Effect of Dimethyl Sulfoxide on Synthesis of Thermoplastic Cellulose-Graft-Poly(L-lactide) Copolymer Using Ionic Liquid as Reaction Media

In this study, ring-opening graft polymerization of l-lactide onto cellulose was carried out homogeneously in ionic liquid (IL)/dimethyl sulfoxide (DMSO) co-solvent as a reaction media. Through the effective control of high viscosity and steric hindrance caused by the interaction between the IL and the hydroxyl group of cellulose by adding DMSO as a co-solvent, cellulose-graft-poly(l-lactide) (Cell-g-PLLA) copolymer with higher substitution efficiency was successfully prepared, at relatively low concentration of l-lactide. The maximum values of molar substitution, degree of lactyl substitution, and degree of polymerization of poly(l-lactide) in the copolymer were 3.76, 1.74, and 2.16, respectively, determined by H-1-NMR. The prepared cell-g-PLLA copolymers showed thermal plasticization with a glass transition temperature of 155 degrees C. In addition, the thermal processibility could be improved as the amount of grafted PLLA in the copolymer increased. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41331.