A new monomer, phenylmethyl [2-(6-methyl-2,5-dioxo-3-morpholinyl)] ethyl ether (monomer 1), was synthesised and used to prepare copolymers with L-lactide. Different feed ratios of monomer 1 to L-lactide (6 and 20 mol%) were used. The copolymers (PLS2) have ester and amide functional groups in the backbone, as well as pendant free hydroxy functional groups. The presence of free hydroxy groups was further confirmed by reacting with diisocyanate-terminated poly(ethylene glycol) (DIPEG). The copolymers of PLS2 with DIPEG were crosslinked to varying degrees, depending on the amount of free hydroxy groups in PLS2. The addition of poly(ethylene glycol) decreased the T-g or increased the amorphous property of the polylactide drastically.