In this study, the barite nanoparticles were successfully modified with stearate and the influence of stearate addition on the performance of barite nanoparticles was systematically investigated. The products were cha...In this study, the barite nanoparticles were successfully modified with stearate and the influence of stearate addition on the performance of barite nanoparticles was systematically investigated. The products were characterized by activating factor analysis, contact angle test, surface energy calculation, sedimentation rate calculation, rheological measurement, and FT-IR analysis, etc. As the quantity of added stearate increased, both the activating factor and contact angle of barite nanoparticles increased first then decreased. When the stearate content was 5% of the mass of barite nanoparticles, the activating factor and water contact angle of modified particles reached maximum value, 97% and 126% respectively. At this time, the sedimentation rate reached minimum, and so did the surface energy. The rheological test reveals that the viscosity of modified barite nanoparticles/petronol system decreases greatly, indicating the surface performance of barite nanoparticles has changed from hydrophilicity to lipophilicity after modification. C=O and COO stretching vibration peaks were found in the FT-IR spectra, which proves that the stearate has combined onto the surface of barite nanoparticles. Finally, according to the zeta potential result of unmodified barite, the possible modification mechanism was provided.展开更多
The surface of nano-TiO_2 was encapsulated with hydroxyl-propyl-methyl cellulose(HPMC),and then cograftedwith acrylates.Conditions of absorbing and grafting have been studied.Modified nano-TiO_2 particles were charact...The surface of nano-TiO_2 was encapsulated with hydroxyl-propyl-methyl cellulose(HPMC),and then cograftedwith acrylates.Conditions of absorbing and grafting have been studied.Modified nano-TiO_2 particles were characterized byFT-IR spectra,TEM and TG analysis.It was convinced from FT-IR studies that both methyl methacrylate(MMA)and butyl-methacrylate(BMA)were co-grafted onto the surface of nano-TiO_2 particles.TEM images show that the surface of nano-TiO_2 particles was successfully modified by a thick layer of film-like polymer.TG results demonstrate that the decompositiontemperature of HPMC-g-PMMA/PBMA,which has been grafted onto the surface of nano-TiO_2,is 56.9 K higher than that ofHPMC-g-PMMA/PBMA.展开更多
PEG （Polyethylene Glycol）-grafted nano-titania has been obtained in a one-step procedure using hexamethylene diisocyanate as the coupling agent and dibutyltin dilaurate as the catalyst in toluene at 80℃ and charact...PEG （Polyethylene Glycol）-grafted nano-titania has been obtained in a one-step procedure using hexamethylene diisocyanate as the coupling agent and dibutyltin dilaurate as the catalyst in toluene at 80℃ and characterized qualitatively by FTIR and quantitatively by elemental analysis and thermogravimetric analysis. A comparison of nano-titania with two other commonly used inorganic nanoparticles, nano-silica and nano-alumina, is made, revealing that reactivity order is nano- silica 〉 nano-alumina 〉 nano-titania in view of PEG grafting. Possible mechanism of PEG grafting is also discussed.展开更多
A general procedure for surface modification of nano-alumina using N, N＇-dicyclohexyl- carbodiimide （DCC） mediated amidation is reported. Aliphatic and aromatic carboxylic acids reacted smoothly with nano-alumina p...A general procedure for surface modification of nano-alumina using N, N＇-dicyclohexyl- carbodiimide （DCC） mediated amidation is reported. Aliphatic and aromatic carboxylic acids reacted smoothly with nano-alumina pretreated with 3-aminopropyltriethoxysilane in the presence of DCC, giving modified aluminas having organic surfaces. The grafted aluminas have been characterized qualitatively by FT-IR or ^13C CPMAS NMR spectroscopy, and quantitatively by thermogravimetric analysis and elemental analysis. The procedure was applied to polyether dendrons bearing carboxyl groups at the focal points, giving successful grafting of dendrimers onto nano-alumina.展开更多
Nano-TiO2 was coated with A12O3,SiO2 and silane coupling agent by chemical liquid deposition.The coating was characterized by Raman spectroscopy,XRD,TEM and FT-IR.The coating content and anti-ultraviolet capacity of n...Nano-TiO2 was coated with A12O3,SiO2 and silane coupling agent by chemical liquid deposition.The coating was characterized by Raman spectroscopy,XRD,TEM and FT-IR.The coating content and anti-ultraviolet capacity of nano-TiO2 were measured by XRF and UV-vis spectrometer.The results show that dense coatings containing 5% Al2O3 or SiO2 can be obtained by mixing slurry at pH 10,adding coating reagent and neutralization reagent into the slurry for 60 min at 85?95 ℃,and finally aging for 120 min.Noncrystal SiO2 was coated on the surface of nano-TiO2 to form silica gel polymer with a Ti—O—Si bond,while aluminum compound exists in the form of AlOOH and part Al(OH)3.The integrated dense film can shield photocatalysis effectively.The inorganic coating film can increase the wettability for xylene and stability in water.The surface modification of nano-TiO2 will not impair its ability for anti-ultraviolet radiation,and more short band ultraviolet radiation can be absorbed.In addition,the optimal coating amount of silane coupling agent should be less than 3% and the best wettability for xylene can be reached when the amount is 1.2%.展开更多
