SWELLING OF CELLULOSIC GELS.

The swelling behavior of a tightly crosslinked cellulose gel has been studied in various polar solvents as a function of temperature. Pronounced second-order transitions were observed at about 25 and 60C, 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 50C, 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.