Γ-glycidoxypropyl Trimethoxysilane Research Articles

The influences of silane coupling agents on the heat and moisture resistance of basalt fibre‐reinforced composites

Basalt fibre composite materials have shown good application prospects in electrical equipment, but their reliability can be affected by damp-heat ageing. In this work, the interface, mechanical, and electrical properties of basalt fibre composites treated with three coupling agents via damp-heat ageing were compared. Molecular simulations were conducted to reveal the damp-heat ageing mechanism of the composites. The results show that γ-aminopropyl triethoxy silane (KH-550) and γ-glycidoxy propyl trimethoxy silane (KH-560) perform better as coupling agents as they form bonds with the matrix resin, compared with γ-methacryloxy propyl trimethoxy silane (KH-570). After the damp-heat ageing treatment, the hydrolysis of the defects of the amino groups in the interface of the KH-550-treated sample can weaken its mechanical properties and insulation properties greatly. The interface layer of the KH-560-treated sample is mostly composed of carbon–oxygen single bonds and methylene groups with its interface structure more stable, which endows the sample with better stability of its mechanical and insulating properties. Therefore, KH-560 is a more suitable coupling agent for processing basalt fibres to be used in electrical equipment.

Corrosion Resistance of Epoxy Coatings Modified by Bis-Silane Prepolymer on Aluminum Alloy

In this communication, a bis-silane prepolymer was used to modify epoxy resin, aiming to enhance the corrosion resistance of epoxy coatings on aluminum alloy substrates. The bis-silane prepolymer was prepared by tetraethoxysilane (TEOS) and γ-glycidoxypropyl trimethoxysilane (GPTMS). The corrosion behavior of silane-epoxy coatings was studied. Compared with silane monomer-modified epoxy coatings, bis-silane-modified epoxy coatings have lower coating capacitance (Cc), higher charge transfer resistances (Rdl), and lower double layer capacitance (Cdl) during long-time immersion. It indicates that bis-silane-modified epoxy coating has stronger waterproof permeability and substrate corrosion protection ability. In addition, due to the leaching of the silane component and cross-linking reaction between different silanes during the immersion process, the bis-silane-modified epoxy coatings exhibit much stronger “self-healing” ability.

Enhanced thermal conductivity for polybenzoxazine matrix composites by constructing a hybrid conductive network and modification of fillers

Polyhedral oligomeric silsesquioxanes (POSS) and γ-glycidoxy propyl trimethoxy silane (KH560) were applied to modify boron nitride (BN) and boron nitride whisker (BNw), and modified BN (m-BN) and modified BNw (m-BNw) were added as thermally conductive fillers to polybenzoxazine (PBz) matrix to synthesize m-BN/m-BNw/PBz composite by hot press. The research results indicate that the modification of BN and BNw and the synergistic effect between m-BN and m-BNw can significantly improve the thermal conductivity of PBz composite. The thermal conductivity of PBz composite with 25 wt % m-BN and 25 wt % m-BNw reached to 1.27 W/mK, which is 35% higher than PBz composite with 50 wt % m-BN (0.94 W/mK), 76% higher than PBz composite with 50 wt % BN (0.72 W/mK), and also display excellent electrical insulation performance. The corresponding dielectric constant (ε) and dielectric loss (tan δ) were 3.83 and 0.0078, respectively. Besides, the Theat-resistance index (THRI) of PBz composite with 25 wt % m-BN and 25 wt % m-BNw is 242.26 °C, and the thermal degradation temperature at 30% weight loss (T30) is 557.72 °C, are higher than PBz matrix (224.46 and 498.88 °C). And the tensile strength of PBz composites with 25 wt % m-BN and 25 wt % m-BNw is 47.71 MPa.