ZnO nanoparticles with an average size of 125 nm were prepared via homogeneous precipitation method and were characterized by SEM.The products were surface-modified by the surfactant SDS.Surface-modified nano particle...ZnO nanoparticles with an average size of 125 nm were prepared via homogeneous precipitation method and were characterized by SEM.The products were surface-modified by the surfactant SDS.Surface-modified nano particles were added at a mass ratio of 1.0%,2.0%,3.0%,and 4.0%,respectively,in base oil and their friction and wear behaviors were evaluated on a MRS-10D type four-ball wear tester.After four-ball wear tests,the morphology of the rubbing surfaces was evaluated with metallographic microscope.It was revealed that the modified nano ZnO had excellent behavior for improving anti-wear property and friction coefficient,which could greatly reduce the friction of machine parts.展开更多
The surface of nano SiO 2 was modified by being encapsulated with hydroxy propyl methyl cellulose (HPMC), and then co grafted with acrylates. The grafting conditions, such as pH of the medium, and initiator conce...The surface of nano SiO 2 was modified by being encapsulated with hydroxy propyl methyl cellulose (HPMC), and then co grafted with acrylates. The grafting conditions, such as pH of the medium, and initiator concentration have been studied. The modified nano SiO 2 particles were characterized by TEM, DSC and FT IR spectra. TEM images show that the surface of the nano particles has been successfully modified by a thick layer of film like polymer in this way. The DSC results show that the decomposition temperature of modified nano particles of SiO 2 is 90 ℃ higher than that of grafted on polymer. According to the FT IR spectra, it is convinced that poly methyl methacrylate (PMMA) and poly acrylic butyl ester (PBA) were co grafted onto the surface of nano SiO 2.展开更多
基金supported by the International Corporation Project (Grant No.07SU07001)the Science Foundation of Science and Technology Commission of Shanghai Municipality (Grant No.0552nm011)
文摘In this study, the barite nanoparticles were successfully modified with stearate and the influence of stearate addition on the performance of barite nanoparticles was systematically investigated. The products were characterized by activating factor analysis, contact angle test, surface energy calculation, sedimentation rate calculation, rheological measurement, and FT-IR analysis, etc. As the quantity of added stearate increased, both the activating factor and contact angle of barite nanoparticles increased first then decreased. When the stearate content was 5% of the mass of barite nanoparticles, the activating factor and water contact angle of modified particles reached maximum value, 97% and 126% respectively. At this time, the sedimentation rate reached minimum, and so did the surface energy. The rheological test reveals that the viscosity of modified barite nanoparticles/petronol system decreases greatly, indicating the surface performance of barite nanoparticles has changed from hydrophilicity to lipophilicity after modification. C=O and COO stretching vibration peaks were found in the FT-IR spectra, which proves that the stearate has combined onto the surface of barite nanoparticles. Finally, according to the zeta potential result of unmodified barite, the possible modification mechanism was provided.
基金This work was funded by the Natural Science Fund of Anhui Educational Committeethe Youth Fund of Anhui Normal University.
文摘The surface of nano-TiO_2 was encapsulated with hydroxyl-propyl-methyl cellulose(HPMC),and then cograftedwith acrylates.Conditions of absorbing and grafting have been studied.Modified nano-TiO_2 particles were characterized byFT-IR spectra,TEM and TG analysis.It was convinced from FT-IR studies that both methyl methacrylate(MMA)and butyl-methacrylate(BMA)were co-grafted onto the surface of nano-TiO_2 particles.TEM images show that the surface of nano-TiO_2 particles was successfully modified by a thick layer of film-like polymer.TG results demonstrate that the decompositiontemperature of HPMC-g-PMMA/PBMA,which has been grafted onto the surface of nano-TiO_2,is 56.9 K higher than that ofHPMC-g-PMMA/PBMA.
