Synthesis And Properties Of Surface Phospholipid-Modified Silicon-PU

In order to obtain a biomedical material with good physical inertia and biocompatibility, A polydimethylsiloxane (PDMS) modified polyurethane elastomer was first synthesized and then the surface of this PDMS modified polyurethane was modified by phospholipid which can effectively reduce protein and platelet adsorption to improve the surface properties of anticoagulant.Firstly, A series of polyurethane elastomer with varying proportion of (PDMS) were synthesized based on isophorone diisocyanate(IPDI),isophorone diamine(IPDA) as the hard segments and polytetrahydrofuran glycol(PTMG), polydimethylsiloxane(PDMS) as the soft segments. The polymers morphology and microphase separation of the series of polyurethane were investigated by fourier transfer infrared spectroscopy(FTIR), X-ray diffraction(WAXD) and differential scaning calorimetry(DSC). The results show that phase separation increase with increasing of PDMS. The molecular weight, mechanical and surface property of the polyurethane with different PDMS content were studied by gel permeation chromatography(GPC),tensile test and contact angle test. The results show that the molecular weight and tensile strength decrease with increasing of PDMS, the surface contact angle increase with increasing of PDMS. When the content of PDMS increase from 0% to 25%, the tensile strength decrease from 7.57MPa to 0.65MPa, the molecular weight decreased from 40,000 to 26,000,and surface contact angle increase from 72°to above 95°.Secondly, A hydroxyl MPC(MPCOH) monomer were synthesized from many materials such as: glycol, phosphorus trichloride, 2-hydroxyethyl methacrylate, 2-methylaminoethanol. Infrared and nuclear magnetic resonance test were used to characterize the chemical structure of MPCOH, the results showed consistence with the chemical structure. Besides that, a hydroxyl PEO-MPC monomer was also synthesized in order to modify the PDMS-modified PU surface.Lastly, two kind of PDMS-modified polyurethane film surfaces were modified by PEO and PEO-MPC. Through the surface contact test, it showed that the water contact angle dropped from 95°to 70°when PU film surface graftedPEO, while the water contact angle dropped from 95°to 42°when PU film surface grafted PEO-MPC. Platelet adhesion test showed that two modification had increased the surface property of anti-clotting, and that the surface grafted PEO-MPC showed better anticoagulant performance.