The properties of styrene-butadiene rubber (SBR) reinforced by modified silica was investigated according to national standards. Silica was modified by silane coupling agents KH-570, KH-590, and KH-792. The optimized ...The properties of styrene-butadiene rubber (SBR) reinforced by modified silica was investigated according to national standards. Silica was modified by silane coupling agents KH-570, KH-590, and KH-792. The optimized geome-tries of molecular modified silica reinforced SBR were obtained by using B3LYP calculation of density functional theory with the 6-31+G basis sets. The natural bond orbital analyses were carried out. The Si—O bond length of silica modified by KH-792 was the shortest and the electronegative of O was the highest. It indicated that the connection between silica and KH-792 was the tightest. Higher tensile strength and elongation of reinforced SBR was obtained by silica modified with the KH-792. It was caused by large delocalization of lone pair electrons of the two N atoms in KH-792. The S—C bond length in silica modified by KH-590 was longer than the ordinary S—C bond length. Then the sulfur free radical (·S·) was produced more easily in vulcanization. The degree of crosslink was increased by the cross-linkage of the rubber molecule and the sulfur free radical. That was why the highest stress and tear strength of reinforced SBR was produced when silane coupling agent KH-590 was used. The calculation results was in accord with experimental data.展开更多
A flame retardant containing multiple antiflaming elements usually exhibits high-efficient flame retardancy. Here, a novel P/N/Si-containing ammonium polyphosphate derivative(APTES-APP) is synthesized from ammonium po...A flame retardant containing multiple antiflaming elements usually exhibits high-efficient flame retardancy. Here, a novel P/N/Si-containing ammonium polyphosphate derivative(APTES-APP) is synthesized from ammonium polyphosphate(APP) and silane coupling agent(3-aminopropyl)triethoxysilane(APTES)via cation exchange, which is quite different in the chemical structure from APTES-modified APP for retaining silicon hydroxyls. APTES-APP is highly efficient for the epoxy resin. 8%(mass) APTES-APP imparts excellent flame retardancy to the epoxy resin, with a V-0 rating at the UL-94 test(1.6 mm)and an LOI value of 26%(vol). The peak heat release rate and total smoke production of the flameretardant epoxy resin are decreased by 68.1% and 31.3%, respectively. The synergy of P/N/Si contributes to the well-expanded char residue with a strong and dense surface layer, which is a very good barrier against heat and mass transfer. Besides, there is no significant deterioration in the mechanical properties of flame-retardant epoxy resin thanks to silicon hydroxyls forming hydrogen bonds with epoxy molecules. Meanwhile, other molecules can be grafted onto APTES-APP via these silicon hydroxyls, if needed.Briefly, this work has developed a new strategy for amino silane as flame retardants. In conjunction with a low-cost and simple preparation method, APTES-APP has a promising prospect in the high-performance flame-retardant epoxy.展开更多
The influence of silane coupling agent on the film forming of galvanized steel treated with cerium salt was studied by scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）, and the corrosi...The influence of silane coupling agent on the film forming of galvanized steel treated with cerium salt was studied by scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）, and the corrosion resistance of conversion films was analyzed by electro interstitial scanning （EIS）. The results show that silane coupling agent KH-570 has significant influence on the compactness and homogeneity of cerium conversion films, and the process of film forming is promoted by increasing the content of tervalent and tetravalent cerium oxide. The impedance value of the cerium conversion film, especially modified with KH-570, is greater than that of the base metal, which reveals that it is necessary to add silane coupling agent to the film-forming solution in order to improve the corrosion resistance of the conversion film.展开更多
Polyurethane/desulfurization ash(PU/DA)composites were synthesized using"one-pot method",with the incorporation of a silane coupling agent(KH550)as a"molecular bridge"to facilitate the integration ...Polyurethane/desulfurization ash(PU/DA)composites were synthesized using"one-pot method",with the incorporation of a silane coupling agent(KH550)as a"molecular bridge"to facilitate the integration of DA as hard segments into the PU molecular chain.The effects of DA content(φ)on the mechanical properties,thermal stability,and hydrophobicity of PU,both before and after the addition of KH550,were thoroughly examined.The results of microscopic mechanism analysis confirmed that KH550 chemically modified the surface of DA,facilitating its incorporation into the polyurethane molecular chain,thereby significantly enhancing the compatibility and dispersion of DA within the PU matrix.When the mass fraction of modified DA(MDA)reached 12%,the mechanical properties,thermal stability,and hydrophobicity of the composites were substantially improved,with the tensile strength reaching 14.9 MPa,and the contact angle measuring 100.6°.展开更多
