Synthesis And Characterizafion Of Poly(ε-caprolactone)and Block Copolymers Of ε-caprolactone With Glycol

At present, poly(s-caprolactone)(PCL) is a hot research as a biodegradable. It is nontoxic and has excellent biocompatibility、blood compatibility and drug penetrability. It presents broad application prospects in the field of biochemical such as sutures, sustained drug-delivery devices and scaffolds in tissue engineering. Crystallization of polymer materials is an important research direction in the polymer field. This thesis is centered on PCL and its copolymers, which are the main two research subjects, and deeply studies its crystalline morphology of block copolymer.Firstly, we get PCL homopolymer by polymerizing the s-caprolactone monomer open-loop using Sn(Oct)2as the initiator. Then we can obtain different molecular weight of PCL homoploymer by changing the dosage of Sn(Oct)2, the polymerization temperature and polymerization time. Using PCL as the research object, we get crystallization temperature (Tc) and melting temperature (Tm) of PCL homopolymer by using DSC analysis; and get PCL’s crystal type by XRD test. Lastly, using the polarizing microscope to study the crystallization temperature, crystallization time and the molecular weight of PCL and other factors on the PCL homopolymer crystal morphology.PCL also has its own drawbacks such as strong crystallization ability, low biodegradable speed and the hydrophobic polymer, it has some limitation only by adjusting molecular weight and distribution to control the degradation speed. Therefore, when polyethylene glycol (PEG) is introduced into the PCL fragment, it is expected to produce new biodegradable materials through copolymerization. In the study, a series of different molecular PCL-PEG-PCL. Triblock copolymers, as well as different molecular weight PEG segments while maintaining the same embedded segment copolymers was synthesized by ring opening polymerization of ε-caprolactone initiated by PEG and Sn(Oct)2under the N2. FTIR、1H-NMR、DSC and POM experiments were used to characterize the structure and crystallization properties of the PCL-PEG-PCL triblock copolymer. The test results show that the reaction of polymerization of the triblock copolymer is controllable reaction, we can control the molecular weight of the polymer by adjusting the proportion of PEG and PCL and the introduction of the polyethylene glycol component can effectively improve the hydrophilic of the PCL-PEG-PCL triblock copolymer and has greater impact on the copolymer crystalline properties.