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Enzymatic Degradation of Block Copolymers Prepared from ε-Caprolactone and Poly(ethylene glycol)

2002; American Chemical Society; Volume: 3; Issue: 3 Linguagem: Inglês

10.1021/bm010168s

1526-4602

Suming Li, Henri Garreau, B. Pauvert, Jonathan G. McGrath, Alexandra Toniolo, Michel Vert,

Advanced Polymer Synthesis and Characterization

Block copolymers were prepared by ring-opening polymerization of epsilon-caprolactone in the presence of monohydroxyl or dihydroxyl poly(ethylene glycol) (PEG), using Zn powder as catalyst. The resulting poly(epsilon-caprolactone) (PCL)-PEG diblock and PCL-PEG-PCL triblock copolymers were characterized by various analytical techniques such as NMR, size-exclusion chromatography, differential scanning calorimetry, and X-ray diffraction. Both copolymers were semicrystalline polymers, the crystalline structure being of the PCL type. Films were prepared by casting dichloromethane solutions of the polymers on a glass plate. Square samples with dimensions of 10 x 10 mm were allowed to degrade in a pH = 7.0 phosphate buffer solution containing Pseudomonas lipase. Data showed that the introduction of PEG blocks did not decrease the degradation rate of poly(epsilon-caprolactone).