and the swelling behaviour of hydrogels based on sodium carboxymethylcellulose and hydroxyethylcellulose were investigated. The gels were prepared by crosslinking the cellulose ethers via divinylsulphone in alkaline solution. The outstanding feature of such materials is their increase of modulus with increasing swelling, which starts already at rather low degrees of swelling (around 10). In this respect, the cellulosic gels are superior to the hydrogels based on acrylic polyelectrolytes currently in use for superabsorbent products. The reason for these properties is seen in the large persistence length of the cellulose backbone, giving rise to non-Gaussian behaviour at much lower chain deformations than with more flexible polymers. © 1990.