A double-layer aluminum consisting of an aluminum core and a shellof SiO2 and polyacrylic acid was synthesized.This modified aluminum was used to improve the corrosion resistance and dispersive property of aluminum in...A double-layer aluminum consisting of an aluminum core and a shellof SiO2 and polyacrylic acid was synthesized.This modified aluminum was used to improve the corrosion resistance and dispersive property of aluminum in waterborne media.TEM,FTIR,XPS,and EDX determination showed that PAA and SiO2 were coated on the surface of aluminum.Evolved hydrogen detection showed that the corrosion resistance of composite particle had been markedly improved.Maximum corrosion inhibition efficiency of SiO2 coated aluminum（SiO2@Al）was 95.1% while that of double-layer coated aluminum（PAA/SiO2@Al）was 98.8%.Meanwhile,polyacrylic acid layer improved the agglomeration of aluminum significantly.According to the dispersibility test,the particle size of 50% volume fraction [d（0.5）] of aluminum,SiO2@Aland PAA/SiO2@Alwere 42,53,and 34 μm,respectively.展开更多
The corrosion-protective performance of plasma-polymerized (PP) coatings on pretreated aluminum substrates has been investigated by cathodic polarization curve measurement. The surface composition and electronic prope...The corrosion-protective performance of plasma-polymerized (PP) coatings on pretreated aluminum substrates has been investigated by cathodic polarization curve measurement. The surface composition and electronic properties of the pretreated and PP film coated metal surfaces were also characterized by XPS and the temperature-programmed photoelectron emission (TPPE). A PP coating was prepared on the pretreated surfaces by plasma polymerization of a mixture of tetraethoxysilane (TEOS) monomer vapor and oxygen using a 13.56MHz radiofrequency generator. The polarization curve of PP film coated samples was measured in NaCl aqueous solution. The weight loss rate calculated from the value of the corrosion current of the curve was used to estimate the protective performance of the PP film coated samples. Argon plasma treatment of the metal surface gave much better corrosion-protective performance than pretreatments such as oxidation by heating in air and diamond scratching. The XPS analysis indicated that the silicon oxide assigned to SiO2 was formed on the PP film coated surface. The TPPE analysis revealed that the electron emission characteristics for the metal surfaces pretreated only were strongly influenced by the pretreatments, while all the PP film coated samples exhibited nearly the same electron emission trend with a much decreased intensity.展开更多
Syntheses and properties of aluminum and titanium complexes incorporating the pyrrole-imine ligands,N-((1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)methanimine(H2L^1)and 2-cyano-1H-pyrrole(HL^2),have been investigated.Ad...Syntheses and properties of aluminum and titanium complexes incorporating the pyrrole-imine ligands,N-((1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)methanimine(H2L^1)and 2-cyano-1H-pyrrole(HL^2),have been investigated.Addition of one equiv of H2L^1 to AlMe3 and AlEt3,respectively results in the formation of dinuclear complexes[Al2(L^1)2 Me2](1)and[Al2(L^1)2 Et2](2).Treatment of Ti(NMe2)4 with one equiv of HL^2 and two equiv of iPrOH or three equiv of BnOH results in the production of complexes[Ti(HL^3)2(OiPr)2](3)and[Ti2(HL^3)2(OBn)6](4)(H2L^3=N,N-dimethyl-1H-pyrrole-2-carboximid-amide).HL^3 anion is an intermediate which is in situ formed from the reaction of HL^2 and Ti(NMe2)4.The structures of 1~4 were characterized by single crystal X-ray diffraction.The catalytic properties of 1~4 toward ring-opening polymerization(ROP)ofε-caprolactone were studied.All of the compounds could effectively initiate the polymerization reactions with good activities.展开更多
The hydrolysis polymerization precipitation process of Al(III) was studied with pH titration method, and the prepared polyaluminum solutions were characterized by various experimental methods: acid depolymerization, t...The hydrolysis polymerization precipitation process of Al(III) was studied with pH titration method, and the prepared polyaluminum solutions were characterized by various experimental methods: acid depolymerization, timed complex-colorimetric procedure, ultrafiltration, X-ray diffraction and infrared absorption spectrum. The results showed that the chemical species transformation and distribution of Al(III) in the hydrolysis-polymerization process depended on B=(OH/Al) ratio, pH and other factors. By their structures, the chemical species can be divided into three categories of monomeric (Ala), polymeric (Alb), sol or gel precipitates (Alc) and the polymeric species may be further divided into three groups such as linear low polymer (Alb1), linear high polymer (Alb2) and high polymer with cyclic structure (Alb3). The nominal molecular weight of polymeric species obtained by ultrafiltration was about 1000-50000 and most of them failed into a range around 10000. A scheme for the chemical speciation model of Al(III) solution was suggested.展开更多
The effects of the calorimetric buffer solutions were investigated while the two colorimetric reactions of AI-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and t...The effects of the calorimetric buffer solutions were investigated while the two colorimetric reactions of AI-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and the pH of the solutions were also investigated. A timed complexatian colorimetric analysis method of Al-Fe-ferron in view of the total concentration of {AI + Fe} was then established to determine the species distribution of polymeric Al-Fe. The testing wavelength was recommended at 362 net and the testing pH value was 5. With a comparison of the ratios of n(Al)/n(Fe), the standard adsorption curves of the polymeric Al-Fe solutions were derived from the experimental results. Furthermore, the solutions' composition were carious in both the molar n(Al)/n(Fe) ratios, i.e. 0/0, 5/5, 9/1 and 0/10, and the concentrations associated with the total ( Al + Fe which ranged from 10(-5) to 10(-4) mol/L..展开更多
基金Funded by the National Natural Science Foundation of China(31170558)the Fundamental Research Funds for the Central Universities(410500006)
文摘A double-layer aluminum consisting of an aluminum core and a shellof SiO2 and polyacrylic acid was synthesized.This modified aluminum was used to improve the corrosion resistance and dispersive property of aluminum in waterborne media.TEM,FTIR,XPS,and EDX determination showed that PAA and SiO2 were coated on the surface of aluminum.Evolved hydrogen detection showed that the corrosion resistance of composite particle had been markedly improved.Maximum corrosion inhibition efficiency of SiO2 coated aluminum（SiO2@Al）was 95.1% while that of double-layer coated aluminum（PAA/SiO2@Al）was 98.8%.Meanwhile,polyacrylic acid layer improved the agglomeration of aluminum significantly.According to the dispersibility test,the particle size of 50% volume fraction [d（0.5）] of aluminum,SiO2@Aland PAA/SiO2@Alwere 42,53,and 34 μm,respectively.