The reaction of ZnO nanoparticles grafted with KH570 silane coupling agent was carried out in water-alcohol mixed solvent. Several characterization methods were applied to analyzing the results of surface modification...The reaction of ZnO nanoparticles grafted with KH570 silane coupling agent was carried out in water-alcohol mixed solvent. Several characterization methods were applied to analyzing the results of surface modification such as Soxhlet extraction, Fourier transform infrared spectroscopy （FT-IR）, transmission electron microscopy （TEM）, thermogravimetry （TG）, differential scanning calorimetry （DSC） and zeta potential （ζ）. The results of FT-IR and TG-DSC show that the desired reaction chains have been covalently bonded on the surface of ZnO nanoparticles. Zetasizer results reveal that the maximal absolute value of ζ of the modified ZnO particles in acetone medium was 67.0 mV, which was much higher than that of the unmodified ZnO particles. So the surface of nanosized ZnO changed from hydrophilicity to hydrophobicity and the dispersity of ZnO nanoparticles were improved simultaneously. Finally, the mechanism of graft modification was discussed.展开更多
In order to reduce the agglomeration of nanographene and improve its dispersibility,six silane coupling agents were used to modify the surface of the nanographene particles.Visual inspection,Fourier-transform infrared...In order to reduce the agglomeration of nanographene and improve its dispersibility,six silane coupling agents were used to modify the surface of the nanographene particles.Visual inspection,Fourier-transform infrared spectroscopy,transmission electron microscopy,Raman spectroscopy,and X-ray diffraction were employed to evaluate the dispersion properties of the resulting graphene in an aqueous solution of silane coupling agents.Results show that all six types of silane coupling agents are efficient in promoting the dispersion of graphene in aqueous solutions,and no obvious sedimentation of the graphene dispersion solution is observed after a stationary storage period of 30 d.Taking 3-aminopropyltriethoxysilane(KH-550)as an example,after the graphene is dispersed in the KH-550 aqueous solution,the carboxyl group on the surface of the graphene reacts with the KH-550 amino group to form an amide bond,and KH-550 is successfully grafted onto the graphene surface.Polar functional groups ionize in water,creating an electrostatic repulsion effect,or hydrophilic functional groups form hydrogen bonds with water molecules,which is believed to improve the dispersion stability of graphene.The dispersed graphene is curled and contains many folds.Each fold has about three or four layers,with an interlayer spacing of about 0.65 nm.The dispersed graphene also has a complete lattice and a reduced number of defects.Nanographene disperses well in silane coupling agent aqueous solutions and can,therefore,be used to prepare cement-based composites.展开更多
We experimentally studied the fine lightweight aggregate with the particle size range of 3.15-4.75 mm used as functional bridge between FRP sheet and concrete substrate. However, problems would appear and how to deal ...We experimentally studied the fine lightweight aggregate with the particle size range of 3.15-4.75 mm used as functional bridge between FRP sheet and concrete substrate. However, problems would appear and how to deal with the interfacial transition zone（ITZ） and make it stronger is the key point for this concept. Considering that silane coupling agent（SCA） can provide a better bond on a silicon-containing material surface, it was introduced as a modifying material to further improve the bond quality of the ITZ between lightweight aggregate and cement paste. Results indicated that the water absorptivity of lightweight aggregate can be controlled by SCA solutions, and the pull-off bond strength, mechanical strength, and microhardness were increased, which was attributed to the optimized microstructure under the condition of an appropriate concentration of SCA.展开更多
The surface modification of clay fines was carried out by using silanecoupling agent. By means of IR spectra etc, a study was made on the combined state ofcoupling agent and clay. A rubber--clay composite material wit...The surface modification of clay fines was carried out by using silanecoupling agent. By means of IR spectra etc, a study was made on the combined state ofcoupling agent and clay. A rubber--clay composite material with excellent performancehas been prepared.展开更多
We used silane coupling agents to improve the bonding ability between wheat straw particles and UF resin, and investigated surface properties （wettability and surface roughness） and hardness of parti-cleboard made f...We used silane coupling agents to improve the bonding ability between wheat straw particles and UF resin, and investigated surface properties （wettability and surface roughness） and hardness of parti-cleboard made from UF-bonded wheat straw （Triticum aestivum L.） combined with poplar wood as affected by silane coupling agent content and straw/poplar wood particle ratios. We manufactured one-layered particleboard panels at four different ratios of straw to poplar wood par-ticles （0%, 15%, 30% and 45% wheat straw） and silane coupling agent content at three levels of 0, 5% and 10%. Roughness measurements, average roughness （Ra）, mean peak-to-valley height （Rz）, and root mean square roughness （Rq） were measured on unsanded samples by using a fine stylus tracing technique. We obtained contact angle measurements by using a goniometer connected to a digital camera and computer sys-tem. Boards containing greater amounts of poplar particles had superior hardness compared to control samples and had lower wettability. Panels made with higher amounts of silane had lower Rq values.展开更多
