Potential transparent PLA impact modifiers based on PMMA copolymers

Two parallel routes were employed to prepare potential transparent impact modifiers for polylactide(PLA). Poly(butadiene-co-methyl methacrylate-co-butyl methacrylate-co-hydroxyethyl methacrylate) or poly(butadiene-co-methyl methacrylate-co-butyl acrylate-co-hydroxyethyl methacrylate) (collectively abbreviated as BMBH copolymer) was prepared by free radical method, possessing polybutadiene domain as rubbery segment to absorb impact energy. It also contained another segment which was composed of methyl methacrylate based polymers to provide optical transparency. Compound of PLA and BMBH copolymers showed an increase of impact strength of only 12% compared to virgin PLA. The other copolymer, poly(butadiene-co-lactide-co-methyl methacrylate-co-butyl methacrylate) (abbreviated as BLMB), consisted of not only polybutadiene and methyl methacrylate based polymer, but also polylactide segment to ascertain compatibility with the PLA matrix. Addition of BLMB copolymers increased the impact strength of PLA up to 25%, while retaining optical transparency.