A superabsorbent resin was prepared through free-radical polymerization in aqueous solution,which used konjac glucomannan(KGM),acrylic acid(AA)and acrylamide(AM)as raw materials.Graft polymerization was initiated by p...A superabsorbent resin was prepared through free-radical polymerization in aqueous solution,which used konjac glucomannan(KGM),acrylic acid(AA)and acrylamide(AM)as raw materials.Graft polymerization was initiated by potassium persulfate(K2S2O8),with N,N′-methylene-bis-acrylamide(NMBA)was used as crosslinking agent .The relationships between the water absorption of the resin and the amounts of initiator,crosslinker,AA and AM as well as reaction temperature,reaction time were studied.This superabsorbent polymer was capable of absorbing distilled water up to 720 times and 0.9%NaCl solution 110 times in its saturated state at ambient temperature when the mass ratio of KGM to monomer was 1∶4,the amount of initiator was 0.35%(based on the weight of monomer),the neutralization degree of monomer was 80 %,the reaction temperature was 55~65℃,and the amount of crosslinker was 0.075%(based on the weight of monomer).Experimental results indicated that the introduction of nonionic group would be suitable for improving absorption ability and salt-resistance of the resulting hydrogels.展开更多
Green nanophosphors(Gd,Y)PO4:Tb were prepared by solid state chemical reaction of precursors at room temperature.The formation process,particle-size,shape and fluorescence properties of the phosphor were characterized...Green nanophosphors(Gd,Y)PO4:Tb were prepared by solid state chemical reaction of precursors at room temperature.The formation process,particle-size,shape and fluorescence properties of the phosphor were characterized by means of XRD,TEM and solid fluorescence techniques.The results indicate the nanophosphor of(Gd,Y)PO4:Tb belong to the monoclinic system,its space group is P21/ n,its average particle size is 35nm,has better particle dispersion.The phosphor exhibits green fluorescence when excited by ultraviolet radiation of 380nm wavelength.The strongest peak is at 545nm,which assigned to 5D4→7F5 transition of Tb3+ ion.The phosphor is a kind of efficient green-emitting luminescence material.展开更多
文摘A superabsorbent resin was prepared through free-radical polymerization in aqueous solution,which used konjac glucomannan(KGM),acrylic acid(AA)and acrylamide(AM)as raw materials.Graft polymerization was initiated by potassium persulfate(K2S2O8),with N,N′-methylene-bis-acrylamide(NMBA)was used as crosslinking agent .The relationships between the water absorption of the resin and the amounts of initiator,crosslinker,AA and AM as well as reaction temperature,reaction time were studied.This superabsorbent polymer was capable of absorbing distilled water up to 720 times and 0.9%NaCl solution 110 times in its saturated state at ambient temperature when the mass ratio of KGM to monomer was 1∶4,the amount of initiator was 0.35%(based on the weight of monomer),the neutralization degree of monomer was 80 %,the reaction temperature was 55~65℃,and the amount of crosslinker was 0.075%(based on the weight of monomer).Experimental results indicated that the introduction of nonionic group would be suitable for improving absorption ability and salt-resistance of the resulting hydrogels.
文摘Green nanophosphors(Gd,Y)PO4:Tb were prepared by solid state chemical reaction of precursors at room temperature.The formation process,particle-size,shape and fluorescence properties of the phosphor were characterized by means of XRD,TEM and solid fluorescence techniques.The results indicate the nanophosphor of(Gd,Y)PO4:Tb belong to the monoclinic system,its space group is P21/ n,its average particle size is 35nm,has better particle dispersion.The phosphor exhibits green fluorescence when excited by ultraviolet radiation of 380nm wavelength.The strongest peak is at 545nm,which assigned to 5D4→7F5 transition of Tb3+ ion.The phosphor is a kind of efficient green-emitting luminescence material.