Γ-aminopropyl Trimethoxy Silane Research Articles

Enhancing Flame-Retardant Properties of Polyurethane Composites Using N-β-(Aminoethyl)-γ-aminopropyl Trimethoxysilane and Carbon Black Co-Modified Ammonium Polyphosphate

The search for a straightforward method to obtain efficient, affordable, and long-lasting flame retardants with both desirable flame-retardant and mechanical properties for polyurethane (PU) composites remains a significant challenge. In this study, the surface of ammonium polyphosphate (APP) was modified using N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane (KH792) via an ion-exchange reaction, and the modified APP was coated with nanoscale carbon black (CB) to obtain CBAPP. CBAPP demonstrated good compatibility within the PU matrix and notably increased the tensile strength of the PU composites. Furthermore, CBAPP significantly enhanced the flame-retardant properties of the PU composites. The CBAPP/PU composite with a CBAPP mass fraction of 20% achieved a limiting oxygen index of 41.5% and a UL-94 class of V-0. According to the results of this study, our modification approach can be applied to develop other high-performance flame-retardant polymer-based composites, representing a significant contribution to the field of fire safety materials.

Plasma electrochemical synthesis of silicon quantum dots

Environmentally friendly and fast synthesis of silicon quantum dots (SiQDs) is realized with the assistance of plasma. The precursors used are N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane (DAMO) and citric acid. When the excitation wavelength was 370 nm, the photoluminescence emission peak of the SiQDs appeared at 452.5 nm. The optimization of precursor concentration, reaction time and other parameters can effectively improve the quantum yield (QY) of SiQDs. The results show that the amidation and condensation of DAMO and citric acid plays an important role in the improvement of QY, as this means that more fluorescent molecules are produced and therefore QY is increased. This paper increases QY from 4.23% to 23.9%, providing a promising way to improve QY even more.

Carbon dot-based molecularly imprinted fluorescent nanopomegranate for selective detection of quinoline in coking wastewater

Quinoline, as a refractory and toxic organic pollutant in coking wastewater, causes great harm to the environment and human health even in trace amount. To realize the selective and sensitive detection of quinoline in coking wastewater, a novel molecularly imprinted fluorescent nanopomegranate with carbon dots (CDs) as seeds and fluorescence source (CD-MIP) was prepared, using quinoline as the template, and N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane (KH792) as the monomer. The preparation and detection conditions of CD-MIP were systematically optimized. The structure and detection performance of CD-MIP were investigated in detail. The resulting CD-MIP exhibits excellent photoluminescence performance, high detection sensitivity, good selectivity and reproducibility towards quinoline. Under the optimized conditions, the fluorescence intensity of CD-MIP shows a satisfying linearity with quinoline concentration in the range of 20–200 mg/L with a detection limit of 6.7 mg/L. Owing to the existence of imprinted cavities that highly match with quinoline, a high imprinting factor (3.46) for CD-MIP was obtained. In addition, CD-MIP represents a greater affinity towards quinoline than towards other analogues, as well as an outstanding anti-interference capability. For trace analysis in real coking wastewater, CD-MIP also gives satisfactory results. Therefore, CD-MIP shows promising application in the selective detection of trace quinoline in wastewater.

Environmentally benign and durable superhydrophobic coatings based on short fluorocarbon chain siloxane modified halloysite nanotubes for oil/water separation

Fluorinated siloxane (F-Si(OCH 3 ) 3 ) was synthesized from perfluoro (2-methyl-3-oxyhexyl) fluorine and N- (β-aminoethyl) -γ-aminopropyltrimethoxy silane, and then was used for hydrophobic modification of halloysite nanotubes (F-HNTs). A mixture of epoxy resin and F-HNTs was sprayed onto the surface of the stainless steel mesh. F-HNTs enhanced the surface roughness and reduced the surface energy, giving the mesh superhydrophobic/superlipophilic properties. The static water contact angle of coated mesh can reach 155.4 ± 0.3°. A series of oil and water mixtures can be separated, and the separation efficiency was higher than 97.8 ± 0.3%. After 50 cycles, the separation efficiency was still higher than 96.2 ± 0.5%. The coating mesh also had high separation efficiency for oil-water mixtures with different volume ratios and pH values. More importantly, the coated mesh still showed good stability in the harsh test conditions, such as strong acid, strong alkali, sand-paper wear and so on. Since the preparation of the coated mesh has the advantages of simplicity, scalability, and economy, it is expected to be applied on a large scale in the field of oil-water separation in the future. • Fluorosiloxane modified HNTs was used for fabricating superhydrophobic coatings. • Modified HNTs/epoxy was sprayed on the stainless steel mesh for oil-water separation. • This coated mesh has excellent separation efficiency and separation flux. • The coated mesh exhibited excellent stability under harsh external conditions.

