Synthesis Of 4-methyl-ε-caprolactone Based Polyester And Their Applications In Biomaterials

4-methyl-s-caprolactone (MeCL) based polyesters with excellent biodegradability were prepared by ring-opening polymerization. The molecular weight and structures were characterized by NMR and SEC. Microspheres were prepared from polymers and characterized by SEM. Micropattern on polymeric surface was prepared following soft lithography strategy. The physical properties of abovementioned materials were investigated by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and Dynamic thermomechanical analysis (DMA) etc. The biocompatibility and drug release behavior of the prepared materials were also included. The main results are summarized as follows:(1) The 4-methyl-ε-caprolactone was synthesized from 4-methyl cyclohexanone by Baeyer-Villiger reaction. The monomer reactivity ratios for CL (r1) and MeCL (r2) with different catalysts were determined in a kinetic study. Values r1 and r2 of copolymerization catalyzed by Novozym 435 were significantly different. The value of r1 was much higher than that of r2, indicating that higher reactivity of CL compared to MeCL by enzymatic polymerization. However, values r1 and r2 in the copolymerization catalyzed by Sn(Oct)2 were very close to 1. This indicates that the reaction system was a nearly ideal copolymerization and random copolymers of CL and MeCL could obtained using Sn(Oct)2 as catalyst.(2) A series of copolymers containing s-caprolactone (CL) and 4-methyl-ε-caprolactone (MeCL) were synthesized by ring-opening polymerization (ROP) using Tin(Ⅱ) bis(2-ethylhexanoate)(Sn(Oct)2) or Novozym 435 as catalyst. The molecular structure and weight of copolymers were determined by Nuclear Magnetic Resonance (NMR) and Size Exclusion Chromatography (SEC). The results of DSC and XRD consistently indicated that the copolymers were inclined to be amorphous with the increasing of MeCL fraction. Microspheres were prepared from copolymers and characterized by SEM. The average diameter of microspheres was ranging from 350 to 450μm. The preliminary degradability and biocompatibility studies on these materials were also assessed. The result showed that the degradation rate was dramatically increased at the present of MeCL units and copolymers were also noncytotoxic as PCL(3) A series of poly(MeCL) diols were synthesized by ROP and these hydroxyl end-groups were further acrylated. The molecular structure and weight of prepolymers were determined by Nuclear Magnetic Resonance (NMR) and Size Exclusion Chromatography (SEC). The crosslinkable precursors of poly(MeCL) diacrylates mixed with photoinitiator was curd by UV light. The crystallinity, mechanical property and hydrophilicity of cross-linked polymers were determined by XRD, DMA and contact angle meter. The elastic modulus of materials was similar with cartilaginous tissue. Micropattern on polymeric surface was prepared following soft lithography strategy. The drug release profile demonstrated that the release rate was increased with increasing molecular weight of precursors.