The effect of chemically reduced graphene oxide （CRGO） on the phase separation behavior of poly（methyl methacrylate）/poly（styrene-co-acrylonitrile） （PMMA/SAN） blends and the simultaneous response of rheologica...The effect of chemically reduced graphene oxide （CRGO） on the phase separation behavior of poly（methyl methacrylate）/poly（styrene-co-acrylonitrile） （PMMA/SAN） blends and the simultaneous response of rheological and conductive behavior of PMMA/SAN/CRGO nanocomposites upon annealing above the phase-separation temperatures were investigated. The introduction of CRGO causes the decrease of binodal temperature and the increase of spinodal temperature for PMMA/SAN blends and then enlarges their metastable regime. During annealing, the well-dispersed CRGO in the homogeneous blend matrix tends to be selectively located in the SAN-rich phase with the evolution of phase separation and then the CRGO further agglomerates effectively in the SAN-rich phase to form the conductive pathway. Thermal-induced dynamic percolation is observed for both the resistivity p and dynamic storage modulus G＇ as a function of annealing time. The resistivity variation is ascribed to the agglomeration of CRGO in the SAN-rich phase, while the modulus evolution is attributed to the combined contribution of phase separation for blend matrix and the agglomeration of CRGO in the SAN-rich phase.展开更多
Electrostatic separation is one of the mineral processing methods based on mineral conductivity.This method has some significant problems such as being sensitive to humidity,high middling product,and impurity of non-c...Electrostatic separation is one of the mineral processing methods based on mineral conductivity.This method has some significant problems such as being sensitive to humidity,high middling product,and impurity of non-conductive minerals.In this study,a new pretreatment method was proposed for the separation of zircon from quartz before electrostatic separation to solve these disadvantages.In this regard,two stages of pretreatment were applied which involved using collector of sodium dodecyl sulfate(SDS)for adjusting wettability of the zircon surface and spraying electrolyte aqueous solution to increase conductivity of the quartz surface.The effects of important parameters including pH,collector concentration,conditioning time,and concentration and type of electrolyte on the process efficiency were evaluated.The results showed that the optimal conditions of high-tension electrical separation were pH of 4,SDS concentration of 1×10-4 mol/L,conditioning time of 4 min and NaCl as an electrolyte with concentration of 4.27 mol/L.Separation efficiency of 95.12% was achieved in optimum conditions.This pretreatment method can be successfully used before high-tension electrical separation to separate the conductive or non-conductive minerals with various compositions.展开更多
Thin palladium composite membranes were prepared by modified electroless plating method on a-alumina supports and a dense Pd/α-Al2O3 composite membrane with high hydrogen flux, good selectivity for hydrogen was obtai...Thin palladium composite membranes were prepared by modified electroless plating method on a-alumina supports and a dense Pd/α-Al2O3 composite membrane with high hydrogen flux, good selectivity for hydrogen was obtained. It was tested in a single gas permeation system for hydrogen permeance and hydrogen selectivity over mtrogen. The hydrogen permeance of the corresponding membrane was ashigh as 2.45×10^-6mol·m^-2·s^-1.Pa^-1 and H2/N2 selectivityover700 at 623K and a pressure difference of 0.1MPa. The-main resistance of the composite membrane to H2 permeation lies in the aluminum ceramic support rather than the thin Pd layer.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51273173 and 51003093)the Research Foundation of Education Bureau of Zhejiang Province(No.Y200908238)
文摘The effect of chemically reduced graphene oxide （CRGO） on the phase separation behavior of poly（methyl methacrylate）/poly（styrene-co-acrylonitrile） （PMMA/SAN） blends and the simultaneous response of rheological and conductive behavior of PMMA/SAN/CRGO nanocomposites upon annealing above the phase-separation temperatures were investigated. The introduction of CRGO causes the decrease of binodal temperature and the increase of spinodal temperature for PMMA/SAN blends and then enlarges their metastable regime. During annealing, the well-dispersed CRGO in the homogeneous blend matrix tends to be selectively located in the SAN-rich phase with the evolution of phase separation and then the CRGO further agglomerates effectively in the SAN-rich phase to form the conductive pathway. Thermal-induced dynamic percolation is observed for both the resistivity p and dynamic storage modulus G＇ as a function of annealing time. The resistivity variation is ascribed to the agglomeration of CRGO in the SAN-rich phase, while the modulus evolution is attributed to the combined contribution of phase separation for blend matrix and the agglomeration of CRGO in the SAN-rich phase.
文摘Electrostatic separation is one of the mineral processing methods based on mineral conductivity.This method has some significant problems such as being sensitive to humidity,high middling product,and impurity of non-conductive minerals.In this study,a new pretreatment method was proposed for the separation of zircon from quartz before electrostatic separation to solve these disadvantages.In this regard,two stages of pretreatment were applied which involved using collector of sodium dodecyl sulfate(SDS)for adjusting wettability of the zircon surface and spraying electrolyte aqueous solution to increase conductivity of the quartz surface.The effects of important parameters including pH,collector concentration,conditioning time,and concentration and type of electrolyte on the process efficiency were evaluated.The results showed that the optimal conditions of high-tension electrical separation were pH of 4,SDS concentration of 1×10-4 mol/L,conditioning time of 4 min and NaCl as an electrolyte with concentration of 4.27 mol/L.Separation efficiency of 95.12% was achieved in optimum conditions.This pretreatment method can be successfully used before high-tension electrical separation to separate the conductive or non-conductive minerals with various compositions.
基金Supported by the National Natural Science Foundation of China （No.20425619）.
文摘Thin palladium composite membranes were prepared by modified electroless plating method on a-alumina supports and a dense Pd/α-Al2O3 composite membrane with high hydrogen flux, good selectivity for hydrogen was obtained. It was tested in a single gas permeation system for hydrogen permeance and hydrogen selectivity over mtrogen. The hydrogen permeance of the corresponding membrane was ashigh as 2.45×10^-6mol·m^-2·s^-1.Pa^-1 and H2/N2 selectivityover700 at 623K and a pressure difference of 0.1MPa. The-main resistance of the composite membrane to H2 permeation lies in the aluminum ceramic support rather than the thin Pd layer.