文摘PEG （Polyethylene Glycol）-grafted nano-titania has been obtained in a one-step procedure using hexamethylene diisocyanate as the coupling agent and dibutyltin dilaurate as the catalyst in toluene at 80℃ and characterized qualitatively by FTIR and quantitatively by elemental analysis and thermogravimetric analysis. A comparison of nano-titania with two other commonly used inorganic nanoparticles, nano-silica and nano-alumina, is made, revealing that reactivity order is nano- silica 〉 nano-alumina 〉 nano-titania in view of PEG grafting. Possible mechanism of PEG grafting is also discussed.
文摘A general procedure for surface modification of nano-alumina using N, N＇-dicyclohexyl- carbodiimide （DCC） mediated amidation is reported. Aliphatic and aromatic carboxylic acids reacted smoothly with nano-alumina pretreated with 3-aminopropyltriethoxysilane in the presence of DCC, giving modified aluminas having organic surfaces. The grafted aluminas have been characterized qualitatively by FT-IR or ^13C CPMAS NMR spectroscopy, and quantitatively by thermogravimetric analysis and elemental analysis. The procedure was applied to polyether dendrons bearing carboxyl groups at the focal points, giving successful grafting of dendrimers onto nano-alumina.
基金Project(2002126) supported by the Chongqing Science Committee,China
文摘Nano-TiO2 was coated with A12O3,SiO2 and silane coupling agent by chemical liquid deposition.The coating was characterized by Raman spectroscopy,XRD,TEM and FT-IR.The coating content and anti-ultraviolet capacity of nano-TiO2 were measured by XRF and UV-vis spectrometer.The results show that dense coatings containing 5% Al2O3 or SiO2 can be obtained by mixing slurry at pH 10,adding coating reagent and neutralization reagent into the slurry for 60 min at 85?95 ℃,and finally aging for 120 min.Noncrystal SiO2 was coated on the surface of nano-TiO2 to form silica gel polymer with a Ti—O—Si bond,while aluminum compound exists in the form of AlOOH and part Al(OH)3.The integrated dense film can shield photocatalysis effectively.The inorganic coating film can increase the wettability for xylene and stability in water.The surface modification of nano-TiO2 will not impair its ability for anti-ultraviolet radiation,and more short band ultraviolet radiation can be absorbed.In addition,the optimal coating amount of silane coupling agent should be less than 3% and the best wettability for xylene can be reached when the amount is 1.2%.
基金supported by Liaoning Provincial Office of Education for Innovation Team (Project number:2006T001)Liaoning Province of Key Laboratory Project (Project number:2008403001)
文摘ZnO nanoparticles with an average size of 125 nm were prepared via homogeneous precipitation method and were characterized by SEM.The products were surface-modified by the surfactant SDS.Surface-modified nano particles were added at a mass ratio of 1.0%,2.0%,3.0%,and 4.0%,respectively,in base oil and their friction and wear behaviors were evaluated on a MRS-10D type four-ball wear tester.After four-ball wear tests,the morphology of the rubbing surfaces was evaluated with metallographic microscope.It was revealed that the modified nano ZnO had excellent behavior for improving anti-wear property and friction coefficient,which could greatly reduce the friction of machine parts.
基金ProjectsupportedbytheNaturalScienceFoundationofAnhuiEducationalCommittee (No .2 0 0 1KJ0 96),theSpecialScienceResearchFoundationofAnhuiNormalUniversity (No .2000ZX10)andtheNaturalScienceImportantFoundationofAnhuiProvince (No .0 10 2 2 0 0 7)
文摘The surface of nano SiO 2 was modified by being encapsulated with hydroxy propyl methyl cellulose (HPMC), and then co grafted with acrylates. The grafting conditions, such as pH of the medium, and initiator concentration have been studied. The modified nano SiO 2 particles were characterized by TEM, DSC and FT IR spectra. TEM images show that the surface of the nano particles has been successfully modified by a thick layer of film like polymer in this way. The DSC results show that the decomposition temperature of modified nano particles of SiO 2 is 90 ℃ higher than that of grafted on polymer. According to the FT IR spectra, it is convinced that poly methyl methacrylate (PMMA) and poly acrylic butyl ester (PBA) were co grafted onto the surface of nano SiO 2.