Corrosion Resistance of Bis-Silane-Modified Epoxy Coatings on an Al-Zn-Mg-Cu Alloy

A bis-silane prepolymer-modified epoxy coating was applied to an Al-Zn-Mg-Cu alloy to improve corrosion protection. The bis-silane prepolymer was synthesized from tetraethoxysilane and γ-glycidoxypropyl trimethoxysilane. To study the mechanism of protection failure by the silane–epoxy hybrid coating and to determine an appropriate coating for protection, various coatings with different silane prepolymer contents were developed. The corrosion behavior of the coatings was studied by electrochemical impedance spectroscopy in a 3.5 wt.% NaCl solution. In comparison with silane monomer-modified epoxy coatings, the bis-silane-modified epoxy coating had lower coating capacitance (Cc), higher charge transfer resistance (Rdl) and lower double-layer capacitance (Cdl) during long immersion times, indicating a higher resistance to water permeation and stronger protection against substrate corrosion. The lowest Cc and Cdl values were obtained by mixing epoxy and the bis-silane prepolymer at a ratio of 1:1.

Electrospun polyvinylidene fluoride/SiO2 nanofibrous membranes with enhanced electret property for efficient air filtration

Abstract There is a critical need for air filters with the abilities of removing particles effectively and allowing air to pass through easily to protect the public from increasingly serious air pollution; however, creating such a filter medium has proven to be extremely challenging. Herein, an air filtration material equipped with remarkable electrostatic effect is fabricated by electrospining polyvinylidene fluoride (PVDF) as the matrix polymer and silicon dioxide nanoparticles (SiO 2 NPs) modified by γ-glycidoxypropyl trimethoxysilane (GPS) as the charge enhancer. The premise of the design is that GPS modified SiO2 NPs can be uniformly distributed in PVDF fibers, generating abundant stable interfacial charges. Benefiting from the monodisperse state of GPS@SiO2 NPs, the resultant PVDF/GPS@SiO2 nanofibrous membrane exhibits remarkable electret effect with a surface potential of 12.4 kV and high filtration performance with a quality factor of 0.14, which has never been reported before. We envision that this work can provide new insight into the design and development of electret air filter media for various applications.

Interfacial adhesion: improving the mechanical properties of silicon nitride fibre - epoxy polymer composites

ABSTRACTIn this work silicon nitride (Si3N4) fibres, with diameters D50 = 300 nm, were successfully functionalised with a monolayer of γ-glycidoxypropyl trimethoxysilane (GPS) coupling agent. The surface modification was used as a method to enhance the dispersion and interfacial adhesion of the fibres in epoxy polymer composites. It is well known that strong interfacial adhesion between dispersed inorganic fibres and a polymer matrix improves the mechanical properties of the composite by providing an effective stress-transfer pathway between the matrix and the fibres. The functionalised Si3N4 fibres were dispersed into a commercial epoxy resin via tumble-mill mixing and ultra-sonication. Setting was initiated via addition of a poly-amine hardener and the composites were cured at room temperature for 24 hours. The fractured surfaces of the cured composite materials were analysed via SEM imaging and the mechanical properties of the composites were tested. The GPS-Si3N4 composites were shown to have improved bonding at the interface, which resulted in enhanced mechanical properties compared to the unfunctionalised Si3N4 composites, with improved tensile strengths and hardness values. This study shows the importance of achieving a strong interphase region between the surface of a fibre and the polymer matrix in fibre-reinforced polymer composites.

Effect of novel DOPO-g-coupling agent treated wood fibers on properties of composite phenolic foams

9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) graft γ-amino propyltriethoxy silane (APS), γ-glycidoxy propyltrimethoxy silane (GPS), and methacryloyl propyltrimethoxysilane (MPS) were synthesized and introduced on the surface of wood fiber. DOPO-g-APS (GPS and MPS) treated wood fibers (DAWF, DGWF, and DMWF) were used to prepare composite phenolic foams (DAWFCPF, DGWFCPF, and DMWFCPF). The chemical structures of DOPO-g-APS (GPS and MPS) were confirmed by Fourier transform infrared (FT-IR) spectra and nuclear magnetic resonance. The structures of DAWF, DGWF, and DMWF were confirmed by FT-IR. The diffraction peak positions were basically unchanged, but the crystallinity was slightly increased. Compared with WF, thermal stabilities were increased. The residue (800 °C) was slightly reduced. Compared with phenolic foam, the properties of DAWFCPF and DGWFCPF were better than others. Besides compression strength, the mechanical properties were increased dramatically, limited oxygen index was slightly enhanced, the cellular pore distribution was more regular, and the size of bubble cell was smaller and more uniform. By comprehensive analysis, the properties of DAWFCPF were best in all samples. The interfacial compatibility was significantly improved between DAWF and phenolic resin. These results confirmed that DOPO-g-APS is a suitable material for treating wood fibers and preparing composite phenolic foams.