A novel silane coupling agent bearing sulfobetaine group, N,N-diethyl-N-（3-sulfopropyl）-aminopropyl- trimethoxysilane （DESATS）, was first designed, synthesized and characterized. Its solution property was studied ...A novel silane coupling agent bearing sulfobetaine group, N,N-diethyl-N-（3-sulfopropyl）-aminopropyl- trimethoxysilane （DESATS）, was first designed, synthesized and characterized. Its solution property was studied by means of dynamic light scattering. DESATS was successfully bonded onto the surface of the glass and proved by ESCA. Platelet adhesion assay in vitro indicated that the nonthrombogenicity of glass slide modified with DESATS is greatly improved.展开更多
A new kind of silane coupling agent, N- (β-aminoethyl ) - γ-aminopropyl triet hoxysilane, was used for DNA direct attachment on the surfaces of glass supports, then the immobilized DNA was hybridized with horseradis...A new kind of silane coupling agent, N- (β-aminoethyl ) - γ-aminopropyl triet hoxysilane, was used for DNA direct attachment on the surfaces of glass supports, then the immobilized DNA was hybridized with horseradish peroxidase (HRP)-labeled probe, and detected by using enhanced chemiluminescent method. In comparison with γ-aminopropyl triethoxysilane, the detection limits (S/N) of DNA were 10 pg and 75 pg respectively. Several experimental conditions of DNA attachING to glass supports were investigated, and the system of hybridization of nucleic acid on the surfaces of glass supports was developed.展开更多
To improve corrosion inhibition performance of copper foil with a novel two-step electrochemical modification processes,the surface of 35μm copper foils was coated with graphene oxide(GO)via electrochemical method at...To improve corrosion inhibition performance of copper foil with a novel two-step electrochemical modification processes,the surface of 35μm copper foils was coated with graphene oxide(GO)via electrochemical method at first step,then was further coated with 3-aminopropyltrimethoxysilane(APTS)at the second step.For the first step the copper foil acted as anode,and as cathode for the second one(we labeled it as E-GO).Optimum coating parameters for the preparation of E-GO coating are 5 V and 1 min with ratio of APTS/deionized water(DI)1.5/98.5(v/v).The physicochemical properties of modified coating were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM)and hydrophilicity test.Electrochemical behavior of different samples were also investigated.The experimental results indicate that anti-corrosion performance is significantly improved with two-step modified coating.And E-GO coating shows more positive corrosion potential and the highest corrosion resistance rate than others according to the Tafel curve.It is also found that surface hydrophobicity of E-GO coating is significantly improved.展开更多
Aim To determine the effect of silane grafted polypropylene on the property of different filler/polypropylene composites. Methods Polypropylene (PP) composites filled with talc(Ta), baryta sulfate and calcium carbonat...Aim To determine the effect of silane grafted polypropylene on the property of different filler/polypropylene composites. Methods Polypropylene (PP) composites filled with talc(Ta), baryta sulfate and calcium carbonate coupled with silane grafted polypropylene (PP-g-Si) were made, their mechanical properties and thermal properties were investigated, respectively. Results As compared with the non-coupled composites, the mechanical properties of PP/Ta/PP-g-Si composites were improved to some extent, though the values of tensile modulus and the strain at peak were decreased. But for PP/BaSO4 and PP/CaCO3 composites, the values of their mechanical properties varied slightly or even decreased with increasing PP-g-Si content within the experimental component. Meanwhile, PP-g-Si also affected the melting and crystallization behavior of PP in the composites. Conclusion PP-g-Si offers compatibilization in PP/Ta composites, but offers no-compatibilization in PP/BaSO4 and PP/CaCO3 composites within the extent of the present range of PP-g-Si, which shows that PP-g-Si can be used as the macromolecular coupling agent of PP and Ta composite.展开更多
The surface treatment of silca fume with silane coupling agent prior w incorporation in a cement mortar resulted in composites exhibiting increuses in loss tangent by 5%-200% and storage modulus by 10%-20% , relative...The surface treatment of silca fume with silane coupling agent prior w incorporation in a cement mortar resulted in composites exhibiting increuses in loss tangent by 5%-200% and storage modulus by 10%-20% , relative to the value obtained by using as-received silica fume. The scanning electron microscopy （SEM） images iindicate that there is a morphological difference in the cement paste with treated and as-received silica fume, The, X-ray diffraction （XRD）, infrared （IR） spectrum analyses and mercury intrusion porosimetry （ MIP ） have provided evidence to understand the reaction mechanism between treated silica .fume and the hydrate product of cement. This has led to the establishment of an initial microscopic model describing the damping behavior of cement matrix.展开更多
A novel surface treatment method using 3-aminopropyltriethoxysilane （AMPTES）, was developed to immobilize the fluorescein molecule on nano-HAP （nanometer hydroxyapatite） powders. By pretreating the nano-HAP powder...A novel surface treatment method using 3-aminopropyltriethoxysilane （AMPTES）, was developed to immobilize the fluorescein molecule on nano-HAP （nanometer hydroxyapatite） powders. By pretreating the nano-HAP powders surface with AMPTES, fluorescein, chosen on the basis of the chemical structure of the nano- HAP powders, could be bound to the nano-HAP powders surface. The chemical compositions of nano-HAP before and after being labeled were characterized by Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectron spectroscopy （XPS）. The morphology, phase composition, and the fluorescence characteristics of the nano-HAP powders with and without staining were also investigated. The FTIR and XPS results revealed that fluorescein had been successfully immobilized on the surface of AMPTES-bound nano-HAP powders via the acylamide bond formation between the -COOH of fluorescein and the -NH2 of AMPTES. The labeled nano-HAP powders possessed strong fluorescent intensity with a little deviation from the maximum emission wavelength of fluorescein. But the morphology and phase composition had no obvious alteration. Under fluorescence microscopy, the labeled nano-HAP powders, even after 24 h cell incubation, exhibited strong fluorescence.展开更多