Synthesis of a Novel Flame Retardant and Its Synergistic Effect With a Phosphapheanthrene Flame Retardant in Polypropylene/Polyethylene Vinyl Acetate Blends

ABSTRACTA novel flame retardant (NSiB) containing nitrogen, silicon and boron was synthesized through reacting of N-(β-aminoethyl)-γ-aminopropyl trimethoxy-silane (KH-792) and boric acid. The structure of NSiB was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy with energy dispersive spectrometry (SEM-EDS). The effects of NSiB on the flame retardancy and thermal behaviors of polypropylene (PP)/polyethylene vinyl acetate (EVA) blends were investigated by limiting oxygen index value (LOI), vertical burning tests (UL-94) and thermal gravimetric analysis tests (TGA). The results showed that the flame retardancy and thermal stability of PP/EVA blends were improved with the addition of NSiB. When 7.5 wt% DOPO (phosphaphenanthrene) and 0.5 wt% NSiB were incorporated, the LOI value of the PP/EVA blends was 26.9%, and the class V-0 of UL-94 test was passed, as compared to the LOI value of 22.4% and class V-2 of UL-94 test for 8.0 wt% DOPO only and 16.7% and fail, respectively, for the PP/EVA blends alone. The char structure observed by SEM indicated that the surface of the char for the PP/EVA/7.5 wt% DOPO/0.5 wt% NSiB blends had a denser and continuous char structure when compared with that of the PP/EVA blends and PP/EVA/8.0 wt% DOPO blends. These results indicated that there was a good synergistic effect for NSiB and DOPO.

The structure and properties of eucalyptus fiber/phenolic foam composites under N-β(aminoethyl)-γ-aminopropyl trimethoxy silane pretreatments

Abstract Eucalyptus fibers were modified with N-β(aminoethyl)-γ-aminopropyl trimethoxy silane to research the fiber surface’s changes and the influence of the treatment on the mechanical properties, flame resistance, thermal conductivity and microstructure of eucalyptus fiber composite phenolic foams (EFCPFs). The results showed that the partial of hemicelluloses, waxes, lignin and impurities from the fiber surface were dissolved and removed. Compared with untreated EFCPFs, the mechanical properties of treated EFCPFs were increased dramatically; The size of cells was smaller and the distribution was more uniform; The thermal conductivities were basically reduced; Especially the ratio of mass loss decreased obviously. However limited oxygen indexs (LOIs) reduced. And the mechanical properties and LOIs of EFCPFs were basically decreased with the increase of eucalyptus fibers. By comprehensive analysis, the results showed that the interfacial compatibility has been significantly improved between eucalyptus fibers and phenolic resin. And the suitable dosage of eucalyptus fibers was about 5%.

Improvement on Mechanical and Dynamic Properties of Palm Fiber/PLA Composites by Fiber Treatment

In this work, palm fiber reinforced polylactic acid composites were fabricated by hot-compress. The palm fibers were treated by γ-aminopropyl trimethoxysilane (APS) and coated with polylactic acid (PLA) in varied percentage (5%, 10% and 15%). The treatment reaction was analyzed by FTIR and the effect of fiber treatment on the flexural and dynamic mechanical properties of oil palm empty fruit bunch/polylactic acid (OPEFB/PL) composites were examined. The flexural properties of composites were increased with increasing of fiber coating and improved by introduction of APS. It was also observed that the APS treated fibers had improved the dynamic mechanical properties of the composites respectively.

