Mesoporous silica materials were synthesized via a sol-gel method employing a room temperature ionic liquid （1-butyl-3-methylimidazolium tetrafiuoroborate, [bmim][BF4]） as a new solvent medium and further modified w...Mesoporous silica materials were synthesized via a sol-gel method employing a room temperature ionic liquid （1-butyl-3-methylimidazolium tetrafiuoroborate, [bmim][BF4]） as a new solvent medium and further modified with surfactant （hexadecyl-trimethyl-ammonium bromide, CTAB） as a pore templating material. The synthesized samples were characterized by the transmission electron microscopy, X-ray diffraction, and N2 adsorption-desorption techniques. The results indicated that the mesoporous silica synthesized by using [bmim][BF4] and CTAB as mixed templates showed better mesostructural order and smaller pore size, compared with mesoporous silica materials synthesized by using single [bmim][BF4] as template under the same conditions. This indicates that the presence of surfactant can affect the microstructures of silica prepared by＇the present synthesis method.展开更多
This research was studied to prepare styrene-methyl methacrylate copolymer sheet （S-co-MMA sheet） by using DPNR （deproteinized natural rubber） as an impact modifier. The DPNR was prepared by adding SDS （sodium do...This research was studied to prepare styrene-methyl methacrylate copolymer sheet （S-co-MMA sheet） by using DPNR （deproteinized natural rubber） as an impact modifier. The DPNR was prepared by adding SDS （sodium dodecyl sulfate） into the HANR （high-ammoniated natural rubber latex） and followed by centrifugation. It was found that DPNR was successfully prepared with the lowest nitrogeneous content about 0.034±0.01% w/w by adding SDS for 1.00 phr and centrifugation at 12,000 rpm. Then DPNR was grafted with styrene and methyl methacrylate （DPNR-g-S/MMA） obtained by emulsion polymerization. The effects of DPNR-g-S/MMA were studied by varied the amount of SDS and redox initiator. From this result the grafting efficiency DPNR-g-S/MMA was higher than that of NR-g-S/MMA. The DPNR-g-S/MMA was used as an impact modifier in S-co-MMA sheet. Furthermore, the appropriate quantities of styrene monomer and DPNR-g-S/MMA were also investigated. While DPNR-g-S/MMA was used as impact modifier in S-co-MMA sheet, the result was shown DPNR-g-S/MMA improve impact strength of S-co-MMA sheet. Scanning electron micrographs of S-co-MMA sheet with DPNR-g-S/MMA was found the smooth fracture surface. Thus impact strength of S-co-MMA/gDPNR sheet was high and physical properties of S-co-MMA/gDPNR sheet could be able to be accepted in industry. Concisely, DPNR-g-S/MMA can be used as an impact modifier in S-co-MMA sheet.展开更多
Techniques for fabricating solution-processed zinc oxide(ZnO)-based thin-film transistors(TFTs)are feasible with solution using various routes.Here,ZnO TFTs were fabricated via sol-gel method using zinc acetate as the...Techniques for fabricating solution-processed zinc oxide(ZnO)-based thin-film transistors(TFTs)are feasible with solution using various routes.Here,ZnO TFTs were fabricated via sol-gel method using zinc acetate as the starting reagent with different modifiers and solvents.The ZnO thin-film semiconductors with well-controlled,preferential crystal orientation and densely packed ZnO crystals can be prepared with the optimized fabrication conditions,exhibiting excellent field-effect far exceeding those of hydrogenated amorphous silicon(a-Si:H).However,the field-effect characteristics of ZnO TFTs were different for different precursor systems which were constituted by zinc acetate,modifiers and solvents.The co-modification of acetoin and monoethanolamine for the precursor system exhibited higher extent of crystal orientation and field-effect.The maximum mobility of 7.65 cm2V-1s-1 and current on-to-off ratio of^105–106 have been obtained.展开更多
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.50564006）, the Natural Science Foundation From Science and Technology Committee of Yunnan （No.2005E0042）, and the Specialized Research Foundation for the Doctoral Program of Higher Education of China （No.20070674001）. We also thank Academician Si-shen Xie, Institute of Physics of Chinese Academy Sciences for helping with an SEM facility.
文摘Mesoporous silica materials were synthesized via a sol-gel method employing a room temperature ionic liquid （1-butyl-3-methylimidazolium tetrafiuoroborate, [bmim][BF4]） as a new solvent medium and further modified with surfactant （hexadecyl-trimethyl-ammonium bromide, CTAB） as a pore templating material. The synthesized samples were characterized by the transmission electron microscopy, X-ray diffraction, and N2 adsorption-desorption techniques. The results indicated that the mesoporous silica synthesized by using [bmim][BF4] and CTAB as mixed templates showed better mesostructural order and smaller pore size, compared with mesoporous silica materials synthesized by using single [bmim][BF4] as template under the same conditions. This indicates that the presence of surfactant can affect the microstructures of silica prepared by＇the present synthesis method.
文摘This research was studied to prepare styrene-methyl methacrylate copolymer sheet （S-co-MMA sheet） by using DPNR （deproteinized natural rubber） as an impact modifier. The DPNR was prepared by adding SDS （sodium dodecyl sulfate） into the HANR （high-ammoniated natural rubber latex） and followed by centrifugation. It was found that DPNR was successfully prepared with the lowest nitrogeneous content about 0.034±0.01% w/w by adding SDS for 1.00 phr and centrifugation at 12,000 rpm. Then DPNR was grafted with styrene and methyl methacrylate （DPNR-g-S/MMA） obtained by emulsion polymerization. The effects of DPNR-g-S/MMA were studied by varied the amount of SDS and redox initiator. From this result the grafting efficiency DPNR-g-S/MMA was higher than that of NR-g-S/MMA. The DPNR-g-S/MMA was used as an impact modifier in S-co-MMA sheet. Furthermore, the appropriate quantities of styrene monomer and DPNR-g-S/MMA were also investigated. While DPNR-g-S/MMA was used as impact modifier in S-co-MMA sheet, the result was shown DPNR-g-S/MMA improve impact strength of S-co-MMA sheet. Scanning electron micrographs of S-co-MMA sheet with DPNR-g-S/MMA was found the smooth fracture surface. Thus impact strength of S-co-MMA/gDPNR sheet was high and physical properties of S-co-MMA/gDPNR sheet could be able to be accepted in industry. Concisely, DPNR-g-S/MMA can be used as an impact modifier in S-co-MMA sheet.
基金supported by the Major State Basic Research Development Program of China(Grant No.10332020)
文摘Techniques for fabricating solution-processed zinc oxide(ZnO)-based thin-film transistors(TFTs)are feasible with solution using various routes.Here,ZnO TFTs were fabricated via sol-gel method using zinc acetate as the starting reagent with different modifiers and solvents.The ZnO thin-film semiconductors with well-controlled,preferential crystal orientation and densely packed ZnO crystals can be prepared with the optimized fabrication conditions,exhibiting excellent field-effect far exceeding those of hydrogenated amorphous silicon(a-Si:H).However,the field-effect characteristics of ZnO TFTs were different for different precursor systems which were constituted by zinc acetate,modifiers and solvents.The co-modification of acetoin and monoethanolamine for the precursor system exhibited higher extent of crystal orientation and field-effect.The maximum mobility of 7.65 cm2V-1s-1 and current on-to-off ratio of^105–106 have been obtained.
