Synthesis And Characterization Of Heparinized Liquid Crystal Polyacrylate

In this paper, a new type of polymer used as artificial blood vessel was developed. T-style side chain liquid crystalline polymer with polyacrylamide as flexible main chains and heparin as side chains has been designed and synthesized by the condensation reaction between -COOH and -NH2 active groups. The technologcial condition was optimized and obtained by the orthogonal experiment with the addition of heparin, pH, temperature, the rate of agitation and time as factors which effected the performance of liquid crystalline polymer in the preparation process. The optimized technological condition was that: PAM: heparin = 80: 1; pH = 8; time = 1 h; temperature was 45℃; the rate of agitation was 1100 rpm. It was characterized by cholesteric liquid crystal through polarized optical microphotograph. At the mean time, temperature range of liquid crystal phase has been figure out through DTA to be between room temperature 25℃to 121℃; when polyacrylamide: heparin = 200: 1, the liquid crystal phase can not be formed. It was proved that heparin was covalently linked to polyacrylamide chains by IR.The combined material with the similar structure as the structure of the endothelium in the blood vessel was prepared by cross-linkage blending between polyetherurethane and the chain liquid crystalline polymer using bio-inspired under the electric field. The optimized technologcial condition was obtained from the results of the orthogonal experiment: the quantity of chain liquid crystalline polymer was 30%; pH = 4; time = 2.5 h; temperature was 0℃; the electric field intensity was 1.1×105V/m. It was proved by IR that heparin- liquid-crystalline macromolecule was linked to functional polyetherurethane in chemical bond manner. It was found that the performance of anticoagulant of the combined material was all right, but the capability to prepare film was weak, so the combined material can not be used in application.Furthermore, the structure and the performance of anticoagulant of the heparin- liquid-crystalline macromolecule polyetherurethane composite biomaterial was compared under no-electric field. The results have shown that LCP particulate can dispersed with uniformity in the base material under the electric field. At the same time, the microphase separating structure was kept well and the performance of anticoagulant and mechanical characters was improved when the content of the liquid crystalline in composite biomaterial was 20% under the electric field. The results was also shown that the activity of heparin was kept well in the heparin-liquid-crystalline macromolecule. The performance of anticoagulant and enhanced mechanical characters was excellent under the electric field. The technological condition of preparation was simple and in moderation. It was convenient for the industry production and the foreground of industrialization was thrilling.