“One pot” homogeneous synthesis of thermoplastic cellulose acetate-graft-poly(l-lactide) copolymers from unmodified cellulose

Using native cellulose as the starting material, cellulose acetate- graft -ploy ( l -lactide) (CA- g -PLA) copolymers were successfully synthesized by “one-pot” process in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). In this process, cellulose was first reacted with acetic anhydride, yielding cellulose acetate (CA), and then ring opening graft copolymerization of l -lactide was carried out from the residual hydroxyl groups of CA in the same solution using 4-dimethylaminopridine (DMAP) as the catalyst. Both acetyl and ploy ( l -lactide) contents in CA- g -PLA copolymers could be well controlled by changing reaction conditions. The structures and thermal properties of CA- g -PLA copolymers were characterized. The glass transition temperature T g of copolymers decreased with increasing PLA content. Compared to the pure PLA and cellulose- graft -PLA copolymers, the CA- g -PLA copolymers possessed better thermo mechanical properties in a temperature range of 60–130 °C. When the molar substitution of PLA (MS PLA ) was above 1.71, the CA- g -PLA copolymers exhibited thermoplastic behavior and could be processed by conventional thermal processing methods, such as injection molding and melt spinning.