Investigation on Physicomechanical, Thermal, and Morphological of Dipodal Silane-Modified Walnut Shell Powder-Filled Polyurethane Green Composites and Their Application for Removal of Heavy Metal Ions from Water

ABSTRACTDipodal silane-modified walnut shell powder polyurethane green composites have been prepared with different weight fractions of walnut shell powder viz., 0, 3, 6, and 10 wt% with surface-modified dipodal silane. The properties of dipodal silane-modified walnut shell powder-filled polyurethane green composites was investigated by tensile testing, Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The polyurethane/dipodal silane-modified walnut shell powder has been fabricated based on 3-aminopropyltriethoxysilane and γ-glycidoxypropyl trimethoxysilane. The green composites were analyzed by ultraviolet–visible in two different water solutions with Ni2+ and Pd2+ ions concentrations.

Synthesis, characteristics of hierarchical EU-1 zeolite for xylene isomerization probe reaction

Introduced a method of synthesizing hierarchical EU-1 zeolite with organosilanes as additive, and studied the influences of following different kinds of organosilanes on the synthesis of hierarchical EU-1 zeolite: γ-glycidoxy propyl trimethoxy silane (GPTMS), N-β-(aminoethyl)-γ-aminopropyl methyl dimethoxyl silane (APAEDMS), and N-(β-aminoethyl)-γ-aminopropyl dimethoxyl (ethyoxyl) silane (TMPED). The hierarchical EU-1 samples were characterized by XRD, SEM, N2 adsorption, FT-IR and NH3-TPD to analyze the crystallinity, morphology, surface area, pore size distribution and acidity. The results showed that hierarchical EU-1 zeolites were successfully synthesized; organosilanes have great influence on crystal morphology of EU-1 zeolites; the exterior surface area of hierarchical EU-1 zeolite, which synthesized with organosilanes (APAEDMS) adding into synthesis system, increased by 62.1% and mesopore volume increased by 129.1% compared with conventional EU-1 zeolites, thus can reduce the diffusional restriction markedly in catalytic reaction. The catalytic performance of hierarchical EU-1 zeolites were evaluated in m-xylene isomerization on fixed bed reactor. The catalytic data showed that the isomerization activity PX/X of the hierarchical EU-1 zeolites reached around 24.09% in theoretical thermodynamic equilibrium from 23.83%, and the selectivity of C8 aromatic hydrocarbon increased from 75.16% to 84.87%. The conversion of p-xylene increased from 16.30% to 18.41%.

Organic / Inorganic Nanosilica Support Role in the Recovery of Terephthalic Acid from Poly(Ethylene Terephthalate) Wastes

In this report the efficiency of organically modified nanosilica namely, γ-glycidoxy propyl trimethoxy silane / diethanol amine (GDS) was evaluated in the recovery of terephthalic acid from poly (ethylene terephthalate) wastes received from used soft-drink bottles. In this study, organically modified nanosilica used as the solid support, diethylene glycol (DEG) as the solvent and sodium hydroxide as the catalyst and the support performances was examined in detail and the results were compared with unsupported reaction. Results showed that (GDS) delivered good performance as the reagent and solid support in depolymerizing of poly (ethylene terephthalate) to the terephthalic acid. The highest terephthalic acid (86%) recovery yield was reached at NaOH (0.3 g), GDS (0.02 g) and PET: waste molar mass ratios (1:3), respectively. In addition, obtained data showed that in the presences of GDS (0.02 g) required reaction time for complete glycolysis decreases up 98% and by exceeding the GDS to 0.05 g, the consumption of the solvent decreases to 62.5% in comparison with unsupported reaction.

Enhancing the biological activity of chitosan and controlling the degradation by nanoscale interaction with bioglass.