Based on the difference of the Y-terminal functional group of the silane coupling agent(Y-Si(X)_(3)),four different silane coupling agents were employed to pretreat the surface of the NdFeB powders.The effects of sila...Based on the difference of the Y-terminal functional group of the silane coupling agent(Y-Si(X)_(3)),four different silane coupling agents were employed to pretreat the surface of the NdFeB powders.The effects of silane coupling agents on the flowability and compressibility of compounds for preparing bonded NdFeB magnets were studied.It is indicated that compounds pretreated by silane coupling agents have weaker friction and meshing force.The apparent density is increased by 0.3 g/cm^(3 )compared with the compound without silane coupling agent,and the radial crushing strength is significantly increased by about 3-4 times.In addition,the epoxy resin is more evenly distributed on the surface of the compounds treated by silane coupling agents observed by scanning electron microscopy,and some agglomerated particles are produced.Also,the compressibility of compounds with silane coupling agents is significantly improved due to the fact that hardening exponents are reduced.However,the addition of silane coupling agents has almost no effect on the magnetic properties of bonded magnets.The special energy was used to manifest the flowability of magnetic powder particles representing the macroscopic performance of the force between powder particles,providing a new direction for the study of the interface compatibility of two-phase or multiphase composite materials.展开更多
Nano-SiO2/polypropylene composite was prepared by melt-blending process. The nano-SiO2 particles were organized by wet process surface treatment with silane coupling agent KH-570. The effect of mass fraction of nano-S...Nano-SiO2/polypropylene composite was prepared by melt-blending process. The nano-SiO2 particles were organized by wet process surface treatment with silane coupling agent KH-570. The effect of mass fraction of nano-SiO2 particles and dosage of KH-570 on the toughening and strengthening of PP matrix were investigated based on the fractography of impact notch and the analysis of crystal structure by X-ray and dispersive structure of nano-SiO2 by TEM. Results show that the impact and flexural strength and modulus of the composite are improved obviously with low loading of nano-SiO2 （3 wt%-5 wt%）, and the izod impact strength of PP increases twice with 4 wt% nano-SiO2. The nano-SiO2 particles treated can disperse into the matrix resin, which has evident heterogeneous nucleation effects on the crystallization of PP. The optimal toughening and strengthening effects of PP matrix can be obtained when the content of nano-SiO2 and KH-570 are 4 wt% and 3 wt%, respectively.展开更多
Palygorskite （PGS） and vinyl tris-（2-methoxyethoxy） silane （KH-172） modified palygorskite （OPGS） were used to prepare acrylonitrile-butadiene-styrene （ABS）/clay composites. Thermal stability of the composite...Palygorskite （PGS） and vinyl tris-（2-methoxyethoxy） silane （KH-172） modified palygorskite （OPGS） were used to prepare acrylonitrile-butadiene-styrene （ABS）/clay composites. Thermal stability of the composites was evaluated by using thermogravimetric analysis （TGA）. The morphology of the fractured surface and the degree of dispersion of the clay in the ABS matrix were observed by scanning electron microscopy （SEM）. X-ray diffraction （XRD） analysis results showed the variation of the crystal structure. Measurements of the tensile properties of the ABS/clay composites proved that the ABS/OPGS composited material represented the most excellent tensile property, because of good compatibility and dispersion of ABS with OPGS.展开更多
The chemical composition and high wear resistance of steel slag(SS)make it a potential alternative to traditional inorganic fillers.3-Aminopropyltriethoxysilane(KH550)modified steel slag(MSS)was successfully prepared,...The chemical composition and high wear resistance of steel slag(SS)make it a potential alternative to traditional inorganic fillers.3-Aminopropyltriethoxysilane(KH550)modified steel slag(MSS)was successfully prepared,and its application in epoxy(EP)anti-corrosion coating was introduced.Due to the grafting of silane coupling agent functional groups onto the surface of SS,MSS exhibited improved solubility in xylene organic solvent and reduced agglomeration.When the MSS content was 15 wt.%,the contact angle of the MSS/EP composite coating was 101°,and the abrasion was only 0.07 g,compared with 56.2°and 0.13 g,respectively,for the pure EP coating.The corrosion resistance of coatings was investigated by performing the electrochemical test(impedance)after immersion in a 3.5 wt.%NaCl solution.The electrochemical test results showed that the impedance modulus of the 15 wt.%MSS/EP composite coating at low frequency(Z_(f)=0.01 Hz)was approximately 1.08×10^(7)Ωcm^(2),which was two orders of magnitude higher than that of the pure EP coating.展开更多
