Biodegradable poly(ethyleneglycol)-poly(valerolactone)-poly(ethyleneglycol) [PEG-PVL-PEG] copolymers were synthesized through ring opening polymerization of δ-valerolactone (VL) followed by the coupling of monomethoxy poly(ethyleneglycol-poly(valerolactone) (mPEG-PVL) with hexamethylene diisocyanate (HDI). The copolymers were characterized by ¹H NMR, FT-IR, and GPC. Block copolymers of PEG and PVL with different VL/PEG molar ratios were successfully synthesized. One...