Study On PET Surface Modification By Plasma And The Blood Compatibility

Because of its good biochemistry stability and the outstanding materials mechanics performance, polyethylene terephthalate (PET) obtains wide spread application, but its surface bio-compatibility limited it was used in more field, such as biomaterial. Surface grafting modification is a important way to enhance the bio-compatibility of polymer. It can effectively unify the blood compatibility and material main body nature. This article uses the plasma surface modified method to treat PET films to introduce the active groups that can improve their blood compatibility. It includes the following contents mainly:1. SO₂ plasma, NH3 plasma are used separately to modify PET surface. Influences of power, treatment time, surface chemistry structure and element content on PET surfacial modification and blood compatibility. The best response conditions are determined. In SO₂ plasma processing, when power is 50W and reaction time is 3rain, the blood compatibility of the modified PET film is best, APTT achieves 57.5s; in NH₃ plasma processing, when power is 70W and reaction time is 3min, the blood compatibility of the modified PET film is best, APTT achieves 42.0s. The blood compatibility of the PET film treated with SO₂ plasma is better than that treated with NH₃ plasma.2. The mixed gas of NH₃ and SO₂ is used to modify PET surface. Influences of two kinds of gas proportion, power, reaction time, the superficial element content on the material surfacial modification and the blood compatible are studied. When the value of SO₂/NH₃ is 10/6, the content of -SO₃H is 49.93% of the surficial introduced polar groups, the modified PET film gains the best blood compatibility, APTT achieves 62.0s.3. NH₃ plasma is used to modify PET films, glutaric dialdehyde is used as crosslinking agent to graft glutanic acid, then the grafting PET films are treated with Ar plasma. The modified PET films obtain surfacial structure that is similar to hydrogel which can improve their blood compatibility. The influence of power on the modified films superficial performance and the blood compatibility is studied. Pure NH3 plasma processing is compared on the similar response condition: NH₃ plasma modified films obtain longer APTT; the water contact angles of the plasma grafting films are stable and that of the NH3 plasma modified films increase quickly during first few days then become constant.The modified films surfacial chemical constitution and the elemental composition are analyzed by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photon spectroscopy (XPS), and indicate that -CO-NH, -COOH, -SO3H and other polar groups are introduced successfully to the modified film surface. The static state contact angle, the surface free energy, in vitro blood compatibility and aging effect are used to value the surface performance and the blood compatibility of the modified PET films. The results indicate that, after above modified methods, superficial static state contact angle of modified PET films obviously reduces, surface free energy remarkable increases.Research of vitro blood compatibility indicate that APTT of the modified PET film is lengthened, -CO-NH, -SO₃H, -COOH markedly influence on intrinsic coagulant system; changes of PT, TT are not obvious, it indicates that the modified surface of PET films can not influence markedly on extrinsic coagulant system.