Synthesis and thermal properties of novel multiblock biodegradable copolymers derived from polyethylene glycol, ε-caprolactone and p-dioxanone

Multiblock copolymers from polyethylene glycol (PEG), epsilon-caprolactone (CL), and p-dioxanone (PDO) were synthesized and characterized. Triblock copolymers were first synthesized from PEG with number-averaged molecular weights (M-n) of 3000, 4000, and 15000 Daltons, and epsilon-caprolactone in the presence of Sn(Oct)(2). H-1-NMR spectra of these copolymers were recorded, Thermal behaviour and thermal stability of these copolymers were evaluated by differential scanning calorimetry (DSC) and TGA thermograms, respectively. These triblock copolymers with two hydroxyl functional groups were subjected to further block copolymerization with PDO in the presence of Sn(Oct)(2) as catalyst. Thermal behaviours of these copolymers were evaluated by DSC and TGA thermograms. For comparison of block and random copolymer thermal behaviour, random triblock copolymer from PEG, CL, and PDO was prepared and its thermal behaviour was characterized by DSC and TGA.