Swelling of cellulosic gels

Abstract

SYNOPSISThe swelling behavior of a tightly cross-linked cellulose gel has been studied in various polar solvents as a function of temperature. Pronounced second-order transitions were observed at about 25 and 6 0 T , which may correspond to those previously reported in the literature dealing with cellulosic fibers. The transitions are attributed to changes in hydrogen bonding in the system.With the carboxymethyl and dicarboxymethyl derivatives of the cellulose gel, sharp second-order transitions were found at about 25 and 50"C, characterizing interactions involving carboxyl groups. The solvent dependence of the swelling behavior is pronounced.No temperature dependence of swelling was observed with acetylated, methylated,and trimethylsilylated forms of the gel, in which systems hydrogen bonding has been effectively eliminated. 261

Cellulose swelling by protic solvents: which properties of the biopolymer and the solvent matter?

“…Swelling of cellulose and wood by organic solvents has been correlated with their V S and Hildebrand's or Hansen's solubility parameters (Barton 1991;Grulke 1989;Hansen 2004). The fact that some swelling data of cellulose and wood did not correlate with Hildebrand's solubility parameter, d Hildebrand , and that the latter may be split into three components, namely d D (van der Waals dispersion forces), d H (hydrogenbonding), and d P (Keesom's dipole interactions) prompted some authors to use the latter quantities, in addition to V S , in order to correlate swelling with the molecular properties of the solvent (Chitumbo et al 1974;Mantanis et al 1994a;Mantanis et al 1994b;Mantanis et al 1995;Philipp et al 1973;Robertson 1970;Thode and Guide 1959). A different approach has been to substitute d H , with Gutmann's acceptor (AN) and donor (DN) numbers of the solvent (Gutmann 1978).…”

CHAPTER 9. Ball-milling Promoted Chemical Bonding between Cellulose and Plastics

“…Such aggregates cannot be dispersed into primary particles even by an ultrasonic treatment, but can with dimethyl sulfoxide, which causes cellulose to swell by cleavage of hydrogen bonds between molecular chains in it. 18 This suggests strongly that primary particles of cellulose with a certain amount of water aggregate extensively by formation of hydrogen bonds between them, with the aid of water molecules.…”

4. Cellulose

“…They are only included in the structure, and result in a swelling independently of temperature (Richter et al 1957;Chitumbo, Brown 1974) (Fig. But other solvents apart from water can also be adsorbed and linked by H-bonds, e.g.…”