文摘The corrosion-protective performance of plasma-polymerized (PP) coatings on pretreated aluminum substrates has been investigated by cathodic polarization curve measurement. The surface composition and electronic properties of the pretreated and PP film coated metal surfaces were also characterized by XPS and the temperature-programmed photoelectron emission (TPPE). A PP coating was prepared on the pretreated surfaces by plasma polymerization of a mixture of tetraethoxysilane (TEOS) monomer vapor and oxygen using a 13.56MHz radiofrequency generator. The polarization curve of PP film coated samples was measured in NaCl aqueous solution. The weight loss rate calculated from the value of the corrosion current of the curve was used to estimate the protective performance of the PP film coated samples. Argon plasma treatment of the metal surface gave much better corrosion-protective performance than pretreatments such as oxidation by heating in air and diamond scratching. The XPS analysis indicated that the silicon oxide assigned to SiO2 was formed on the PP film coated surface. The TPPE analysis revealed that the electron emission characteristics for the metal surfaces pretreated only were strongly influenced by the pretreatments, while all the PP film coated samples exhibited nearly the same electron emission trend with a much decreased intensity.
基金supported by the National Natural Science Foundation of China(21772140)Natural Science Foundation of Jiangsu Province(BK20171213)the Priority Academic Program Development of Jiangsu Higher Education Institution
文摘Syntheses and properties of aluminum and titanium complexes incorporating the pyrrole-imine ligands,N-((1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)methanimine(H2L^1)and 2-cyano-1H-pyrrole(HL^2),have been investigated.Addition of one equiv of H2L^1 to AlMe3 and AlEt3,respectively results in the formation of dinuclear complexes[Al2(L^1)2 Me2](1)and[Al2(L^1)2 Et2](2).Treatment of Ti(NMe2)4 with one equiv of HL^2 and two equiv of iPrOH or three equiv of BnOH results in the production of complexes[Ti(HL^3)2(OiPr)2](3)and[Ti2(HL^3)2(OBn)6](4)(H2L^3=N,N-dimethyl-1H-pyrrole-2-carboximid-amide).HL^3 anion is an intermediate which is in situ formed from the reaction of HL^2 and Ti(NMe2)4.The structures of 1~4 were characterized by single crystal X-ray diffraction.The catalytic properties of 1~4 toward ring-opening polymerization(ROP)ofε-caprolactone were studied.All of the compounds could effectively initiate the polymerization reactions with good activities.
文摘The hydrolysis polymerization precipitation process of Al(III) was studied with pH titration method, and the prepared polyaluminum solutions were characterized by various experimental methods: acid depolymerization, timed complex-colorimetric procedure, ultrafiltration, X-ray diffraction and infrared absorption spectrum. The results showed that the chemical species transformation and distribution of Al(III) in the hydrolysis-polymerization process depended on B=(OH/Al) ratio, pH and other factors. By their structures, the chemical species can be divided into three categories of monomeric (Ala), polymeric (Alb), sol or gel precipitates (Alc) and the polymeric species may be further divided into three groups such as linear low polymer (Alb1), linear high polymer (Alb2) and high polymer with cyclic structure (Alb3). The nominal molecular weight of polymeric species obtained by ultrafiltration was about 1000-50000 and most of them failed into a range around 10000. A scheme for the chemical speciation model of Al(III) solution was suggested.
基金TheNationalNaturalScienceFoundationofChina (No .2 96 770 0 4)
文摘The effects of the calorimetric buffer solutions were investigated while the two colorimetric reactions of AI-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and the pH of the solutions were also investigated. A timed complexatian colorimetric analysis method of Al-Fe-ferron in view of the total concentration of {AI + Fe} was then established to determine the species distribution of polymeric Al-Fe. The testing wavelength was recommended at 362 net and the testing pH value was 5. With a comparison of the ratios of n(Al)/n(Fe), the standard adsorption curves of the polymeric Al-Fe solutions were derived from the experimental results. Furthermore, the solutions' composition were carious in both the molar n(Al)/n(Fe) ratios, i.e. 0/0, 5/5, 9/1 and 0/10, and the concentrations associated with the total ( Al + Fe which ranged from 10(-5) to 10(-4) mol/L..