Ag_(3)PO_(4)exhibits a high photocatalytic activity if exposed to visible light,however,it displays bottlenecks such as poor cycle-stability and mediocre ability to degrade methyl orange(MO)because of limited adsorpti...Ag_(3)PO_(4)exhibits a high photocatalytic activity if exposed to visible light,however,it displays bottlenecks such as poor cycle-stability and mediocre ability to degrade methyl orange(MO)because of limited adsorption of MO molecules onto its surface.In this study,nano TiO_(2)prepared by a one-step method was combined with Ag_(3)PO_(4)to form a TiO_(2)@Ag_(3)PO_(4)heterojunction in order to improve this material both in terms of photocatalysis and photostability.After adding a KH-570 silane coupling agent,the photocatalytic performance of TiO_(2)@Ag_(3)PO_(4)could be improved even further,with the degradation rate of MO maintained at more than 90%after three cycles of visible in light.展开更多
文摘The properties of styrene-butadiene rubber (SBR) reinforced by modified silica was investigated according to national standards. Silica was modified by silane coupling agents KH-570, KH-590, and KH-792. The optimized geome-tries of molecular modified silica reinforced SBR were obtained by using B3LYP calculation of density functional theory with the 6-31+G basis sets. The natural bond orbital analyses were carried out. The Si—O bond length of silica modified by KH-792 was the shortest and the electronegative of O was the highest. It indicated that the connection between silica and KH-792 was the tightest. Higher tensile strength and elongation of reinforced SBR was obtained by silica modified with the KH-792. It was caused by large delocalization of lone pair electrons of the two N atoms in KH-792. The S—C bond length in silica modified by KH-590 was longer than the ordinary S—C bond length. Then the sulfur free radical (·S·) was produced more easily in vulcanization. The degree of crosslink was increased by the cross-linkage of the rubber molecule and the sulfur free radical. That was why the highest stress and tear strength of reinforced SBR was produced when silane coupling agent KH-590 was used. The calculation results was in accord with experimental data.
基金financially supported by the National Natural Science Foundation of China (22178242)。
文摘A flame retardant containing multiple antiflaming elements usually exhibits high-efficient flame retardancy. Here, a novel P/N/Si-containing ammonium polyphosphate derivative(APTES-APP) is synthesized from ammonium polyphosphate(APP) and silane coupling agent(3-aminopropyl)triethoxysilane(APTES)via cation exchange, which is quite different in the chemical structure from APTES-modified APP for retaining silicon hydroxyls. APTES-APP is highly efficient for the epoxy resin. 8%(mass) APTES-APP imparts excellent flame retardancy to the epoxy resin, with a V-0 rating at the UL-94 test(1.6 mm)and an LOI value of 26%(vol). The peak heat release rate and total smoke production of the flameretardant epoxy resin are decreased by 68.1% and 31.3%, respectively. The synergy of P/N/Si contributes to the well-expanded char residue with a strong and dense surface layer, which is a very good barrier against heat and mass transfer. Besides, there is no significant deterioration in the mechanical properties of flame-retardant epoxy resin thanks to silicon hydroxyls forming hydrogen bonds with epoxy molecules. Meanwhile, other molecules can be grafted onto APTES-APP via these silicon hydroxyls, if needed.Briefly, this work has developed a new strategy for amino silane as flame retardants. In conjunction with a low-cost and simple preparation method, APTES-APP has a promising prospect in the high-performance flame-retardant epoxy.
文摘The influence of silane coupling agent on the film forming of galvanized steel treated with cerium salt was studied by scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）, and the corrosion resistance of conversion films was analyzed by electro interstitial scanning （EIS）. The results show that silane coupling agent KH-570 has significant influence on the compactness and homogeneity of cerium conversion films, and the process of film forming is promoted by increasing the content of tervalent and tetravalent cerium oxide. The impedance value of the cerium conversion film, especially modified with KH-570, is greater than that of the base metal, which reveals that it is necessary to add silane coupling agent to the film-forming solution in order to improve the corrosion resistance of the conversion film.
基金Funded by the National Key Research and Development Project(No.2019YFC1908204)the Guiding Projects in Fujian Province(No.2023H0023)the Fuzhou Science and Technology Plan Project(No.2022-P-012)。
文摘Polyurethane/desulfurization ash(PU/DA)composites were synthesized using"one-pot method",with the incorporation of a silane coupling agent(KH550)as a"molecular bridge"to facilitate the integration of DA as hard segments into the PU molecular chain.The effects of DA content(φ)on the mechanical properties,thermal stability,and hydrophobicity of PU,both before and after the addition of KH550,were thoroughly examined.The results of microscopic mechanism analysis confirmed that KH550 chemically modified the surface of DA,facilitating its incorporation into the polyurethane molecular chain,thereby significantly enhancing the compatibility and dispersion of DA within the PU matrix.When the mass fraction of modified DA(MDA)reached 12%,the mechanical properties,thermal stability,and hydrophobicity of the composites were substantially improved,with the tensile strength reaching 14.9 MPa,and the contact angle measuring 100.6°.