Polyvinylidene fluoride/silane-treated hydroxyapatite mixed matrix membrane for enzyme capturing

The silane coupling agent, N-(β-aminoethyl)-γ-aminopropyltrimethoxy silane (KH792), was employed to modify the surfaces of nano-hydroxyapatite (HAP) particles. The mixed matrix membranes (MMMs) were prepared by embedding pure HAP and HAP modified with KH792 (KH792-HAP) inside polyvinylidene fluoride (PVDF) matrix respectively. The MMMs were further characterized concerning permeability and adsorption capacity. Langmuir adsorption isotherm provides better fit for HAP and KH792-HAP than Freundlich isotherm. KH792-HAP has better distribution in the polymeric matrix compared to HAP in the polymeric matrix. The MMMs showed purification of enzyme via static adsorption and dynamic adsorption, and showed the potential of using MMMs for enzyme capturing in enzyme purification techniques. The lysozyme (LZ) was used as a model enzyme. The properties and structures of MMMs prepared by immersion phase separation process were characterized by pure water flux, LZ adsorption and scanning electron microscopy (SEM).

Silane-incorporated epoxy coatings on aluminum alloy (AA2024). Part 1: Improved corrosion performance

This work consists of two parts. In the first part, adhesion property and corrosion performance of silane-incorporated epoxy coatings were systematically studied by pull-off test, salt spray test, electrochemical impedance spectroscopy and scanning electrochemical microscopy. The results showed that the silane agents, both the “active” γ-aminopropyltrimethoxy silane and the “non-active” bis-1,2-[triethoxysilyl]ethane not only reinforce the cross-linking of epoxy coatings but also strengthen the bonding at the coating/metal interface. These lead to better adhesion, less water uptake and swelling, and enhanced corrosion resistance of the coatings.

Silane-incorporated epoxy coatings on aluminum alloy (AA2024). Part 2: Mechanistic investigations

In the second part of this series work, the protection mechanism of epoxy–silane coatings was further investigated by combined use of sum frequency generation vibrational spectroscopy, FTIR mapping, XPS and AFM, from the microscopic point of view. Results showed that silane components, no matter γ-aminopropyltrimethoxy silane or bis-1,2-[triethoxysilyl] ethane, enhance the ordering of functional groups and exhibit healing effect and thus provide improved corrosion performance of superprimers. Phase separation was detected in epoxy coatings laced with immiscible bis-silane. Such phenomenon was gradually disappearing with prolonging the immersion, as a result of phase re-organization caused by the cross-linking reaction between silanes.

Catalytic activity of palladium nanoparticles immobilized on an amino-functionalized ceramic membrane support

Pd nanoparticles were immobilized on a tubular ceramic membrane support. The support surface was functionalized by N-(β-aminoethyl)-γ-aminopropyl trimethoxy silane (AAPTS), which contains two amino groups. The Pd-immobilized ceramic membrane support was characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma emission spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. Its catalytic properties were investigated by the liquid phase hydrogenation of p-nitrophenol to p-aminophenol. The Pd-immobilized ceramic membrane support was compared with the Pd nanoparticles immobilized on a similar support functionalized by γ-amino-propyltriethoxy silane (3-APTS), which contains one amino group. Higher catalytic activity and stability were observed for the AAPTS-functionalized support. AAPTS contains twice as many amino groups as 3-APTS, and consequently exhibited a stronger electron-donating effect toward Pd. The AAPTS-functionalized ceramic membrane support contained more immobilized Pd nanoparticles, which were bound more strongly. This led to a higher catalytic activity and stability.

Surface modification of apatite-wollastonite glass ceramic by synthetic coupling agent

In this study, lysine was introduced into the surface of apatite—wollastonite glass ceramic (AW-GC) to improve its cytocompatibility by two steps reaction procedure. Firstly, lysine connected to N-β-(aminoethyl)-γ-aminopropyl trimethoxy silane (A-1120) by covalent binding of amide group. Secondly, the lysine-functionalized A-1120 was deposited on the surface of AW-GC through a silanization reaction involving a covalent attachment. FTIR spectra indicated that lysine had been immobilized onto the surface of AW-GC successfully. Bioactivity of the surface modified AW-GC was investigated by simulated body fluid (SBF), and the in vitro cytocompatibility was evaluated by coculturing with human osteosarcoma cell MG63. The results showed that the process of hydroxyapatite layer formed on the modified material was similar to AW-GC while the mode of hydroxyapatite deposition was changed. The growth of MG63 cells showed that modifying the AW-GC surface with lysine enhances the cell adhesion and proliferation.

