Synthesis Of Cellulose-graft-PLLA Catalyzed By DMAP

According to the concept of green chemistry and sustainable development, a new biodegradable cellulose-graft-poly (L-lactide) was designed and synthesized. In this study, cellulose-graft-poly (L-lactide)(cellulose-g-PLLA) was prepared via ring-opening polymerization (ROP) catalyzed by4-dimethylaminopyridine (DMAP) in an ionic liquid1-allyl-3-methylimidazolium chloride (AmimCl). A chemical modification technical route of natural cellulose in homogeneous environment was provided, and the efficient catalysis mechanism of DMAP in the ring-opening polymerization was explored. The synthesized polymer had good biodegradability, which highlighted the advantages of cellulose modification techniques.The results showed that there was only one single spectrum peak in the retention time, which indicated that obtained cellulose-g-PLLA had a higher purity after the homopolymer was removed. According to the D value (Mw/Mn) of GPC, the D value of cellulose-g-PLLA mainly in1.75,1.66,1.56,1.35and1.28, which indicated that narrow molecular weight distributions. The obtained cellulose-g-PLLA had a higher performance than before (DPmax=2.78, DSmax=5.23, MSmax=14.54). The reaction time became shorter and the grafting became more efficient. The optimum synthesis condition was:cellulose/ionic liquid/LA/DMAP equal1:20:8.91:3.39, the reaction time9h, the reaction temperature80℃. Differential scanning calorimetry and thermogravimetric analysis showed that graft parameters directly affect the thermodynamic properties of the polymer. The glass transition temperature and the thermal decomposition temperature reached64.7℃and240℃, respectively, as the grafts improved. The cellulose-g-PLLA had a higher thermodynamic stability.It is a mild and green reaction. In this paper, the selective and final research will provide an efficient, active-controlled new catalyst. It provides the theoretical basis for follow-up application. It also provides a practical reference for cellulose modified material changed to bio-materials via detect of its biodegradability.