A high alkali reactive aggregate zeolitization perlite was used to test the long term effectiveness of LiOH in inhibiting alkali silica reaction.In this paper,the rigorous conditions were designed that the mortar b...A high alkali reactive aggregate zeolitization perlite was used to test the long term effectiveness of LiOH in inhibiting alkali silica reaction.In this paper,the rigorous conditions were designed that the mortar bars had been cured at 80℃ for 3 years after autoclaved 24 hours at 150℃.Under this condition,LiOH was able to inhibit the alkali silica reaction long term effectiveness.Not only the relationship between the molar ratio of n(Li)/(Na) and the alkali contents in systems was established, but also the governing mechanism of such effects was also studied by SEM.展开更多
Rule of similarity and latex compounding techniques were combined for the first time to prepare natural rubber/nanosilica （NR/SiO2） nanocomposite with core-shell nanosilica-poly （methyl methacrylate） （SiO2-PMMA）...Rule of similarity and latex compounding techniques were combined for the first time to prepare natural rubber/nanosilica （NR/SiO2） nanocomposite with core-shell nanosilica-poly （methyl methacrylate） （SiO2-PMMA） particles and PMMA-modified natural rubber matrix （NR-PMMA）. The micro- structure of SiO2 and nanocomposites with different SiO2 contents was characterized by fourier transform infrared spectroscopy （FTIR）; the morphology of nanocomposites was investigated with scanning electron microscopy （SEM）; the tensile strength was characterized by tensile testing machine and the thermal stability of composites was studied by thermal gravimetric analysis. Results showed that PMMA chains have successfully grafted onto the surface of SiO2, and the core-shell SiO2-PMMA nanoparticles and NR-PMMA latex have been perfectly incorporated. SiO2-PMMA nanoparticles are evenly distributed over the NR matrix with an average size in the range of 60-100 nm at the low content （SiO2≤ 3 wt%）, while aggregations are apparently observed when 5 wt% SiO2 is loaded. In addition, NP/SiO2 composities possess a considerable improvement in ageing resistance compared with the pure NR. The tensile strength of composite increases from 6.99 to 12.72 MPa, reaching the highest value at a 0.5 wt% SiO2 loading, and then the figure decreases gradually because of the aggregation of SiO2 nanoparticles. It is anticipated that the reported process is to provide a simple and economic way for preparing NR composites.展开更多
A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO_2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydro-genation of aromatic compounds were studied. The ...A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO_2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydro-genation of aromatic compounds were studied. The results showed that this catalystcould catalyze the hydrogenation of phenol, anisol, p-cresol, benzene and toluene to cyclo-hexanol, cyclohexyl methyl ether, p-methyl cyclohexanol, cyclohexane and methylcyclo-hexane, respectively in 100% yield at 30℃ and 1 atm. In the hydrogenation of phenol,COO/Pt ratio in SiO_2-CMC-Pt has much influence on the initial hydrogenation rate andthe selectivity for the intermediate product, cyclohexanone. The highest initial rate andthe highest yield of cyclohexanone both occur at COO/Pt ratio of 6. The complex is stableduring the reaction and can be used repeatedly.展开更多
利用绿色非离子表面活性剂烷基糖苷APG08-10和阳离子表面活性剂十八烷基三甲基氯化铵1831为复合模板剂,正硅酸乙酯为硅源,导向制备出笼状介孔二氧化硅。通过氮气物理吸附、透射电镜对其结构进行表征,得到比表面积S BET 540.2 m^(2)/g,孔...利用绿色非离子表面活性剂烷基糖苷APG08-10和阳离子表面活性剂十八烷基三甲基氯化铵1831为复合模板剂,正硅酸乙酯为硅源,导向制备出笼状介孔二氧化硅。通过氮气物理吸附、透射电镜对其结构进行表征,得到比表面积S BET 540.2 m^(2)/g,孔容0.72 m 3/g,孔径3.8 nm,粒径90 nm左右的笼状介孔二氧化硅纳米材料。展开更多
文摘A high alkali reactive aggregate zeolitization perlite was used to test the long term effectiveness of LiOH in inhibiting alkali silica reaction.In this paper,the rigorous conditions were designed that the mortar bars had been cured at 80℃ for 3 years after autoclaved 24 hours at 150℃.Under this condition,LiOH was able to inhibit the alkali silica reaction long term effectiveness.Not only the relationship between the molar ratio of n(Li)/(Na) and the alkali contents in systems was established, but also the governing mechanism of such effects was also studied by SEM.
基金Funded by the National Natural Science Foundation of China(No.50763006)Ministry of Science and Technology R&D Research Institutes(No.2008EG134285)+1 种基金973 Program Special Fund(No.2010CB635109)the Fundamental Research Funds for Rubber Research Institute,CATAS(No.1630022012013)
文摘Rule of similarity and latex compounding techniques were combined for the first time to prepare natural rubber/nanosilica （NR/SiO2） nanocomposite with core-shell nanosilica-poly （methyl methacrylate） （SiO2-PMMA） particles and PMMA-modified natural rubber matrix （NR-PMMA）. The micro- structure of SiO2 and nanocomposites with different SiO2 contents was characterized by fourier transform infrared spectroscopy （FTIR）; the morphology of nanocomposites was investigated with scanning electron microscopy （SEM）; the tensile strength was characterized by tensile testing machine and the thermal stability of composites was studied by thermal gravimetric analysis. Results showed that PMMA chains have successfully grafted onto the surface of SiO2, and the core-shell SiO2-PMMA nanoparticles and NR-PMMA latex have been perfectly incorporated. SiO2-PMMA nanoparticles are evenly distributed over the NR matrix with an average size in the range of 60-100 nm at the low content （SiO2≤ 3 wt%）, while aggregations are apparently observed when 5 wt% SiO2 is loaded. In addition, NP/SiO2 composities possess a considerable improvement in ageing resistance compared with the pure NR. The tensile strength of composite increases from 6.99 to 12.72 MPa, reaching the highest value at a 0.5 wt% SiO2 loading, and then the figure decreases gradually because of the aggregation of SiO2 nanoparticles. It is anticipated that the reported process is to provide a simple and economic way for preparing NR composites.
文摘A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO_2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydro-genation of aromatic compounds were studied. The results showed that this catalystcould catalyze the hydrogenation of phenol, anisol, p-cresol, benzene and toluene to cyclo-hexanol, cyclohexyl methyl ether, p-methyl cyclohexanol, cyclohexane and methylcyclo-hexane, respectively in 100% yield at 30℃ and 1 atm. In the hydrogenation of phenol,COO/Pt ratio in SiO_2-CMC-Pt has much influence on the initial hydrogenation rate andthe selectivity for the intermediate product, cyclohexanone. The highest initial rate andthe highest yield of cyclohexanone both occur at COO/Pt ratio of 6. The complex is stableduring the reaction and can be used repeatedly.
文摘利用绿色非离子表面活性剂烷基糖苷APG08-10和阳离子表面活性剂十八烷基三甲基氯化铵1831为复合模板剂,正硅酸乙酯为硅源,导向制备出笼状介孔二氧化硅。通过氮气物理吸附、透射电镜对其结构进行表征,得到比表面积S BET 540.2 m^(2)/g,孔容0.72 m 3/g,孔径3.8 nm,粒径90 nm左右的笼状介孔二氧化硅纳米材料。
