Abstract: A polylactide copolymer comprises a graft copolymer of a hydrophobic backbone polymer having a plurality of pendant hydroxyl groups and lactide. In one example, a polylactide includes a graft copolymer of a poly(1,5-cyclooctadiene-co5-norbornene-2-methanol) copolymer and lactide. A method of preparing a toughened polylactide comprises forming a hydrophobic backbone copolymer having a plurality of pendant hydroxyl groups and forming a polylactide graft copolymer by reacting the hydrophobic backbone copolymer having a plurality of pendant hydroxyl groups with lactide, wherein polymerized lactide stems from at least one of the plurality of pendant hydroxyl groups.