A nonuniform degradation of physical mixture of organic-inorganic biomaterials increases their risk of failure. In this study a chemical bonding between chitosan and bioglass was used as an alternative product to address this issue. To prepare a homogenous composite, chitosan was functionalized with γ-glycidoxypropyl trimethoxysilane and chemically bonded with bioglass during sol-gel method. The gelation time of these hybrids samples was optimized by varying parameters such as composition of chitosan and temperature. It was shown that gelation time was reduced from 7 days for pure bioglass at 25°C to less than six minutes at 70°C for chitosan 40 vol % bioglass hybrid. Furthermore, the enzymatic degradation after 4 weeks was decreased from 80% mass loss for pure chitosan to 32% for chitosan 40 vol % bioglass hybrid. The results of in vitro study demonstrated that the presence of nanoscale interaction enhanced the bioactivity of chitosan. Additionally, hybrid scaffolds were fabricated with pore sizes in the range of 200-400 µm. These scaffolds were prepared by the addition of sodium bicarbonate during sol-gel method as a gas foaming agent and a neutralizer that resulted in decreasing the gelation time of hybrids to less than three minutes. The hybrids fabricated in this study possessed superior characteristics compared to chitosan, also physical mixture of chitosan-bioglass and are promising alternatives for bone tissue engineering applications.

Mechanical and Thermal Properties of Siloxane Reinforced Biphenyldiol Formaldehyde Resin Curing Epoxy Resin Composites

In order to modify the properties of the epoxy composites, an alkali catalyzed biphenyldiol formaldehyde resin (BPFR) was synthesized and used to cure epoxy resin (ER). γ-Glycidoxypropyl trimethoxysilane (KH-560) was used as a reinforcer of the composites. Laminates of the BPFR/ER fiberglass reinforced composites with different (KH-560) contents were prepared. The influence of the KH-560 content on the glass transition temperature (Tg) and thermal degradation properties of the composites was researched by dynamic mechanical analyzer (DMA) and thermogravimetric analysis (TG). The mechanical, electrical properties of the composites were determined. The results showed that the interfacial bonding strength between resin matrix and fiberglass can be efficiently improved with the presence of KH-560. When the ratio of BPFR and ER is 3 : 7, the content of KH-560 is 5 ~7 wt%, the impact resistance of the fiberglass reinforced composites is 61.35~78.59 kJ/m2, the tensile resistance is 150.37~162.54 MPa, which are all 30 % higher than that of no added; The dielectric constant ε and dielectric loss tanδ of the composites is between 0.50~0.68 and between 0.008~0.01, respectively.

Synthesis and characterization of whisker surface imprinted polymer and selective solid-phase extraction of trace Sr(II) from environment aqueous solution

A novel surface ion-imprinted polymer (S-IIP) has been synthesized by surface ion-imprinting concept in the presence of sodium trititanate whisker, Sr(II), chitosan and γ-glycidoxypropyl trimethoxysilane (KH-560) for selective solid-phase extraction of trace Sr(II) from environment aqueous solution. Characterizations of S-IIP were achieved by infrared spectra and surface area measurement. S-IIP was used in the sorption–desorption process; the effect of solution pH, sorbent amount, and flow rate on the extraction of Sr(II) ions from aqueous solutions was investigated. The adsorption kinetics and isotherm were also obtained in detail. The dynamical study showed it was well followed the pseudo-second-order kinetic equation in the adsorption process. Meanwhile, the equilibrium adsorption studies showed that it very good fit the Langmuir isotherm equation for the monolayer adsorption process, and the maximum adsorption capacity was 32.60 mg/g. Selectivity experiments showed that S-IIP had a higher selectivity than non-imprinted polymer. The thermodynamic parameters (positive values ΔG°, ΔH°, and ΔS°) confirmed the non-spontaneous, endothermic, and entropy gained nature within the temperature range evaluated. The precision relative standard deviation and detection limit of this method were 0.93% and 0.30 μg/L, respectively, and it was successfully applied to the determination of trace Sr(II) in different wastewater samples with satisfactory results using inductively coupled plasma atomic emission spectrometry.