基金the Foundation of National Key Technologies R&D Program-Shanghai World Exposition Special Project (Grant No.04DZ05803)the Special Project of Shanghai Nano-technology (Grant No.05nm05011)
文摘The reaction of ZnO nanoparticles grafted with KH570 silane coupling agent was carried out in water-alcohol mixed solvent. Several characterization methods were applied to analyzing the results of surface modification such as Soxhlet extraction, Fourier transform infrared spectroscopy （FT-IR）, transmission electron microscopy （TEM）, thermogravimetry （TG）, differential scanning calorimetry （DSC） and zeta potential （ζ）. The results of FT-IR and TG-DSC show that the desired reaction chains have been covalently bonded on the surface of ZnO nanoparticles. Zetasizer results reveal that the maximal absolute value of ζ of the modified ZnO particles in acetone medium was 67.0 mV, which was much higher than that of the unmodified ZnO particles. So the surface of nanosized ZnO changed from hydrophilicity to hydrophobicity and the dispersity of ZnO nanoparticles were improved simultaneously. Finally, the mechanism of graft modification was discussed.
基金The National Key R&D Program of China(No.2018YFC0406701)the National Natural Science Foundation of China(No.51778133,51739008).
文摘In order to reduce the agglomeration of nanographene and improve its dispersibility,six silane coupling agents were used to modify the surface of the nanographene particles.Visual inspection,Fourier-transform infrared spectroscopy,transmission electron microscopy,Raman spectroscopy,and X-ray diffraction were employed to evaluate the dispersion properties of the resulting graphene in an aqueous solution of silane coupling agents.Results show that all six types of silane coupling agents are efficient in promoting the dispersion of graphene in aqueous solutions,and no obvious sedimentation of the graphene dispersion solution is observed after a stationary storage period of 30 d.Taking 3-aminopropyltriethoxysilane(KH-550)as an example,after the graphene is dispersed in the KH-550 aqueous solution,the carboxyl group on the surface of the graphene reacts with the KH-550 amino group to form an amide bond,and KH-550 is successfully grafted onto the graphene surface.Polar functional groups ionize in water,creating an electrostatic repulsion effect,or hydrophilic functional groups form hydrogen bonds with water molecules,which is believed to improve the dispersion stability of graphene.The dispersed graphene is curled and contains many folds.Each fold has about three or four layers,with an interlayer spacing of about 0.65 nm.The dispersed graphene also has a complete lattice and a reduced number of defects.Nanographene disperses well in silane coupling agent aqueous solutions and can,therefore,be used to prepare cement-based composites.
基金Funded by the National Natural Science Foundation of China(No.51172173)
文摘We experimentally studied the fine lightweight aggregate with the particle size range of 3.15-4.75 mm used as functional bridge between FRP sheet and concrete substrate. However, problems would appear and how to deal with the interfacial transition zone（ITZ） and make it stronger is the key point for this concept. Considering that silane coupling agent（SCA） can provide a better bond on a silicon-containing material surface, it was introduced as a modifying material to further improve the bond quality of the ITZ between lightweight aggregate and cement paste. Results indicated that the water absorptivity of lightweight aggregate can be controlled by SCA solutions, and the pull-off bond strength, mechanical strength, and microhardness were increased, which was attributed to the optimized microstructure under the condition of an appropriate concentration of SCA.
文摘The surface modification of clay fines was carried out by using silanecoupling agent. By means of IR spectra etc, a study was made on the combined state ofcoupling agent and clay. A rubber--clay composite material with excellent performancehas been prepared.
文摘We used silane coupling agents to improve the bonding ability between wheat straw particles and UF resin, and investigated surface properties （wettability and surface roughness） and hardness of parti-cleboard made from UF-bonded wheat straw （Triticum aestivum L.） combined with poplar wood as affected by silane coupling agent content and straw/poplar wood particle ratios. We manufactured one-layered particleboard panels at four different ratios of straw to poplar wood par-ticles （0%, 15%, 30% and 45% wheat straw） and silane coupling agent content at three levels of 0, 5% and 10%. Roughness measurements, average roughness （Ra）, mean peak-to-valley height （Rz）, and root mean square roughness （Rq） were measured on unsanded samples by using a fine stylus tracing technique. We obtained contact angle measurements by using a goniometer connected to a digital camera and computer sys-tem. Boards containing greater amounts of poplar particles had superior hardness compared to control samples and had lower wettability. Panels made with higher amounts of silane had lower Rq values.
基金This work was support by the Special Funds for Major State Basic Research Projects of China(G1999064705).
文摘A novel silane coupling agent bearing sulfobetaine group, N,N-diethyl-N-（3-sulfopropyl）-aminopropyl- trimethoxysilane （DESATS）, was first designed, synthesized and characterized. Its solution property was studied by means of dynamic light scattering. DESATS was successfully bonded onto the surface of the glass and proved by ESCA. Platelet adhesion assay in vitro indicated that the nonthrombogenicity of glass slide modified with DESATS is greatly improved.
