Synthesis and properties of polycarbonate copolymers of trimethylene carbonate and 2‐phenyl‐5,5‐bis(hydroxymethyl) trimethylene carbonate

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AbstractThe polycarbonate copolymers poly[trimethylene carbonate‐co‐2‐phenyl‐5,5‐bis(hydroxymethyl) trimethylene carbonate] [P(TMC‐co‐PTC)] were synthesized by the ring‐opening polymerization of trimethylene carbonate (TMC) and 2‐phenyl‐5,5‐bis(hydroxymethyl) trimethylene carbonate (PTC) with tin(II) 2‐ethylhexanoate and aluminum isopropoxide as the catalysts. These copolymers were further reduced by a palladium/carbonate (Pd/C; 10%) catalyst to produce partly deprotected copolymers. These two types of copolymers were characterized by 1H‐NMR, Fourier transform infrared spectroscopy, UV spectroscopy, gel permeation chromatography, differential scanning calorimetry, and an automatic contact angle meter. The influences of the feed molar ratio of the monomers, the catalyst concentration, the reaction time, and the reaction temperature on the copolymerization process were also studied. The copolymerization of the TMC and PTC monomers was a nonideal copolymerization, and the copolymerization reactivity ratio of TMC was higher than that of PTC. In vitro degradation tests indicated that the partly deprotected copolymers possessed faster degradation rates and more hydrophilicity than the corresponding unreduced copolymers. Moreover, the degradation of these two type copolymers increased when the pH value of the buffer solutions decreased. In vitro drug‐release experiments 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 corresponding unreduced copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012