Preparation And Structural Properties Of Biomedical Polyurethane Materials Containing Polyethylene Glycol Or Ammonium Phosphate Zwitterionic Components

With the interdisciplinary and development of material,medical and biological sciences,biomedical research and development of biomaterials has played an important role in improving the clinical medical levels.Among them polyurethane(PU)has attracted much attention because of its excellent mechanical properties and biocompatibility.To obtain specific and multiple uses as medical implant biomaterial,we perform chemical and/or physical modifications on PU.Surface modification is to graft a specific molecular structure onto the surface of PU.Bulk modification means the main chain of PU is changed.Both modifications help adjusting the hydrophilicity,the blood compatibility and the tissue compatibility of the material.In this thesis,we have prepared the PU material with both the surface and bulk modifications to achieve comparable physical and biological properties.Namely,we have prepared several series of PU,1)PU is surface modified with polyethylene glycol(PEG)of different lengths,or phosphorylcholine(PC)terminated PEG;2)PU is synthesized with PEG or PC as diol segment in the main chain.The Fourier transform infrared spectroscopy(FT-IR),X-ray spectroscopy(EDS)have been used to investigate the structures of the modified materials,such as soft/hard segmental ratios and the micro-phase separation.The main contents are stated as follows:PEG with molecular weight of 200,600 and 2000 g/mol and PC terminated PEG200 were grafted onto the surface of PU.ATR-FTIR and EDS were used to determine the structure and composition of the surface.The blood compatibility was evaluated by such tests as recalcification,hemolysis and platelet adhesion.The results showed that the biocompatibility and anticoagulant properties were improved for the PEG and PEG-PC modified PU.PU was synthesized with PEG2000 as the soft segment.PU with PC on the main chain was synthesized too.FT-IR was used to semi-quantitatively determine the segmental composition,GPC was used to determine the average molecular weight of the two series of PU.The results showed that we did not get the controlled segmental ratios as we expected.