Poly(trimethylene carbonate) (PTMC) is a biodegradable polymer which doesn't generate any acidic organic compounds after hydrolysis, leading to good biocompatible properties and biomedical application. Poly(TMCM-MOE3OM) and poly(TMCE-MOE4OM), bearing oligo ethylene glycol (OEG) at the side chain of PTMC, were selected to investigate in vitro accelerating hydrolysis behaviors at pH = 7.4 in a phosphate-buffered solution (PBS) through the use of Lipase and NaOHaq. Their degradation behaviors were in contrast to that of PTMC, resulting in the fast degradation in NaOHaq. and the slow degradation by Lipase. The contrast in results of degradations are due to the side chain of hydrophilic OEG which should interact with degradation species.

Poly(trimethylene carbonate) (PTMC) is a well‐known biodegradable polymer with good biocompatible properties which make it suitable for biomedical applications. Poly(5‐[2‐{2‐(2‐methoxyethoxy)ethyoxy}‐ethoxymethyl]‐5‐methyl‐1,3‐dioxa‐2‐one) (PTMC‐MOE3OM) and copolymers, bearing oligo ethylene glycol (OEG) at the side chain of PTMC backbone, were selected to investigate the cloud point behavior by solvents such as PBS, water, 10% ethanol solution and various ionic strengths. A pH‐responsive copolymer, poly(TMCM‐MOE3OM‐co‐(5‐methyl‐5‐carboxylic‐1,3‐dioxane‐2‐one)) as carboxylic acid carbonate showed a decreased critical temperature at pH 2. Photo‐responsive copolymer, poly(TMCM‐MOE3OM‐co‐coumarin derivatives) bearing 1% and 10% of photo‐induced molecules (7‐[(5‐(5‐methyl‐1,3‐dioxa‐2‐one)methoxy)]‐methoxy coumarin (TMCM‐coumarin)) exhibited a low cloud point because of the hydrophobic moieties. Meanwhile, alternative coumarin polymer including 2% of 4‐methyl‐7‐[(5‐(5‐methyl‐1,3‐dioxa‐2‐one)methoxy)butoxy)]‐methoxy coumarin (TMCM‐4‐methyl‐coumarin) has been successfully synthesized and copolymerized as a novel molecule. The various combinations of monomers were studied and the significant properties were determined via external triggers after copolymerization. This study showed basically synthetic progress toward designs and trivial rationalization of thermoresponsive copolymers close to body temperature. At present, various pendant groups as side part affect to the lower critical solution temperature (LCST) and biodegradable polymer in order to utilize the actual external stimuli application. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3466–3474

Poly(trimethylene carbonate) (PTMC) derivatives have been extensively researched for use as low‐toxicity biomaterials. Better biocompatibility and lower toxicity have been achieved by eliminating acid generation from the ester group at the side chains. In this study, thermosensitive PTMC derivatives bearing oligo(ethylene glycol) units are synthesized by ring‐opening polymerization for the development of low‐toxicity and thermosensitive soft materials. The viscoelastic properties of the obtained polymers are then investigated by rheometry to clarify the thermosensitive and molecular weight effects. Furthermore, thermosensitive behaviors and dynamics of these polymers are observed by UV–vis transmittance, DSC, and 1H NMR spectra analysis. These data suggest a mechanism for the thermosensitive behavior where it is surmised that some kind of dehydration phenomenon induces aggregation behavior in aqueous media above lower critical solution temperature. These thermosensitive behaviors provide an important road map for the development of thermosensitive soft materials using ester‐free PTMC derivatives by controlling the thermosensitive behaviors and bulk properties.

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To prepare a thin film, the block copolymer poly(TMCM‐MOE3OM)‐b‐PTMC was prepared with different segment ratios of hydrophilic moiety. The glass transition temperature of poly(TMCM‐MOE3OM)‐b‐PTMC decreased as the content of TMCM‐MOE3OM increased as expected, and it was confirmed that the graft oligo(ethylene glycol) (OEG) affected intermolecular interaction. The polymers grafted with OEG showed a thermoresponsive property, which can be expected to be applied to materials triggered by temperature. A thin film was prepared by mixing block copolymer and cilostazol as a drug, and the distribution of cilostazol was observed. It was confirmed that cilostazol was uniformly distributed on the thin film and that local sustained release could be avoided at the time of elution. The eluting behavior of the thin film from the substrate was apparently affected on the segment ratio of the block copolymer. When the thin film was immersed in PBS, the eluting rate increased as the segment ratio of TMCM‐MOE3OM in the block copolymer increased. As a result, it is possible to control the eluting rate by changing the ratio of the hydrophilicity and the hydrophobicity of the block copolymer, contributing to the creation of a new coating material containing cilostazol.