Grafting copolymerization of styrene and acrylic acid onto polypropylene fabric had been studied by using a pre-irradiation technique. The polypropylene fabric Samples were irradiated by Y-ray and electron beam under ...Grafting copolymerization of styrene and acrylic acid onto polypropylene fabric had been studied by using a pre-irradiation technique. The polypropylene fabric Samples were irradiated by Y-ray and electron beam under the conditions of air and nitrogen gas, respectively. The effect of absorbed dose, monomer concentration in solvent, reaction temperature and reaction time on the degree of grafting were determined. The effects of metallic salts and sulphuric acid on the grafting yield of acrylic acid were also examined. The samples irradiated by electron beam give a much higher degree of grafting than those by Y -ray when styrene was grafted to polypropylene fabric. However, the grafting yield of acrylic acid on polypropylene fabric in the presence of metallic salts and sultric acid showed the opposite results from the case of styrene. This effect is reasonably interpreted by assuming that the grafting is dominated by trapped radicals and peroxides in pre-irradiated polypropylene.展开更多
Radiation induced graft polymerization on polymeric matrix followed by functionalization is widely accepted for the preparation of metal adsorbents. In this paper, a pre-irradiation method was used for emulsion graft ...Radiation induced graft polymerization on polymeric matrix followed by functionalization is widely accepted for the preparation of metal adsorbents. In this paper, a pre-irradiation method was used for emulsion graft polymerization of 4-hydroxybutyl acrylate glycidylether (4-HB) onto polyethylene/polypropylene (PE/PP) nonwoven fabric. The degree of grafting (Dg) which can be calculated by weight increment was determined as a function of reaction time, irradiation dose, and monomer concentration. After 30 kGy irradiation, with 4-HB concentration of 5%, surfactant Span 20 of 0.5% at 40°C for 2 h, the trunk polymer was made grafted at a Dg of 135%. 4-HB-grafted PE/PP nonwoven fabric was modified by ethylenediamine (EDA) in isopropyl alcohol (IPA) as a solvent at 60°C. With a Dg of 135%, the amine group density of the adsorbent is 2.8 mmol/g. The adsorption test was carried out by batch experiment in several metal ion solutions, and the removal ratio from the EDA modified adsorbent of the metal ions is in the order of Cu2+ > Pb2+ > Zn2+ > Ni2+ > Li+. Compared with glycidyl methacrylate (GMA) which is a typical functional monomer for graft polymerization, 4-HB-grafted adsorbent exhibited not only better mechanical property but also higher adsorption capacity of Cu2+ and Pb2+.展开更多
Temperature is a crucial factor that is intrinsically related to fuel cell performances and categorizes the proton exchange membranes(PEM)into high and low temperature(HT,LT)types.With water as proton conductor,workin...Temperature is a crucial factor that is intrinsically related to fuel cell performances and categorizes the proton exchange membranes(PEM)into high and low temperature(HT,LT)types.With water as proton conductor,working temperature of LT-PEM is limited below 100℃.PEM fuel cell with an elevated temperature(HT-PEMFC,>120℃)thus attracts much research attention on account of the significant benefits,such as simpler water management,faster electrode kinetics,improved CO tolerance of platinum catalyst,and heat recovery.As a well-known concept,numerous polymer membranes with doping phosphoric acid(PA)have been investigated for HT-PEMFC.In this review,the development trend for the most advanced technology of HT-PEM polybenzimidazole(PBI)membrane,other hydrocarbon-based membrane,and fluorinated membrane produced via pre-irradiation induced grafting with respect to their synthesis,properties,critical issues,and corresponding solutions is presented.展开更多
基金the National Natural Science Foundation of China (29404031 ) and the Korea Science and Technology Foundation
文摘Grafting copolymerization of styrene and acrylic acid onto polypropylene fabric had been studied by using a pre-irradiation technique. The polypropylene fabric Samples were irradiated by Y-ray and electron beam under the conditions of air and nitrogen gas, respectively. The effect of absorbed dose, monomer concentration in solvent, reaction temperature and reaction time on the degree of grafting were determined. The effects of metallic salts and sulphuric acid on the grafting yield of acrylic acid were also examined. The samples irradiated by electron beam give a much higher degree of grafting than those by Y -ray when styrene was grafted to polypropylene fabric. However, the grafting yield of acrylic acid on polypropylene fabric in the presence of metallic salts and sultric acid showed the opposite results from the case of styrene. This effect is reasonably interpreted by assuming that the grafting is dominated by trapped radicals and peroxides in pre-irradiated polypropylene.
文摘Radiation induced graft polymerization on polymeric matrix followed by functionalization is widely accepted for the preparation of metal adsorbents. In this paper, a pre-irradiation method was used for emulsion graft polymerization of 4-hydroxybutyl acrylate glycidylether (4-HB) onto polyethylene/polypropylene (PE/PP) nonwoven fabric. The degree of grafting (Dg) which can be calculated by weight increment was determined as a function of reaction time, irradiation dose, and monomer concentration. After 30 kGy irradiation, with 4-HB concentration of 5%, surfactant Span 20 of 0.5% at 40°C for 2 h, the trunk polymer was made grafted at a Dg of 135%. 4-HB-grafted PE/PP nonwoven fabric was modified by ethylenediamine (EDA) in isopropyl alcohol (IPA) as a solvent at 60°C. With a Dg of 135%, the amine group density of the adsorbent is 2.8 mmol/g. The adsorption test was carried out by batch experiment in several metal ion solutions, and the removal ratio from the EDA modified adsorbent of the metal ions is in the order of Cu2+ > Pb2+ > Zn2+ > Ni2+ > Li+. Compared with glycidyl methacrylate (GMA) which is a typical functional monomer for graft polymerization, 4-HB-grafted adsorbent exhibited not only better mechanical property but also higher adsorption capacity of Cu2+ and Pb2+.
文摘Temperature is a crucial factor that is intrinsically related to fuel cell performances and categorizes the proton exchange membranes(PEM)into high and low temperature(HT,LT)types.With water as proton conductor,working temperature of LT-PEM is limited below 100℃.PEM fuel cell with an elevated temperature(HT-PEMFC,>120℃)thus attracts much research attention on account of the significant benefits,such as simpler water management,faster electrode kinetics,improved CO tolerance of platinum catalyst,and heat recovery.As a well-known concept,numerous polymer membranes with doping phosphoric acid(PA)have been investigated for HT-PEMFC.In this review,the development trend for the most advanced technology of HT-PEM polybenzimidazole(PBI)membrane,other hydrocarbon-based membrane,and fluorinated membrane produced via pre-irradiation induced grafting with respect to their synthesis,properties,critical issues,and corresponding solutions is presented.
