Viscoelastic Evaluation of Poly(Trimethylene Carbonate)s Bearing Oligoethylene Glycol Units Which Show Thermoresponsive Properties at Body Temperature

Abstract

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.

Synthesis of amphiphilic block copolymer using trimethylene carbonate bearing oligo(ethylene glycol) and investigation of thin film including cilostazol

“…It was successfully synthesized in different composition rate with reference to the literature. [ 32 ] The yield was improved from 14% to 51% by changing the ratio of monomer and initiator, probably because of the concentration of the growing chain end. Unfortunately, their polydispersity is still not sharp, indicating the polymerization manner was not controlled very well.…”

“…Elution test was performed by immersing in PBS with the thin films for 6 and 13 days, which were prepared by dip‐coating of two type of block copolymers having different segment ratios (φ PTMC = 0.94 [ 32 ] and φ PTMC = 0.62) on a SS substrate. Table 2 shows the elution amount from each polymer film into PBS.…”

“…The synthesis of poly(TMCM‐MOE3OM)‐ b ‐PTMC was carried out with reference to the literature. [ 32 ] Poly(TMCM‐MOE3OM)‐ b ‐PTMC was synthesized via anionic polymerization. TMCM‐MOE3OM 0.5 g was dissolved in anhydrous CH 2 Cl 2 and made anhydrous solution using MS4A was added to two‐neck round‐bottom flask under N 2 atmosphere.…”

“…The development of a PTMC derivative having a reasonable stability under physiological conditions is expected for stent coating application. For that reason, we synthesized a block copolymer composed of TMC and TMC derivatives with OEG [ 31,32 ] ; however, the eluting behavior was not suitable for the possible drug eluting stent (DES) application, [ 32 ] because the amount of copolymerization units of TMC derivative bearing OEG was too small. When the eluting behavior is well controlled, the effective drug release would be achieved along with the polymer elution.…”

Thermal Property Control by Copolymerization of Trimethylene Carbonate and Its Derivative Bearing Triphenylmethyl Group

“…It is a characteristic of the PTMC backbone not to produce acidic organic compounds after hydrolysis, so we selected an esterfree type to introduce functional groups for TMC derivatives. As functional groups, OEG groups gave the thermoresponsive properties, [36,39] the resultant polymers were viscous liquids, and were difficult to use as solid materials. Therefore, we recently tried to introduce various substitutents to ester-free type PTMC to create sustainable polymer materials.…”