Preparation And Blood Compatibility Of Polyurethane Modified With Natural Polymer Liquid Crystal

Nowadays, the research on the blood compatibility of biomaterials is very hot, but the biomaterials apply to clinic are still restricted by the thrombosis formed on the surface of biomaterials. Polyurethane (PU) is a popular blood compatibility material, but there are still problems, this paper based on the model of natural biomembrane, prepared composite membranes is blended with natural polymer liquid crystal and polyurethane, and studied their blood compatibility.At first, synthesized propionic ester of hydroxypropyl cellulose (PPC) which is a polymer liquid crystal at body temperature, Their structures and properties were characterized by FTIR, optical polarization microscope, DSC, et al., the results show that PPC is a thermo tropic liquid crystal and displays a cholesteric banded texture. And the conditions of reaction have a strong effect on the thermo property of PPC, the increase of temperature and quantity of propionyl chloride lead to the LC temperature range of PPC get wider and wider, and the melt point decreases too. But also while the degree of substitution of propionic reached 2.35, the LC temperature range is between 34.9℃ and 155.6℃, this make sure PPC display the LC property at body temperature.Then, blended the PPC and PU by solution casting and melting technology, according to the observation results from SEM and AFM, the PPC/PU composite membranes tend to phase separate when they shaped by the solution casting technology, and their hydrophilicity is also better than the others.At last, the blood compatibility was showed by dynamic blood-clotting, hemolysis and protein adsorption. Obviously, the PPC have a positive significance for PU on blood compatibility. Contrast to the COC/PU and COC+PPC/PU composite membrane, COC+PPC/PU composite membrane shows the best blood compatibility than the others.