基金a grant from National Science Foundation of China (No. 39990570).
文摘A new kind of silane coupling agent, N- (β-aminoethyl ) - γ-aminopropyl triet hoxysilane, was used for DNA direct attachment on the surfaces of glass supports, then the immobilized DNA was hybridized with horseradish peroxidase (HRP)-labeled probe, and detected by using enhanced chemiluminescent method. In comparison with γ-aminopropyl triethoxysilane, the detection limits (S/N) of DNA were 10 pg and 75 pg respectively. Several experimental conditions of DNA attachING to glass supports were investigated, and the system of hybridization of nucleic acid on the surfaces of glass supports was developed.
基金Funded by the National Natural Science Foundation of China(Nos.21671086 and 21761013)the Ganzhou Key Research&Development Projects(Ganshikefa[2019]60)。
文摘To improve corrosion inhibition performance of copper foil with a novel two-step electrochemical modification processes,the surface of 35μm copper foils was coated with graphene oxide(GO)via electrochemical method at first step,then was further coated with 3-aminopropyltrimethoxysilane(APTS)at the second step.For the first step the copper foil acted as anode,and as cathode for the second one(we labeled it as E-GO).Optimum coating parameters for the preparation of E-GO coating are 5 V and 1 min with ratio of APTS/deionized water(DI)1.5/98.5(v/v).The physicochemical properties of modified coating were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM)and hydrophilicity test.Electrochemical behavior of different samples were also investigated.The experimental results indicate that anti-corrosion performance is significantly improved with two-step modified coating.And E-GO coating shows more positive corrosion potential and the highest corrosion resistance rate than others according to the Tafel curve.It is also found that surface hydrophobicity of E-GO coating is significantly improved.
文摘Aim To determine the effect of silane grafted polypropylene on the property of different filler/polypropylene composites. Methods Polypropylene (PP) composites filled with talc(Ta), baryta sulfate and calcium carbonate coupled with silane grafted polypropylene (PP-g-Si) were made, their mechanical properties and thermal properties were investigated, respectively. Results As compared with the non-coupled composites, the mechanical properties of PP/Ta/PP-g-Si composites were improved to some extent, though the values of tensile modulus and the strain at peak were decreased. But for PP/BaSO4 and PP/CaCO3 composites, the values of their mechanical properties varied slightly or even decreased with increasing PP-g-Si content within the experimental component. Meanwhile, PP-g-Si also affected the melting and crystallization behavior of PP in the composites. Conclusion PP-g-Si offers compatibilization in PP/Ta composites, but offers no-compatibilization in PP/BaSO4 and PP/CaCO3 composites within the extent of the present range of PP-g-Si, which shows that PP-g-Si can be used as the macromolecular coupling agent of PP and Ta composite.
文摘The surface treatment of silca fume with silane coupling agent prior w incorporation in a cement mortar resulted in composites exhibiting increuses in loss tangent by 5%-200% and storage modulus by 10%-20% , relative to the value obtained by using as-received silica fume. The scanning electron microscopy （SEM） images iindicate that there is a morphological difference in the cement paste with treated and as-received silica fume, The, X-ray diffraction （XRD）, infrared （IR） spectrum analyses and mercury intrusion porosimetry （ MIP ） have provided evidence to understand the reaction mechanism between treated silica .fume and the hydrate product of cement. This has led to the establishment of an initial microscopic model describing the damping behavior of cement matrix.
基金appreciate the financial support from the National Natural Science Foundation of China(No.20425621)the Major State Basic Research Program of China(No.2005CCA01000)the Basic Research Foundation of Shanghai Science and Technique Committee(No.05DJ14005).
文摘A novel surface treatment method using 3-aminopropyltriethoxysilane （AMPTES）, was developed to immobilize the fluorescein molecule on nano-HAP （nanometer hydroxyapatite） powders. By pretreating the nano-HAP powders surface with AMPTES, fluorescein, chosen on the basis of the chemical structure of the nano- HAP powders, could be bound to the nano-HAP powders surface. The chemical compositions of nano-HAP before and after being labeled were characterized by Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectron spectroscopy （XPS）. The morphology, phase composition, and the fluorescence characteristics of the nano-HAP powders with and without staining were also investigated. The FTIR and XPS results revealed that fluorescein had been successfully immobilized on the surface of AMPTES-bound nano-HAP powders via the acylamide bond formation between the -COOH of fluorescein and the -NH2 of AMPTES. The labeled nano-HAP powders possessed strong fluorescent intensity with a little deviation from the maximum emission wavelength of fluorescein. But the morphology and phase composition had no obvious alteration. Under fluorescence microscopy, the labeled nano-HAP powders, even after 24 h cell incubation, exhibited strong fluorescence.
