Enzyme-catalyzed polymerization and degradation of copolymers prepared from ?-caprolactone and poly(ethylene glycol) |
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Authors: | Feng He Suming LiMichel Vert Renxi Zhuo |
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Affiliation: | a Research Center on Artificial Biopolymers, Faculty of Pharmacy, 15 Avenue Charles Flahault, Montpellier 34060, France b Laboratory of Biomedical Polymer Materials Research, Department of Polymer Chemistry, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China |
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Abstract: | Copolymerizations of ?-caprolactone (CL) with monohydroxyl or dihydroxyl poly(ethylene glycol) (PEG) were successfully performed using Novozyme-435 (immobilized lipase B from Candida antartica) as catalyst. Diblock and triblock copolymers with different compositions were characterized by 1H NMR, GPC, DSC and X-ray diffraction. The enzymatic copolymerization carried out in toluene presented higher reaction rate and yield than that in bulk. Increasing the [CL]/[EO] feed ratio resulted in increases of molecular weight (Mn) of copolymers. Moreover, the compositions of triblock copolymers were closer to the monomer feed ratios than those of diblock copolymers. The resulting copolymers were all semicrystalline, the crystalline structure being of the PCL type. Solution cast films were allowed to degrade in a pH 7.0 phosphate buffer solution containing Pseudomonas lipase. Weight loss data showed that the introduction of PEG segments to the PCL main chain did not alter the enzymatic degradation of PCL significantly. |
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Keywords: | Enzymatic copolymerization Enzymatic degradation PCL/PEG copolymer |
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