| By imitating the LC structure of biologic membranes, the cholesteryl liquid crystal (LC)compound was grafted onto PU surface attempting to improve the blood compatibility of thematerial. The carbon chain with double bonds was introduced onto the end of the cholesterylliquid crystal (LC) compound, subsequently, LC compound was immobilized onto the surface ofPU by the peroxidation grafting of group double bonds on LC compound with PU membrane,expecting the LC molecule become flexible and ordered arranging on surface of PU-LC graftingmembrane, assuming the perennial stable LC domain was formed onto the surface of PU toquench the shedding of LC while applied in practice. The blood compatibility of biologicalmaterial was greatly improved by imitating the LC structure of biologic membranes to the greatextent.The structure and properties of the two LC composites and the synthesized PU-LC graftingmembrane had been characterized through the test of POM, IR, SEM, DSC. Blood compatibilityof those LC/PU composites and PU-LC grafting membranes were assessed by test of thehaemolysis ratio, the dynamic blood clotting and the platelet adhesion. The results turned out thatthe two LC composites, which behaved apparently in thermal-forming LC, was observed withcolorful texture of LC under POM. The test of POM, IR, SEM showed PU-LC graftingmembrane synthesized through peroxidation in which the LC domain was scattered onto thesurface of PU congruously reached to the highest grafting rate with 7% under reactiontemperature 60℃, reaction time 3hr, and LC concentration 25%.Blood compatibility test in vitro showed that the haemolysis ratio of variety of PU-LCmodified membranes were all less than 5% qualified for the biomaterial conduct standard, thedynamic blood clotting test showed that the PU-LC modified membranes by grafting the LC canpostpone the time when the thrombus was formed and decrease the adhesion number of bloodplatelets, improve blood compatibility of PU to the great degree.
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