Aminosilane Coupling Agent Research Articles

Fabrication of magnetic amino-functionalized nanoparticles for S-arylation of heterocyclic thiols

The aminosilane coupling agent and polyethylene imine-600 were loaded onto magnetic nanoparticles to obtain magnetic nanoligands (MNLs) A, B, C and D.

Corrosion protection of electroplated nickel using silane coupling agent

Electroplated nickel was chemically modified using an aminosilane coupling agent (as an alternative to chromate) in order to improve its corrosion performance. Infrared spectroscopy revealed that the silane bonded to the metal satisfactorily. The corrosion behaviour of a nickel electroplated steel workpiece was investigated using potentiodynamic polarisation and electrochemical impedance spectroscopy to optimise the silane deposition conditions. These data confirm that the most effective conditions are dipping in the silane coupling agent solution for 30 s and then curing at 100°C for 40 min.

Silane Coupling Agent for Attaching Fusion-Bonded Epoxy to Steel

We describe the possibility of using γ-aminopropyltriethoxysilane (γ-APS) to increase the durability of epoxy powder coating/steel joints. The curing temperature of epoxy powder coatings is frequently above 200 °C, which is seen so far as a major limitation for the use of the heat-sensitive aminosilane coupling agent. Despite this limitation, we demonstrate that aminosilane is a competitive alternative to traditional chromate conversion to enhance the durability of epoxy powder coatings/steel joints. Fourier-transform reflection-absorption infrared spectroscopy (FT-RAIRS), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) were used to identify the silane deposition conditions that influence the adhesion of epoxy powder coatings on steel. We show that AFM analysis provides highly sensitive measurements of mechanical property development and, as such, the degree of condensation of the silane. The joint durability in water at 60 °C was lower when the pH of the γ-APS solution was controlled at 4.6 using formic acid, rather than that at natural pH (10.6). At the curing temperature of 220 °C, oxidation of the carbon adjacent to the amine headgroup of γ-APS gives amide species by a pseudofirst-order kinetics. However, a few amino functionalities remain to react with oxirane groups of epoxy resin and, thus, strengthen the epoxy/silane interphase. The formation of ammonium formate in the acidic silane inhibits the reaction between silane and epoxy, which consequently decreases the epoxy/silane interphase cohesion. We find that the nanoroughness of silane deposits increases with the cure temperature which is beneficial to the wet stability of the epoxy/steel joints, due to increased mechanical interlocking.

Hindered phenol grafted carbon nanotubes for enhanced thermal oxidative stability of polyethylene

A hindered phenolic antioxidant has been covalently grafted onto the surface of multi-walled carbon nanotubes (MWCNTs) to improve their dispersion state and antioxidant ability in the polymer matrix. An aminosilane coupling agent was chosen as the surface modifier of the MWCNTs to create chemical bonding between the phenolic antioxidants and the MWCNTs. Two contrasting routes, two-step functionalization and one-step functionalization of MWCNTs, were developed. The corresponding MWCNT/polyethylene composites were prepared by melt blending. Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, thermal gravimetric analysis, transmission electron microscopy, and Raman spectroscopy confirmed the successful functionalization of MWCNTs. Electron spin resonance spectra revealed that the free radical scavenging activity of MWCNTs was greatly increased after functionalization. The resultant MWCNTs exhibited improved dispersion and antioxidant efficiency in the polyethylene matrix. Compared with the two-step functionalized MWCNTs, the one-step functionalized MWCNTs were more efficient in preventing polyethylene from thermal oxidative degradation.

Introduction of Size-Controlled Nafion/ZrO2 Nanocomposite Electrolyte into Primary Pores for High Pt Utilization in PEFCs

Decreasing the size of an electrolyte used as a catalyst layer increased the platinum (Pt) utilization ratio by introducing the electrolyte into the primary pores, which are the spaces inside the agglomerated Pt-supported carbon black. An organic–inorganic hybrid material, a capping electrolyte, composed of autoclave-treated Nafion and surface-modified zirconium oxide with acetylacetone and aminosilane coupling agent, has a smaller Stokes diameter in solution than Nafion. Electrochemical measurements of a membrane electrode assembly (MEA) show that the Pt utilization ratio was improved when the capping electrolyte was used. Furthermore, a combination of the introduction of capping electrolyte into the primary pores and formation of the proton-transport pathway around the agglomerated particles improved the performance of the MEA in the low current density region, where the reaction area affects the performance, compared with the MEA made with a Nafion electrode.