Study on Chromium-Free Pretreatment Solution of Color Coated Sheet

Based on the inorganic and organic composite pretreatment technology, a new chromium-free pretreatment solution consisting of Ce (NO3)3, N-β (aminoethyl)-γ-aminopropyl trimethoxysilane (KH792) and vinyltrimethoxysilane (KH171) was studied and used to treat galvanized sheet. Corrosion resistance of composite silane films on galvanized sheet surfaces was studied using CuSO4 pitting corrosion test and neutral salt spray test. Experimental results show that the corrosion resistance of composite silane film has improved significantly, compared to single silane film. The optimal condition of chromium-free pretreatment solution is that KH792/KH171 ratio is 4/1(v/v), Ce (NO3)3 content is 0.05%(w/w).

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.

Thermal Conductivity and Mechanical Properties of Wood Sawdust/Polycarbonate Composites

Wood sawdust was increasingly being used as reinforcement in commercial thermoplastics due to low cost, reusable raw materials. One of the problems of using wood sawdust is its interfacial adhesion with polymeric matrix. In this research, two types of silane coupling agents (N-(3-Trimethoxysilylpropyl) diethyllenetriamine and γ-aminopropyl trimethoxy silane) and sodium hydroxide were used for the modification of interfacial adhesion in wood sawdust/polycarbonate composites. The effects of chemical treatment and wood sawdust content (10, 20 and 30 % by wt) were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), thermal conductivity analysis. Youngs modulus of composites was in general higher than the neat PC except for the one with γ-aminopropyl trimethoxy silane treatment. Tensile modulus of composites was increased as the filler loading increased. Nevertheless, the addition of wood sawdust resulted in the tensile strength reduction of the composites. The SEM micrographs reveal that the aggregation of wood particles and weak interfacial bond between the treated wood sawdust and the polymeric matrix with increasing filler loading. Furthermore, the thermal conductivity was reduced significantly with the increment of wood sawdust contents.

Green synthesis of Au nanoparticles immobilized on halloysite nanotubes for surface-enhanced Raman scattering substrates

A facile and green route was introduced to synthesize Au nanoparticles immobilized on halloysite nanotubes (AuNPs/HNTs) used for surface-enhanced Raman scattering substrates. The naturally occurring HNTs were firstly functionalized with a large amount of -NH(2) groups by N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane (AEAPTES), which possesses one lone electron pair and will "anchor" Au ions to form a chelate complex. Then, with the addition of tea polyphenols (TP), the Au ions were reduced on the surface of the previously formed Au-NH(2) chelate complex to form AuNPs. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) observations indicate that a large amount of AuNPs were synthesized on HNTs. The AuNPs are irregularly spherical and densely dispersed on HNTs and the diameter of the nanoparticles varies from 20 to 40 nm. The interactions between AuNPs and -NH(2) groups were verified by X-ray photoelectron spectroscopy (XPS) and the results showed that the functional groups can "anchor" AuNPs through the chelating effect. The as-prepared AuNPs/HNTs nanomaterials with several nanometers gaps among nanoparticles were used as a unique surface-enhanced Raman scattering substrate, which possessed strong and distinctive Raman signals for R6G, indicating the remarkable enhancement effect of the AuNPs/HNTs.

Effect of Silane Coupling Agents on Rice Straw Fiber/Polymer Composites

The effect of coupling agents and electron beam (EB) irradiation dose on the mechanical properties of composites made from rice straw fibers and polymers have been studied. Samples were made by hot pressing of mix composition at 130°C. The pressed samples were subjected to electron beam irradiation dose ranged from 10 to 50 kGy. Increasing the electron beam irradiation dose increased the value of flexural strength, modulus of elasticity and impact strength. It was also observed that, the properties of composites containing γ-aminopropyltrimethoxy silane (A-1100) are lower than those of composites containing N-(2aminoethyl)-3-amino propyltrimethoxy silane (A-700) coupling agents. These are attributed to a hydrogen bonding formation between the amine or protonated amine and the hydroxyl groups of rice straw fibers. The presence of coupling agents in the composites during the EB irradiation process produce a more free radicals which are enough to form a chemical bonding between the rice straw fiber and polymer. The thickness swelling and water absorption values decrease with increasing the EB irradiation dose with presence of coupling agents in the composite.

