Modification of poly(tetrafluoroethylene)(PTFE) films with 2-methacryloyloxyethyl phosphorylcholine(MPC) was performed by low-temperature plasma treatment and grafting polymerization.Surface properties of PTFE were ch...Modification of poly(tetrafluoroethylene)(PTFE) films with 2-methacryloyloxyethyl phosphorylcholine(MPC) was performed by low-temperature plasma treatment and grafting polymerization.Surface properties of PTFE were characterized by attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectra,X-ray photoelectron spectroscopy(XPS) ,and static contact angle.The results show that MPC has been grafted onto PTFE film surface successfully.Contact angle for the modified PTFE films in the water decreased from 108°to 58.25°,while surface energy increased from 17.52 mN/m to 45.47 mN/m.The effects of plasma treatment time,monomer concentration and grafting time on degree of grafting were determined.In the meanwhile,blood compatibility of the PTFE films was studied by checking thrombogenic time of blood plasma.展开更多
Graft copolymerization is one of the most attractive methods to modify natural polymers. In this study, graft copolymerization of acylic acid onto chitosan in aqueous media by ceric ammonium nitrate was investigated. ...Graft copolymerization is one of the most attractive methods to modify natural polymers. In this study, graft copolymerization of acylic acid onto chitosan in aqueous media by ceric ammonium nitrate was investigated. The graft copolymerization reaction was carried out in a three necked flask maintained at 70＋/-0.05 ℃ under nitrogen atmosphere in a homogeneous aqueous phase （containing a small potion of acetic acid） by using ceric ammonium nitrate as an initiator. Evidence of grafting was obtained. The synthetic conditions were systematically optimized through studying the influential factors on grafting. The effectiveness of each individual factor was investigated by calculating and monitoring the variations of the grafting parameters [like monomer conversation Cm, grafting efficiency （Ge） and viscosity]. Under optimum conditions monomer conversion of 100.5% and graft efficiency of 94% were obtained, at temperature of 70℃. Flocculating ability of the copolymerization product of chitosan was studied by using Kaolin suspension as the flocculating object. And the application of the product was applied in Huayue dyeing plant. The results indicate that the higher the viscosity is, the better the flocculating ability of the copolymerization product of chitosan will be. The flocculating percentage reaches 96.0%, when the concentration of the product is only 1.0 mg/L and pH fixed at 7.0. Suitable separating mixtures for the grafted copolymer were chosen and the investigation of flocculation ability of the grafted copolymer was carried out with the aim of developing a good flocculant for wastewater treatment. A test of treating dyeing wastewater with the grafted copolymer was carried out and showed that grafting of Acrylic Acid with chitosan has a high COD removal rate 75% to the dyeing wastewater when the concentration is only 6.0 mg/L.展开更多
文摘Modification of poly(tetrafluoroethylene)(PTFE) films with 2-methacryloyloxyethyl phosphorylcholine(MPC) was performed by low-temperature plasma treatment and grafting polymerization.Surface properties of PTFE were characterized by attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectra,X-ray photoelectron spectroscopy(XPS) ,and static contact angle.The results show that MPC has been grafted onto PTFE film surface successfully.Contact angle for the modified PTFE films in the water decreased from 108°to 58.25°,while surface energy increased from 17.52 mN/m to 45.47 mN/m.The effects of plasma treatment time,monomer concentration and grafting time on degree of grafting were determined.In the meanwhile,blood compatibility of the PTFE films was studied by checking thrombogenic time of blood plasma.
文摘Graft copolymerization is one of the most attractive methods to modify natural polymers. In this study, graft copolymerization of acylic acid onto chitosan in aqueous media by ceric ammonium nitrate was investigated. The graft copolymerization reaction was carried out in a three necked flask maintained at 70＋/-0.05 ℃ under nitrogen atmosphere in a homogeneous aqueous phase （containing a small potion of acetic acid） by using ceric ammonium nitrate as an initiator. Evidence of grafting was obtained. The synthetic conditions were systematically optimized through studying the influential factors on grafting. The effectiveness of each individual factor was investigated by calculating and monitoring the variations of the grafting parameters [like monomer conversation Cm, grafting efficiency （Ge） and viscosity]. Under optimum conditions monomer conversion of 100.5% and graft efficiency of 94% were obtained, at temperature of 70℃. Flocculating ability of the copolymerization product of chitosan was studied by using Kaolin suspension as the flocculating object. And the application of the product was applied in Huayue dyeing plant. The results indicate that the higher the viscosity is, the better the flocculating ability of the copolymerization product of chitosan will be. The flocculating percentage reaches 96.0%, when the concentration of the product is only 1.0 mg/L and pH fixed at 7.0. Suitable separating mixtures for the grafted copolymer were chosen and the investigation of flocculation ability of the grafted copolymer was carried out with the aim of developing a good flocculant for wastewater treatment. A test of treating dyeing wastewater with the grafted copolymer was carried out and showed that grafting of Acrylic Acid with chitosan has a high COD removal rate 75% to the dyeing wastewater when the concentration is only 6.0 mg/L.
