The Synthesis And Surface Modification Of Polyurethane Biomaterials

Polycarbonate diol was synthesized using diphenyl carbonate and 1,6-hexanediol. It was then used to prepared polycarbonate urethane(PCNU) with 4,4ËŠ-methylene diphenyl diisocyanate and 1,4-butanediol by melting one-shot method and solution two-shot method in order to study its structure and improve its blood compatibility. Effects of polymerization conditions on the properties of the polymer were studied, including the reaction temperature, time and concentration of the system, and the optimum conditions were reached. The polymer was characterized by IR,GPC,DSC,TG,SAXS and tensile experiments, results showed there were two glass transitions and it was the partial micro-phase segregation structure, However, the phase segregation degree was affected by the soft segment relative molecular mass, composition and polymeric methods. Those results agreed with that from SAXS. TG results showed there were two obvious stages on its thermodecomposition, which was the same with other polyurethanes. The effects of composition and the soft segment relative molecular mass on mechanical properties were studied. The results showed all polymers met with the requirement of polyurethane as biomaterials in vivo. When the soft segment relative molecular mass was 2000, the polymers had larger tensile strength and elongation, and the solution two-shot method was better than melting one-shot method. The micro-crosslinked PDMS-PCNU was prepared by improved melting one-shot method. Effects of polymerization conditions such as the reaction temperature, time and concentration of the system on the properties of the polymer were studied, and the optimum conditions were reached. The products were characterized by IR,DSC,TG and SAXS. Results suggested that there were two glass transitions but unobvious, and the phase segregation degree was reduced by crossing of multi-functional organic siloxane polymer. Results agreed with that from SAXS. From TG diagram there were still two stages when a litter multi-functional organic siloxane polymer jointed. As the quantity increased, the boundary became unobvious and the highest decomposition temperature was reached. The two new compounds of dimethyl amido hydroxy polyethylene glycol and the hydroxyl polyethylene glycol with sulfoammonium amphoteric ion were devised and synthesized by two paths using polyethylene glycol. The each step products were characterized by IR and 1H-NMR, Results agreed with devised structure, and the synthetic conditions and the effect factors were analyzed. The compounds were grafted in the surface of PCNU by functional reactions. The superficial elements were analyzed by electron spectroscopy for chemical (ESCA), and the ESCA of C1s and N1s were fitted by Gaussion function. Results suggested that the object product were successfully synthesized. These polymers would be beneficial to improve the blood compatibility.