Renewable Biobased Polymeric Materials: Facile Synthesis of Itaconic Anhydride-Based Copolymers with Poly( l -lactic acid) Grafts

This paper reports a new synthesis of biobased polymers by using itaconic anhydride (IAn) and lactic acid (LA) as renewable starting materials. Poly(lactic acid) (PLA)-graft copolymers were synthesized via two approaches. First, the macromonomer approach utilized IAn for Sn-catalyzed synthesis of PLA-containing macromonomers (IAn-PLA Macro). The macromonomer was radically copolymerized with n -butyl methacrylate (BMA), n -butyl acrylate (BA), methyl methacrylate (MMA), and ethyl methacrylate (EMA) to give efficiently graft copolymers (PLA-Graft copolymer ( I )) with molecular weight M n up to 1.61 × 10 5 having biomass content higher than 34 wt %. Second, the copolymer approach employed first IAn as comonomer for radical copolymerization with BMA, giving rise to IAn-BMA copolymer with M n higher than 5.76 × 10 4 . Then, Sn-catalyzed grafting of PLA onto IAn moiety of the copolymer produced PLA-Graft copolymer ( II ) with M n higher than 5.88 × 10 4, showing biomass content ≥29 wt %. In addition, radical homopolymerization of IAn was examined to give polyIAn. By using these two approaches employing IAn as a starting reactive material, PLA-graft copolymers were obtained as “biomass-plastics”. Properties of PLA-Graft copolymers ( I ) were also examined, which revealed possible applications for coatings and plastics. Furthermore, the IAn-containing graft copolymers will be a convenient starting biomass polymer having reactive IAn moiety in the main chain for further grafting or various functional group-introducing reactions.