Effect of Silane Coupling Agent on the Flexural Property of Glass Fiber Reinforced Composite Film

Transparent glass fiber reinforced composites films ware fabricated by UV light induced chemical crosslinking of composite materials consisting of glass fiber and UV curable resin in film state. In order to apply film to flexible device, excellent flexural property is required, then the delamination should not occurred between glass fiber and UV curable resin when film is bent. To minimize delamination and improve the interfacial adhesion at interface between glass fiber and UV curable resin, the γ-aminopropyl triethoxy silane and γ-glycid oxypropyl trimethoxy silane were applied for the surface treatment of glass fibers. Silanization of glass fiber surface was checked by scanning electron microscopy and the degree of delamination of composite film was confirmed through the bending test, ASTEM290-96a, used by haze meter.

Preparation and application of an emodin-bonded silica gel chromatographic column for high performance liquid chromatography

An emodin-bonded silica gel stationary phase (ESP) for high performance liquid chromatography has been synthesized by the intermediate method. The preparation process was as follows: γ-glycidoxypropyltrimethoxy silane (KH-560) firstly reacted with emodin ligand; then the intermediate was chemically immobilized to the surface of silica gel. Characterization of ESP was carried out with Fourier transform infrared spectroscopy (FTIR), elemental analysis and thermogravimetric analysis. Naphthalene was used as a probe to determine the column efficiency with methanol-water (60:40, v/v) as binary mobile phase at a flow rate of 0. 8 mL/min. In order to elucidate the related separation mechanism, ESP was used to separate a series of neutral, basic and acidic aromatic compounds, as well as a sample of wind medicated oil. The conventional C18 column and phenyl column were also tested under the same chromatographic conditions for comparison. The results showed that the emodin ligand was successfully bonded to the surface of spherical silica gel with a 0.23 mmol/g of bonded amount, and the theoretical plate number of ESP column was about 19,874 N/m. The coupling reagent chains and anthraquinone rings in ESP offered a structural basis for hydrophobic interaction. Meanwhile, the emodin ligands provided π-π or π-ρ charge transfer, hydrogen bonding, dipole-dipole action sites for different analytes. The synergistic reaction of various action sites endowed ESP column special and excellent chromatographic separation selectivity. And a baseline separation of polar compounds such as amines and phenols on ESP was easily achieved by using common and cheap methanol-water mobile phases without buffer salts. The experimental conditions were simple and convenient.

Mechanical, thermal and dielectric properties of aluminum nitride/epoxy resin composites

Aluminum nitride (AlN) microparticles treated by silane coupling reagent of γ-glycidoxy propyl trimethoxy silane (KH-560) are employed to fabricate AlN/epoxy (AlN/EP) composites. Initially, both the flexural and impact strength of the AlN/EP composites increased, but later decreased with excessive addition of AlN. The mechanical properties of the composites are optimal with 5 wt% AlN. The thermal decomposition temperature and the dielectric constant of the composites increased with the addition of AlN. The thermal conductivities of the AlN/EP composites improved with the increasing addition of AlN, and the thermal conductive coefficient is 0.98 W/mK with 70 wt%-treated AlN. For a fixed AlN loading, the surface treatment of AlN by KH-560 exhibits a positive effect on the thermal conductivities and mechanical properties of the composites.

Solid Phase Extraction of Trace Cobalt(II) from Aqueous Solutions through Physicochemical Adsorption by Surface Ion-Imprinted Polymer

A novel surface ion-imprinted polymer (S-IIP) has been synthesized by surface ion-imprinting concept in the presence of sodium trititanate whisker, Sr(II), chitosan and γ-Glycidoxypropyl trimethoxysilane (KH-560) for selective solid-phase extraction (SPE) of trace Co(II) from aqueous solutions. Characterizations of S-IIP were achieved by FT-IR spectra, SEM and surface area measurement. Results showed that the adsorption of cobalt(II) onto S-IIP follows pseudo-second order kinetics and could be fitted by the Langmuir isotherm with the maximum adsorption capacity Q being 8.27 mg×g-1 at 25°C. Thermodynamic parameters including DHº, DGº andDSº were calculated and it is indicated that Co(II) adsorption on S-IIP is exothermic, spontaneous and physical adsorption reaction. Moreover, according to the dimensionless separation factor RL (RL<1) it indicates that it’s a highly favourable adsorption. Finally, the detection limit (3s) of 5.6 ng·mL-1with the relative standard deviation (RSD) for 1.0 μg×mL-1 cobalt(II) of 1.86% (n=10) were obtained.

