Synthesis of Chitosan-graft-Poly(vinyl ether) as a Thermoresponsive Water-Soluble Chitosan

Abstract

The successful grafting of controlled-molecular-weight hydrophilic formyl-terminated poly(vinyl ether)s (poly(VE)s) onto chitosan is reported herein. As the chitosan-graft-poly(ethyl vinyl ether) [poly(EVE)] was not completely soluble in the NMR solvent, the degree of substitution could not be determined by ¹H NMR spectroscopy. In contrast, synthesis of the chitosan-graft-poly(ethoxyethyl vinyl ether) [poly(EEVE)] was less efficient (degree of substitution being 0.3), but the obtained graft copolymers were soluble in water, and the lower critical solution temperature was determined to be ~35 ̊C. Thus, functional chitosan materials were successfully developed by grafting thermoresponsive formyl-terminated poly(EEVE) onto chitosan.