Preparation and characterization of radiolabeled magnetic nanoparticles as an imaging agent

Magnetic nanoparticles were prepared by a reduction–precipitation method and coated with an amino silane coupling agent. Guanine (Gua) was conjugated to the magnetic nanoparticles (MNPs) using glutaraldehyde as a cross-linker. Common techniques (Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and vibrating electron microscopy) were used to assess the properties of the particles. Structural investigations showed that amino silane-coated MNPs had a particle size of about 40–60 nm in diameter with a spherical morphology. The guanine-conjugated MNPs were radiolabeled with 99mTc(I)-tricarbonyl core (99mTc(CO)3-MNP-Gua) with a labeling yield of 72 ± 4 %. Pure radiolabeled magnetic particles were obtained by washing them with saline solution, and the radiochemical purity of 99mTc(CO)3-MNP-Gua was 98 ± 2 % in the final solution. The biologic distribution of guanine MNPs was assessed in New Zealand rabbits using a gamma camera. In the in vivo experiment, a high level of radioactivity was observed in the lungs and liver soon after intravenous administration of 99mTc(CO)3-MNP-Gua.

Effect of Amino Silane Coupling Agent on the AC Electrical Breakdown Phenomena of Epoxy/Layered Silicate Nanocomposite in Needle-plate Electrodes

The effects of amino silane coupling agent on the AC electrical treeing and breakdown behaviors in an epoxy/layered silicate (1 wt%) were examined in needle-plate electrode geometry. A layered silicate was exfoliated in an epoxy base resin by using our AC electric field apparatus. To measure the tree initiation and propagation and the breakdown rate, an alternating current (AC) of 10 kV (60 Hz) was applied to the specimen in needle-plate electrode arrangement with a 30℃ insulating oil bath. In the epoxy/amino silane system, the tree initiation time was 11.5 times higher and the breakdown time was 17.9 times higher than those of the neat epoxy resin. The tree initiation time in the epoxy/layered silicate (1 wt%) system with the amino silane was 2.0 times higher, and the breakdown time was 1.5 times higher than those of the epoxy/layered silicate (1 wt%) system.

The interfacial modification of rice straw fiber reinforced poly(butylene succinate) composites: Effect of aminosilane with different alkoxy groups

AbstractThe effect of aminosilane on the properties of rice straw fiber (RSF) reinforced poly(butylene succinate) (PBS) composites was studied. RSF was pretreated with four different aminosilane coupling agents, 3‐aminopropyltriethoxysilane (APTES), 3‐aminopropyltrimethoxysilane (APTMES), 3‐(2‐aminoethylaminopropyl)triethoxysilane (AEAPTES), and 3‐(2‐aminoethylaminopropyl)‐trimethoxysilane (AEAPTMES). The results of Fourier transform infrared spectroscopy (FTIR) and ζ potential measurements confirmed that amino groups were introduced to the silane‐treated RSF (TRSF) for all four silane coupling agents. The results also indicated a higher degree of hydroxyl ion adsorption by the fiber surface, which was chemically grafted by silane hydroxyl, was obtained with ethoxy silane than with methoxy silane. This difference might be because the relative rates of hydrolysis and ensuing silanol self‐condensation of methoxy silane were too fast to reduce the number of silanol groups grafted on the fiber surface. The TRSF composite produced clearly enhanced tensile properties for the aminosilane coupling agents having ethoxy groups. The AEAPTES‐RSF‐PBS composite showed the highest tensile strength. It might be because of the higher amino content of AEAPTES than APTES; the amino groups on the surface of TRSF were confirmed by FT‐IR to react with the carbonyl groups of PBS to form a blue‐shifted hydrogen bond. The water absorption process of composites was found to follow the kinetics and mechanisms described by Fick's theory. The aminosilane treatment significantly reduced the moisture diffusion coefficient but did not change the mechanism of water adsorption. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Synthesis and Structure of Environmentally Friendly Hybrid Clay/Organosilane Nanocomposite Coatings