基金Project supported by Beijing Youth Top-notch Team Support Project of China(2018000021223TD10)Hebei Province Fund for Transformation of Major Science and Technology Achievements of China(19041029Z)Hebei Province International Science and Technology Cooperation Base Construction Project of China(20591002D)。
文摘Based on the difference of the Y-terminal functional group of the silane coupling agent(Y-Si(X)_(3)),four different silane coupling agents were employed to pretreat the surface of the NdFeB powders.The effects of silane coupling agents on the flowability and compressibility of compounds for preparing bonded NdFeB magnets were studied.It is indicated that compounds pretreated by silane coupling agents have weaker friction and meshing force.The apparent density is increased by 0.3 g/cm^(3 )compared with the compound without silane coupling agent,and the radial crushing strength is significantly increased by about 3-4 times.In addition,the epoxy resin is more evenly distributed on the surface of the compounds treated by silane coupling agents observed by scanning electron microscopy,and some agglomerated particles are produced.Also,the compressibility of compounds with silane coupling agents is significantly improved due to the fact that hardening exponents are reduced.However,the addition of silane coupling agents has almost no effect on the magnetic properties of bonded magnets.The special energy was used to manifest the flowability of magnetic powder particles representing the macroscopic performance of the force between powder particles,providing a new direction for the study of the interface compatibility of two-phase or multiphase composite materials.
基金Funded by the Commission of Science Technology and Industry for National Defense(No.93013)
文摘Nano-SiO2/polypropylene composite was prepared by melt-blending process. The nano-SiO2 particles were organized by wet process surface treatment with silane coupling agent KH-570. The effect of mass fraction of nano-SiO2 particles and dosage of KH-570 on the toughening and strengthening of PP matrix were investigated based on the fractography of impact notch and the analysis of crystal structure by X-ray and dispersive structure of nano-SiO2 by TEM. Results show that the impact and flexural strength and modulus of the composite are improved obviously with low loading of nano-SiO2 （3 wt%-5 wt%）, and the izod impact strength of PP increases twice with 4 wt% nano-SiO2. The nano-SiO2 particles treated can disperse into the matrix resin, which has evident heterogeneous nucleation effects on the crystallization of PP. The optimal toughening and strengthening effects of PP matrix can be obtained when the content of nano-SiO2 and KH-570 are 4 wt% and 3 wt%, respectively.
基金Funded by the National Natural Science Foundation of China (Nos.20674063 and 20774074)the Specialized Research Fund for the Doctoral Program of Higher Education (20050736001)
文摘Palygorskite （PGS） and vinyl tris-（2-methoxyethoxy） silane （KH-172） modified palygorskite （OPGS） were used to prepare acrylonitrile-butadiene-styrene （ABS）/clay composites. Thermal stability of the composites was evaluated by using thermogravimetric analysis （TGA）. The morphology of the fractured surface and the degree of dispersion of the clay in the ABS matrix were observed by scanning electron microscopy （SEM）. X-ray diffraction （XRD） analysis results showed the variation of the crystal structure. Measurements of the tensile properties of the ABS/clay composites proved that the ABS/OPGS composited material represented the most excellent tensile property, because of good compatibility and dispersion of ABS with OPGS.
基金the University Synergy Innovation Program of Anhui Province(GXXT-2020-072).
文摘The chemical composition and high wear resistance of steel slag(SS)make it a potential alternative to traditional inorganic fillers.3-Aminopropyltriethoxysilane(KH550)modified steel slag(MSS)was successfully prepared,and its application in epoxy(EP)anti-corrosion coating was introduced.Due to the grafting of silane coupling agent functional groups onto the surface of SS,MSS exhibited improved solubility in xylene organic solvent and reduced agglomeration.When the MSS content was 15 wt.%,the contact angle of the MSS/EP composite coating was 101°,and the abrasion was only 0.07 g,compared with 56.2°and 0.13 g,respectively,for the pure EP coating.The corrosion resistance of coatings was investigated by performing the electrochemical test(impedance)after immersion in a 3.5 wt.%NaCl solution.The electrochemical test results showed that the impedance modulus of the 15 wt.%MSS/EP composite coating at low frequency(Z_(f)=0.01 Hz)was approximately 1.08×10^(7)Ωcm^(2),which was two orders of magnitude higher than that of the pure EP coating.
基金This work was supported by the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.18KJD430009)the Qing Lan Project of Jiangsu Province.
文摘Ag_(3)PO_(4)exhibits a high photocatalytic activity if exposed to visible light,however,it displays bottlenecks such as poor cycle-stability and mediocre ability to degrade methyl orange(MO)because of limited adsorption of MO molecules onto its surface.In this study,nano TiO_(2)prepared by a one-step method was combined with Ag_(3)PO_(4)to form a TiO_(2)@Ag_(3)PO_(4)heterojunction in order to improve this material both in terms of photocatalysis and photostability.After adding a KH-570 silane coupling agent,the photocatalytic performance of TiO_(2)@Ag_(3)PO_(4)could be improved even further,with the degradation rate of MO maintained at more than 90%after three cycles of visible in light.