Structure and Corrosion Resistance of a Composite γ-Amino Propyl Triethoxy Silane and γ-Glycidoxy Propyl Trimethoxy Silane Conversion Coating on Galvanized Steel

In an aqueous solution of the mixtures of γ-amino propyl triethoxy silane and γ-glycidoxy propyl trimethoxy silane, a composite silane conversion coating was developed on galvanized steel. FESEM (field emission scanning electron microscope), XPS (X-ray photoelectron spectroscopy), ATR-FTIR (attenuated total reflection Flourier transform infrared spectroscopy) and SST (salt spray test) were used to characterize the obtained composite silane conversion coating and also the coating formation process was studied. The result showed that the surface of the composite silane conversion coating was complete, consecutive and compact. The coating could endure a neutral salt spray test for 72 h without corrosion. The result of salt spray test indicated that the composite silane conversion coating can provide a better corrosion inhibition than the coating which was composed of the single silane. Based on observation and analysis, it was proposed that the formation process of the silane coating on zinc should consist of three steps: the hydrolysis of the silane molecules, silane chemical adsorption and silane crosslinking condensation. The crosslinking reactions took place between γ-amino propyl triethoxy and γ-glycidoxy propyl trimethoxy silane during the forming process of the coating, and a high crosslinked density interpenetrating structure network was obtained, so the composite silane conversion coating could keep the corrosive substances from the zinc more effectively.

Enhanced Thermal Conductivity of Epoxy Composites with MWCNTs/AlN Hybrid Filler

To further improve the thermal conductivity of epoxy resin, the multi-walled carbon nanotube/aluminum nitride (MWCNTs/AlN) hybrid filler was employed to prepare thermal conductivity MWCNTs/AlN/epoxy composite by casting process, and the silane coupling reagent of γ-glycidoxy propyl trimethoxy silane(KH-560) was also used to functionalize the surface of MWCNTs and/or AlN. Results revealed that, the thermal conductivity of epoxy resin was improved remarkably with the addition of MWCNTs/AlN hybrid filler, a higher thermal conductivity of 1.04 W/mK could be achieved with 29 wt% MWCNTs/AlN hybrid filler (4 wt% MWCNTs +25 wt% AlN), about 5 times higher than that of native epoxy resin. And the epoxy composite with 29 wt% MWCNTs/AlN hybrid filler possessed better thermal conductivity and mechanical properties than those of single 5 wt% MWCNTs or 40 wt% AlN. The thermal decomposition temperature of MWCNTs/AlN/epoxy composite was increased with the addition of MWCNTs/AlN hybrid filler. For given filler loading, surface treatment of MWCNTs and/or AlN by KH-560 exhibited a positive effect on the thermal conductivity of epoxy composite.

Improving the shear strength by silane treatments of aluminum for direct joining of phenolic resin

Phenolic resin was directly joined to aluminum using three different silane coupling agents, AEAPS (N-(β-aminoethyl)-γ-aminopropyl trimethoxy silane), McPS (γ-mercaptopropyl trimethoxy silane), and GPS (γ-glycidoxypropyl trimethoxy silane). The impacts of surface treatment conditions on the joint strength and interfacial properties were investigated. The joint strength was raised about 1.6–2.6 times that of the untreated aluminum when joined to phenolic resin. The chemical bonds were formed by the phenolic resin and the amino groups in AEAPS, while entanglement between the phenolic resin and the methylene groups in McPS was obtained. The results of cyclic thermal loading indicated that the interfaces were deteriorated and joint strength was decreased using GPS as the silane coupling agent when the number of cycles was increased. The interface was enhanced and the shear strength of joints was not decreased using AEAPS as the silane coupling agent.