Environmentally friendly polysiloxane and clay/polysiloxane composite coatings were synthesized on aerospace-grade aluminum alloy AA2024-T3 substrates from mildly acidified aqueous solution. The polysiloxane coatings were synthesized by acid-catalyzed hydrolysis and condensation of organosilane coupling agents such as glycidoxypropyltrimethoxysilane (GPTMS) and tetramethoxysilane (TMOS) followed by solution drop-casting onto the substrate to form self assembled nanoparticles, coating. The epoxy polysiloxane coating formed by condensation reaction of hydrolyzed TMOS and GPTMS was subsequently cured with aminosilane coupling agent to form cross-linked polysiloxane coating. Clay/polysiloxane coating was formed by dispersing about 0.1–0.3wt% of clay in the hydrolyzed TMOS/GPTMS solution followed by solution casting and the resulting clay/polysiloxane composite coating was subsequently cured with aminosilane coupling agent. The structure and composition of organosilane coupling agents and hybrid polysiloxane coatings were determined by reflection–absorption infrared spectroscopy (RAIR) and X-ray diffraction spectrometry (XRD). The hydrolysis, condensation and curing reactions of TMOS and the organosilane coupling agents were studied by analyzing thin films cast on aluminum alloy substrate after a predetermined reaction time by using RAIR. The XRD results show that the resulting polysiloxanes are semi-crystalline polymers. Wide angle XRD analysis indicated that clay dispersed in clay/polysiloxane composite coating is either highly intercalated or partially exfoliated. This inference was drawn from the disappearance of d001 diffraction peak for clay from the XRD spectrum of clay/polysiloxane coatings cured at 100 °C for 2.5 h.

Adsorption of 4-nitrophenol on palm oil fuel ash activated by amino silane coupling agent

Abstract Adsorption of 4-nitrophenol on palm oil fuel ash activated by amino silane coupling agent was investigated. Experiments were carried out at 30°C as function of contact time, initial concentration (2500–4500 mgl−1) and pH (1–7.4). The equilibrium adsorption data of 4-nitrophenol on activated palm ash were analyzed by Langmuir Freundlich and Temkin models. The results indicated that the Langmuir model provides the best correlation of the experimental data. The maximum adsorption capacity of the activated palm oil fuel ash was determined with the Langmuir equation and found to be 1000 mg g−1 adsorbent at 30oC. Adsorption kinetics data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion equations. It was shown that pseudo-second-order kinetic equation could best describe the adsorption kinetics. The results obtained in this work indicate that activated palm oil fuel ash is suitable as adsorbent material for adsorption of 4-nitrophenol from aqueous solutions.

Adsorption of 4-nitrophenol on palm oil fuel ash activated by amino silane coupling agent

Adsorption of 4-nitrophenol on palm oil fuel ash activated by amino silane coupling agent

Preparation and Adsorption Activities of Attapulgite Modified by Amino-silane Coupling Agent

Attapulgite(ATT) modified by the hydrochloric acid(HATT) was grafted by amino-silane coupling agent KH-792(N-beta-(aminoethyl)-gamma-aminopropyl-trimethoxysilane).Thermal behavior and the structure of the grafted HATT(KHATT) were characterized by FTIR,TGA,DSC,XRD and BET.The results showed that the KH-792 molecules were successfully grafted onto the HATT surface.The adsorption of Cr(Ⅵ) onto KHATT in stimulative water was also investigated.The results showed that removal rate of Cr(Ⅵ) in water was relatively high(85.15%) when the loading of KHATT is 3 g/L,pH of the water is 5.5 and the adsorption time of the KHATT is 40 min.The adsorption capacity of KHATT after four times regeneration retained at least 90% of the initial one,showing a high application value.In addition,an adsorption mechanism of KHATT for Cr(Ⅵ) was proposed.

