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Synthesis, characterization, and properties of ε-caprolactone and carbonate copolymers



A series of copolymers were synthesized by the ring-opening bulk polymerization of ε-caprolactone (CL) and 2-phenyl-5,5-bis(hydroxymethyl) trimethylene carbonate (PTC) with tin(II) 2-ethylhexanoate as a catalyst. These copolymers were further reduced with a palladium/carbonate catalyst to obtain partly deprotected copolymers. The two types of copolymers that were obtained were characterized with 1H-NMR, Fourier transform infrared spectroscopy, UV, gel permeation chromatography, differential scanning calorimetry, and automatic contact-angle measurements. The influences of the monomer feed molar ratio, catalyst concentration, and reaction time as well as the reaction temperature on the copolymerization process were also studied. The copolymerization of CL and PTC monomers was a nonideal copolymerization, and the copolymerization reactivity ratio of CL was higher than that of PTC in the polymerization process. In vitro degradation tests indicated that the partly deprotected copolymers possessed faster degradation rates and greater hydrophilicity than the unreduced copolymers. In vitro release profiles of fluorouracil from the copolymers showed that these two types of copolymers had steady drug-release rates and good controlled-release properties. Moreover, the partly deprotected copolymers had faster drug-release rates than the unreduced copolymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009