Using an MFT-R4000 tester at room temperature,the leaf-surface wax of two desert plants,Ammopiptanthus mongolicus(AM)and Reaumuria soongorica(RS),was extracted and evaluated for its potential as a lubricant additive i...Using an MFT-R4000 tester at room temperature,the leaf-surface wax of two desert plants,Ammopiptanthus mongolicus(AM)and Reaumuria soongorica(RS),was extracted and evaluated for its potential as a lubricant additive in polyalphaolefin(PAO)for steel-steel contact.Gas chromatography-mass spectrometry analysis was performed to identify the composition of the AM leaf-surface wax,and scanning electron microscopy and X-ray photoelectron spectroscopy were used to investigate its friction mechanisms.The results suggest that the leaf-surface wax could successfully reduce the friction and wear of steel-steel sliding pairs compared with PAO containing molybdenum dithiocarbamate additives.AM,in particular,showed high-performance wear resistance and friction-reducing properties.Its excellent tribological properties were attributed to the wax composition of leaf-surface fatty acids,alcohol,and esters.展开更多
Targeting the problem of available water conservation in sand fixation, the sand-fixing and grass-planting materials were prepared with clay modified by emulsifying vegetable waxes and octylphenol polyoxyethylene eth...Targeting the problem of available water conservation in sand fixation, the sand-fixing and grass-planting materials were prepared with clay modified by emulsifying vegetable waxes and octylphenol polyoxyethylene ether （OP4）. The water retention property was studied in simulating desertification environmental climate and the materials were characterized by means of UV-Vis, SEM, FTIR, XRD and TGA measurements. The experimental result showed that the materials had excellent water retention properties, due to that vegetable waxes adhered evenly to clay particle surfaces, made the clay pores changing from hydrophilic to hydrophobic and so inhibited the water evaporation. Grass-planting experiment showed that, with reasonable mass ratio of clay, vegetable waxes and surfactant, the materials not only inhibited water evaporation but also maintained sound air permeability so shat the germination rate and survival rate of grass were significantly improved.展开更多
Three kinds of leaf-surface waxes are extracted from the leaves of Euonymus japonicas(EJ), Sabina chinensis(SC) and Sabina procumbens(SP) to be tested for their tribological properties. Lubricating oils containing the...Three kinds of leaf-surface waxes are extracted from the leaves of Euonymus japonicas(EJ), Sabina chinensis(SC) and Sabina procumbens(SP) to be tested for their tribological properties. Lubricating oils containing these 3 waxes respectively were analyzed via gas chromatography-mass spectrometer(GC-MS) for their chemical constituents and tested with friction and wear testing machine and time of flight secondary ion mass spectrometry(TOF-SIMS) for the tribological mechanism. It was found that all the tested cuticular wax can reduce the coefficient of friction, and the waxes of SC and EJ can reduce the wear width. The contents of acid and esters in the wax can improve the friction reducing property by forming tribochemical films on the metal, but result in the increase of wear due to corrosion. The increase of ions containing C, H, O and the decline of aluminum positive ions on the worn surface,demonstrate that the tribofilms derived from long chain compounds play a role of protecting the metal surfaces.展开更多
基金The authors would like to thank the financial support for this work from the National Natural Science Foundation of China(No.51575181)。
文摘Using an MFT-R4000 tester at room temperature,the leaf-surface wax of two desert plants,Ammopiptanthus mongolicus(AM)and Reaumuria soongorica(RS),was extracted and evaluated for its potential as a lubricant additive in polyalphaolefin(PAO)for steel-steel contact.Gas chromatography-mass spectrometry analysis was performed to identify the composition of the AM leaf-surface wax,and scanning electron microscopy and X-ray photoelectron spectroscopy were used to investigate its friction mechanisms.The results suggest that the leaf-surface wax could successfully reduce the friction and wear of steel-steel sliding pairs compared with PAO containing molybdenum dithiocarbamate additives.AM,in particular,showed high-performance wear resistance and friction-reducing properties.Its excellent tribological properties were attributed to the wax composition of leaf-surface fatty acids,alcohol,and esters.
基金Funded by the National Natural Science Foundation of China(No.50772131)the Main Project of Ministry of Education of China(No.106086)the Fundamental Research Funds for the Central Universities of China University of Mining and Technology(Beijing)(No.2010YJ05)
文摘Targeting the problem of available water conservation in sand fixation, the sand-fixing and grass-planting materials were prepared with clay modified by emulsifying vegetable waxes and octylphenol polyoxyethylene ether （OP4）. The water retention property was studied in simulating desertification environmental climate and the materials were characterized by means of UV-Vis, SEM, FTIR, XRD and TGA measurements. The experimental result showed that the materials had excellent water retention properties, due to that vegetable waxes adhered evenly to clay particle surfaces, made the clay pores changing from hydrophilic to hydrophobic and so inhibited the water evaporation. Grass-planting experiment showed that, with reasonable mass ratio of clay, vegetable waxes and surfactant, the materials not only inhibited water evaporation but also maintained sound air permeability so shat the germination rate and survival rate of grass were significantly improved.
基金supported by the National Natural Science Foundation of China(Grant No.51575181)Beijing Natural Science Foundation(Grant No.2172053)
文摘Three kinds of leaf-surface waxes are extracted from the leaves of Euonymus japonicas(EJ), Sabina chinensis(SC) and Sabina procumbens(SP) to be tested for their tribological properties. Lubricating oils containing these 3 waxes respectively were analyzed via gas chromatography-mass spectrometer(GC-MS) for their chemical constituents and tested with friction and wear testing machine and time of flight secondary ion mass spectrometry(TOF-SIMS) for the tribological mechanism. It was found that all the tested cuticular wax can reduce the coefficient of friction, and the waxes of SC and EJ can reduce the wear width. The contents of acid and esters in the wax can improve the friction reducing property by forming tribochemical films on the metal, but result in the increase of wear due to corrosion. The increase of ions containing C, H, O and the decline of aluminum positive ions on the worn surface,demonstrate that the tribofilms derived from long chain compounds play a role of protecting the metal surfaces.