Preparation of phenothiazine bonded silica gel as sorbents of solid phase extraction and their application for determination of nitrobenzene compounds in environmental water by gas chromatography–mass spectrometry

In this paper, two phenothiazine bonded silica (PTZ-Si) sorbents were prepared and used as sorbents of solid-phase extraction (SPE) for the determination of nitrobenzene compounds in environmental water samples by gas chromatography-mass spectrometry (GC-MS). Different synthesis routes were proposed to obtain high bonded amount of PTZ on the surface of silica gel. PTZ molecule was derived to its amino or acyl chloride derivatives for reacting with isocyanate or amino silane coupling agent, which was further reacted with the surface silanol groups of silica gel to obtain the PTZ-Si sorbents. The resultant PTZ-Si sorbents were characterized by nitrogen sorption porosimetry (NSP), Fourier transform infrared spectroscopy (FT-IR) and elemental analysis (EA) to assure the successful bonding of PTZ on the surface of silica gel. Then the PTZ-Si sorbents were served as SPE sorbents for the enrichment of nitrobenzene compounds. Several parameters affecting the extraction performance were investigated. Under the optimized conditions, the proposed method was applied to the analysis of six nitrobenzene compounds in environmental water samples. Good linearities were obtained for all nitrobenzene compounds with R(2) larger than 0.9958. The limits of detection were found to be in the range of 0.06-0.3 ng/mL. The method recoveries of nitrobenzene compounds spiked in water samples were from 71.4% to 124.3%, with relative standard deviations (RSDs) less than 10.1%.

Thermal and electrical properties of nitrile‐containing polyimide/BaTiO3 composite films

AbstractPolyimide composite films were prepared by mixing the BaTiO3 particles into poly(amic acid) solution followed by film casting and thermal imidization under controlled temperature conditions. The poly(amic acid) was synthesized by solution polycondensation reaction of 4,4′‐oxydiphthalic anhydride with 2,6‐bis(4‐aminophenoxy)benzonitrile, using N‐methyl‐2‐pyrrolidone as solvent. The surface of BaTiO3 particles was modified by treating with an aminosilane coupling agent, 3‐aminopropyltriethoxysilane. Fourier transform infrared spectroscopy, X‐ray diffraction and scanning electron microscopy were used to characterize the structure and properties of the composites. The influence of BaTiO3 content on the composite film properties was evidenced. The films exhibited good thermal stability having the initial decomposition temperature above 520°C. They had stable dielectric properties over large intervals of temperature and frequency. The dielectric constant and the dielectric loss increased with the increase of BaTiO3 content. The dynamic mechanical analysis and dielectric spectroscopy revealed subglass transitions γ and β. At higher temperature an α‐relaxation that corresponds to the glass transition and a conductivity process were evidenced. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers

Interface Reaction and Molecule Recognition Among Wood Flour, Amino Silane Coupling Agent and POE-g-MAH Compatibilizer

The interface reaction and molecule recognition among wood flour, amino silane coupling agent and maleic anhydride grafted polyolefin compatibilizer were studied by fourier transform infrared analyzer (FTIR), scanning electron microscope with an energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectra (XPS). According to molecule recognition principles, γ-APS in the wood flour surface was identified by SEM-EDS. A new state of N1 s at 401.33 eV appears in XPS as γ-APS and maleic anhydride grafted polyolefin compatibilizer are introduced simultaneously, which shows the occurrence of reaction between γ-APS and maleic anhydride-grafted polyolefin compatibilizer, and amino is formed.

Preparation and characterization of near-infrared region absorption enhancer carbon nanotubes hybridmaterials

This paper describes a simple strategy for covalently attaching silica-coated gold nanorods (sGNRs) onto the surface of multi-walled carbon nanotubes (MWNT) to fabricate hybrid nanostructures. The crosslinked reaction occurs through interaction of carboxyl groups on the MWNT with the amino silane coupling agent modified sGNRs. TEM, FT-IR spectroscopy, UV-vis spectroscopy, and Zeta potential analysis have been used to study the formation of MWNT/sGNRs nanostructure. Furthermore, MWNT/sGNRs hybrid material shows an excellent solubility in aqueous solution and an enhanced absorption in the near-infrared region. It should open up new possibilities in nanomedicine as multimodal photoacoustic and photothermal high-contrat molecular agent.