Facilitated transport effect of Ag + ion exchanged halloysite nanotubes on the performance of polyetherimide mixed matrix membrane for gas separation

This study investigated the facilitated transport effect of Ag + ion exchanged halloysite nanotubes (HNTs) as filler on the gas separation performance of asymmetric mixed matrix membranes (MMMs). The polymer matrix employed in this study was commercial polyetherimide (PEI) Ultem 1000. The modified HNTs were prepared by treating HNTs with N-β-(aminoethyl)-γ-aminopropyltrimethoxy silane (AEAPTMS) and silver nitrate. FESEM, XRD, FTIR, TGA, DSC, EDX and pure gas permeation testing were used to characterise the modified HNTs and the fabricated MMMs. Three protocols were performed: (i) S-HNT MMM (no Ag + ion exchange treatment), (ii) S-Ag-HNT MMM (first Ag + ion exchanging and then silylation of HNTs), and (iii) Ag-S-HNT MMM (first silylation and then Ag + ion exchanging of HNTs). FTIR and TGA showed that silylation occurred successfully. From XRD we found out that, the Ag + ion exchanging did not affect the HNT crystalline structure. EDX revealed that, Ag + ion exchanging after silylation of HNTs resulted in much higher concentration of Ag + ions in the Ag-S-HNT product. This in turn showed that AEAPTMS could successfully enhance the HNTs cation exchange capacity (CEC), which resulted in higher concentration of Ag + ions in the modified HNTs. DSC disclosed depression in the glass transition temperature ( T g) of MMMs possessed Ag + ions. Three major factors were discussed: (i) facilitated transport affect of Ag + ions, (ii) Knudsen diffusion and (iii) T g depression. By increasing the fillers loading, all of the factors exhibited an additive influence on the permeability. The order of closeness of the resultant MMMs to the ideal morphology was as follows: Ag-S-HNT MMM > S-Ag-HNT MMM > S-HNT MMM. Ag-S-HNT MMM exhibited outstanding performance among the three protocols.

Mixed matrix membrane incorporated with large pore size halloysite nanotubes (HNT) as filler for gas separation: Experimental

This study investigated the gas separation and transport properties of asymmetric mixed matrix membranes (MMM) fabricated from polyetherimide (PEI); Ultem 1000 incorporated with raw and modified halloysite nanotubes (HNT) as filler. The modified HNTs; S-HNTs were prepared by treating HNTs with N-β-(aminoethyl)-γ-aminopropyltrimethoxy silane (AEAPTMS). FESEM, XRD, FTIR, TGA, DSC and pure gas permeation testing were used to characterise the S-HNTs and the fabricated MMMs. In the first part of the experiments, the effect of dope preparation factors such as: ultrasonic sonication period, filler wetting period and priming period were investigated. In the second part, the influence of silane concentration on the fabricated MMMs was studied. Results showed that, increasing the silane concentration, led to higher tendency in HNT agglomeration which resulted in poor separation properties but permeability enhancement. In the last part, the effect of S-HNTs loading was experienced. Our observations showed that the dispersion of nanoparticles decreased with an increase in the S-HNTs loading. Accordingly, 0.5% loading of silylated-HNT yielded the optimum MMMs in terms of permeability (27% increase) and selectivity (8% increase).

Adsorption behavior of γ-aminopropyl trimethoxysilane on copper foil.

The adsorption behavior of γ-aminopropyl trimethoxysilane (γ-APS) on copper foil is investigated by using X-ray photoelectron spectroscopy (XPS). Copper foil is immersed in a diluted aqueous solution of γ-APS and dried in air. It is found that γ-APS is adsorbed onto the surface almost without hydrolysis. Further, the depth profile by XPS analysis shows that γ-APS is not hydrolyzed even in the inside layer. In order to obtain hydrolyzed γ-APS on the copper foil surface, the foil is freeze-dried as immersed in a diluted aqueous solution of γ-APS. A hydrolyzed form of γ-APS is found on the top surface. Further, the presence of a powder is confirmed in the bottom of the flask at the end of the freeze-dry experiment. XPS analysis shows the powder is a linear polymer and produced from the silane coupling agent.