High density polyethylene filled with condutuctive carbon black was prepared by conventional meltmixing method. The effect of unidirectional pressure on the conductivity was studied. Wide angle X-ray diffraction （ WA...High density polyethylene filled with condutuctive carbon black was prepared by conventional meltmixing method. The effect of unidirectional pressure on the conductivity was studied. Wide angle X-ray diffraction （ WAXD ） was used to slum： the influence of pressure on the aggregate structure of the polymer filled with carbon black （CB） fillers. A model on the basis of the formation and destruction of conductive networks was proposed to explain the change in the conductivity with the application of pressure.展开更多
By means of impact abrasion tests, micro-hardness tests, and worn surface morphology observation via SEM, a comparison research based upon different impact abrasive wear conditions was conducted in this research to st...By means of impact abrasion tests, micro-hardness tests, and worn surface morphology observation via SEM, a comparison research based upon different impact abrasive wear conditions was conducted in this research to study the influence of different carbon contents(1.25 wt.%, 1.35 wt.%, and 1.45 wt.%) on the wear resistance and wear mechanism of water-quenched Mn13Cr2 and Mn18Cr2 cast steels. The research results show that the wear resistance of the Mn18Cr2 cast steel is superior to that of the Mn13Cr2 cast steel under the condition of the same carbon content and different impact abrasive wear conditions because the Mn18Cr2 cast steel possesses higher worn work hardening capacity as well as a more desirable combination of high hardness and impact toughness than that of the Mn13Cr2 cast steel. When a 4.5 J impact abrasive load is applied, the wear mechanism of both steels is that plastic deformation fatigue spalling and micro-cutting coexist, and the former dominates. When the carbon content is increased, the worn work hardening effect becomes increasingly dramatic, while the wear resistance of both steels decreases, which implies that an increase in impact toughness is beneficial to improving the wear resistance under severe impact abrasive wear conditions. Under the condition of a 1.0 J impact abrasive load, the wear mechanism of both steels is that plastic deformation fatigue spalling and micro-cutting coexist, and the latter plays a leading role. The worn work hardening effect and wear resistance intensify when the carbon content is increased, which implies that a higher hardness can be conducive to better wear resistance under low impact abrasive condition.展开更多
Carbon black （CB）/polymer composites with high refractive index （RI） were fabricated from poly（vinyl alcohol） （PVA） and covalently functionalized nano-CB （PVA-es-CB） by simple esterification reaction. Transm...Carbon black （CB）/polymer composites with high refractive index （RI） were fabricated from poly（vinyl alcohol） （PVA） and covalently functionalized nano-CB （PVA-es-CB） by simple esterification reaction. Transmission electron microscopy showed that tmifonn aggregates of PVA-es-CB nanoparticles with a size smaller than I00 nm formed in the nanocomposite films. Ellipsometric measurements indicated that the PVA-es-CB/PVA composite films had a RI in the range 1.520-1.598 linearly increased with the PVA-es-CB volume content. Theoretical equation based on Lorentz-Lorenz theory provided reasonably close estimation of the refractive indices to the experimentally observed values. The hybrid films also revealed relatively good surface planarity, thermal stability and optical transparency.展开更多
文摘High density polyethylene filled with condutuctive carbon black was prepared by conventional meltmixing method. The effect of unidirectional pressure on the conductivity was studied. Wide angle X-ray diffraction （ WAXD ） was used to slum： the influence of pressure on the aggregate structure of the polymer filled with carbon black （CB） fillers. A model on the basis of the formation and destruction of conductive networks was proposed to explain the change in the conductivity with the application of pressure.
基金financially supported by the China Guangdong Province Science and Technology Plan Project(Nos.2010B0903000592011A080802003+1 种基金2011B090400519and 2012B090600030)
文摘By means of impact abrasion tests, micro-hardness tests, and worn surface morphology observation via SEM, a comparison research based upon different impact abrasive wear conditions was conducted in this research to study the influence of different carbon contents(1.25 wt.%, 1.35 wt.%, and 1.45 wt.%) on the wear resistance and wear mechanism of water-quenched Mn13Cr2 and Mn18Cr2 cast steels. The research results show that the wear resistance of the Mn18Cr2 cast steel is superior to that of the Mn13Cr2 cast steel under the condition of the same carbon content and different impact abrasive wear conditions because the Mn18Cr2 cast steel possesses higher worn work hardening capacity as well as a more desirable combination of high hardness and impact toughness than that of the Mn13Cr2 cast steel. When a 4.5 J impact abrasive load is applied, the wear mechanism of both steels is that plastic deformation fatigue spalling and micro-cutting coexist, and the former dominates. When the carbon content is increased, the worn work hardening effect becomes increasingly dramatic, while the wear resistance of both steels decreases, which implies that an increase in impact toughness is beneficial to improving the wear resistance under severe impact abrasive wear conditions. Under the condition of a 1.0 J impact abrasive load, the wear mechanism of both steels is that plastic deformation fatigue spalling and micro-cutting coexist, and the latter plays a leading role. The worn work hardening effect and wear resistance intensify when the carbon content is increased, which implies that a higher hardness can be conducive to better wear resistance under low impact abrasive condition.
基金financially supported by the National Natural Science Foundation of China(No.50733001)Natural Science Foundation of Shanghai(No.11ZR1409500)Shanghai Key Laboratory Project(No.08DZ2230500)
文摘Carbon black （CB）/polymer composites with high refractive index （RI） were fabricated from poly（vinyl alcohol） （PVA） and covalently functionalized nano-CB （PVA-es-CB） by simple esterification reaction. Transmission electron microscopy showed that tmifonn aggregates of PVA-es-CB nanoparticles with a size smaller than I00 nm formed in the nanocomposite films. Ellipsometric measurements indicated that the PVA-es-CB/PVA composite films had a RI in the range 1.520-1.598 linearly increased with the PVA-es-CB volume content. Theoretical equation based on Lorentz-Lorenz theory provided reasonably close estimation of the refractive indices to the experimentally observed values. The hybrid films also revealed relatively good surface planarity, thermal stability and optical transparency.