Influence of coupling agents on material behaviour of glass flake reinforced polypropylene

This paper presents a study evaluating the effects of aminosilane and titanate coupling agents on the material properties of glass flake reinforced polypropylene and compares the results with pure polypropylene and untreated glass flake reinforced polypropylene. Tensile and flexural properties, impact resistance and residual stresses are strongly dependent on the type and level of coupling agent employed, whereas changes in melt-crystallisation and crystalline content of the polypropylene in the composite materials was minimal. Glass flakes modified with aminosilane gave higher stiffness and strength than the titanate treatment. Thermal expansion hysteresis provided an indication of the relative levels of residual stresses in the polymeric materials, which was verified using the layer removal method for determining residual stress distributions. Ultrasonic velocity measurements conducted on the composite materials before and after exposure to sub-zero temperatures proved useful in assessing the effectiveness of the various surface treatments in promoting interfacial adhesion.

1107 シランカップリング剤によりAPS改質されたa-C:H膜の細胞親和性評価(OS13-(6)オーガナイズドセッション《生体医工学及びバイオマテリアル》)

Hydrogenated amorphous carbon (a-C:H) film coatings have been collected much attention for biomedical application. a-C:H film has excellent properties such as biocompatibility, anticorrosion and low friction. Recently, it is reported that biocompatibility of a-C:H film can be controlled by surface condition. On the other hand, surface modification with amino-silane coupling agent is useful for improvement of biocompatibility on biomaterials. In order to assess the availability of surface modification with amino-silane coupling agent, the cytocompatibility of the a-C:H film with and without surface modification was discussed. In this experiment, after the a-C:H film deposition, the a-C:H surface was modified by amino-silane coupling agent(APS). The cytocompatibility of a-C:H film with and without APS modification has been investigated under cell culture by in-vitro studies .As results, surface conditions of the a-C:H film with and without APS modification were dramatically improved. The cytocompatibility is obviously improved because the number of cells is increased on the surface with our proposal modification technique and APS treatment.

Preparation of magnetic iron/mesoporous silica composite spheres and their use in protein immobilization

The iron/silica magnetic composite spheres were prepared by electrochemical method and reduced in hydrogen atmosphere at different temperatures. The morphology and structure of the composite were characterized by SEM, TEM and XRD. The iron/silica microspheres exhibit essential ferromagnetic behavior characterized by magnetometry. After being coated with silica in sodium silicate solution by acidifying technology, the surface of these magnetic composite spheres is with amino-silane coupling agent for their attachment to affinity ligands. Bovine serum albumin (BSA) was covalently immobilized onto the amino-silane modified magnetic silica supports by the glutaraldehyde method. The influence of pH, ionic strength as well as the initial protein concentration on BSA immobilization was studied. The results show that such amino-silane modified magnetic composite spheres are the effective supports for bioseparation and the maximum BSA immobilization capacity (up to 87.4 mg/g) is obtained in 0.1 mol/L phosphate buffer at pH 5.0.

Thermal and electrical behavior of polyimide/silica hybrid thin films

AbstractSilica‐containing polyimide films were prepared by sol‐gel technique using a poly(amic acid) and tetraethoxysilane. The poly(amic acid) was synthesized by solution polycondensation reaction of 4,4′‐oxydiphthalic anhydride with 2,6‐bis(3‐aminophenoxy)benzene and an aminosilane coupling agent, 3‐aminopropyltriethoxysilane. The properties of these films, such as water vapors sorption capacity, dynamic contact angles and contact angle hysteresis, thermal, and electrical behavior have been evaluated with respect to their structure. The polymer films exhibited good thermal stability having the initial decomposition temperature above 450°C, glass transition temperature in the range of 223−228°C, and low‐dielectric constant in the range of 2.64−3.16. Two subglass transitions, γ and β, were evidenced by dynamic mechanical analysis and dielectric spectroscopy. The surface morphology and the roughness were investigated by atomic force microscopy and scanning electron microscopy. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers