Propyl Triethoxysilane Research Articles

Supported Gold Nanoparticles for Alcohols Oxidation in Continuous-Flow Heterogeneous Systems

Gold nanoparticles (AuNPs) were anchored on alkynyl carbamate-functionalized support materials having the suitable features for application as catalysts in continuous-flow packed bed reactors. The functionalization step was carried out by grafting with the difunctional organosilane [3-(2-propynylcarbamate)propyl]triethoxysilane (PPTEOS) three commercial micrometer-sized oxide supports, i.e. silica, alumina, and titania. The alkynyl-carbamate moieties were capable of straightforwardly reducing the gold precursor HAuCl4 yielding the supported AuNPs systems Au/SiO2@Yne, Au/Al2O3@Yne, and Au/TiO2@Yne. A comparison among the three materials revealed that silica allowed the highest organic functionalization (12 wt %) as well as the highest gold loading (3.7 wt %). Moreover, a TEM investigation showed only for Au/SiO2@Yne the presence of homogeneously distributed spherically shaped AuNPs (average diameter 15 nm). Au/SiO2@Yne is an efficient catalyst, both in batch and flow conditions, in the oxidation of a large...

Effect of Coupling Agent on Mechanical Properties of Palm Petiole Nanofiber Reinforced Composite

Composites have replaced conventional materials due to their advantages such as low cost, low density, high strength, etc. recently the research has been focused on natural fibers as a suitable replacement for synthetic fibers for reinforcement in composites. Hence, in this work, natural fiber is extracted from palm petiole and this fiber is investigated for reinforcement in epoxy polymer. The fiber is subjected to different chemical treatments for enhancing the surface wetting and Nano cellulose will also be extracted from the fiber. The composite will be fabricated by using handlay-up method by using 1%, 2%, 3% volume fraction of cellulose nanofiber in the epoxy resin. It is observed that the increase of the nanofiber in 3% volume fraction gives the good tensile, flexural and impact strength. So they obtained chemically treated cellulose nanofiber was treated with the amino propyl triethoxysilane and 3% of the silanesilane treated nano-fiber fabricated. Then the mechanical testings of this is compared with the 3% of chemically treated nano-fiber composite. The silane treated nanofiber gives the best results.

Phosphoryl functionalized mesoporous silica for uranium adsorption

Phosphoryl functionalized mesoporous silica (TBP-SBA-15) was synthesized by modified mesoporous silica with γ-amino propyl triethoxy silane and tributyl phosphate. The obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray diffraction (SAXRD), thermo-gravimetric/differential thermalanalyzer (TG/DTA), N2 adsorption–desorption (BET) and Fourier transform infrared spectroscopy (FT-IR) techniques. Results showed that TBP-SBA-15 had large surface areas with ordered channel structure. Moreover, the effects of adsorption time, sorbent dose, solution pH, initial uranium concentration and temperature on the uranium adsorption behaviors were investigated. TBP-SBA-15 showed a high uranium adsorption capacity in a broad range of pH values. The U(VI) adsorption rate of TBP-SBA-15 was fast and nearly achieved completion in 10min with the sorbent dose of 1g/L. The U(VI) adsorption of TBP-SBA-15 followed the pseudo-second-order kinetic model and Freundlich isotherm model, indicating that the process was belonged to chemical adsorption. Furthermore, the thermodynamic parameters (ΔG0, ΔH0 and ΔS0) confirmed that the adsorption process was endothermic and spontaneous.

Efficiency of surface modified Ti coated with copper nanoparticles to control marine bacterial adhesion under laboratory simulated conditions

Titanium (Ti) used as condenser material in nuclear power plants encounter severe biofouling in marine environment which in turn affects the efficiency of the metal. To reduce the biofouling by marine microorganisms, surface modification of the Ti was carried out by anodization process to obtain nanotubes (TiO2-NTs). The electrolyte solution containing 1% of ammonium fluoride resulted in uniform growth of TiO2-NTs. TiO2-NTs were further coated with chemically synthesized copper nanoparticles (NT-CuNP) using 3-amino propyl triethoxy silane as a coupling agent. NT-CuNP was characterized by field-emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy and X-ray diffraction. The stability of the coating was determined by the amount of Cu+ ions released into the surrounding using AAS. The microbial adhesion on the surface of Ti, TiO2-NTs and NT-CuNP coupons were evaluated by sea water exposure studies using total viable count method and also characterized by FE-SEM for any morphological changes. The NT-CuNP coupons show a 60% reduction in microbial adhesion when compared to control Ti coupons.

Adsorption efficiency, thermodynamics and kinetics of Schiff base-modified nanoparticles for removal of heavy metals

Nanosilica particles modified by Schiff base ligands 3-methoxy salicylaldimine propyl triethoxysilane (MNS1), 5-bromo salicylaldimine propyl triethoxysilane (MNS2) and 3-hydroxy salicylaldimine propyl triethoxysilane (MNS3) were prepared, and their potential for separation of copper, lead, zinc, cadmium, cobalt and nickel ions from aqueous solutions was examined. The effect of parameters influencing adsorption efficiency including aqueous-phase pH, amount of adsorbent, stirring time and initial concentration of the metal ions was assessed and discussed. Although MNS1 and MNS3 removed lead ions efficiently, all adsorbents showed strong selectivity toward copper ions. It was shown that, under some circumstances, MNS3 decreased the amount of other ions, particularly cobalt, in the aqueous phase. The adsorbents were also applied for removal of copper and lead ions from real samples. Possible quantitative desorption of the metal ions loaded onto the adsorbents suggests their multiple uses in adsorption–desorption process. Investigation of temperature dependency of the process led to determination of the ΔH°, ΔS° and ΔG° values. This investigation indicates that the adsorption of copper ions onto the all studied adsorbents and lead ions onto MNS1 and MNS3 is endothermic. The Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms were tested to describe the equilibrium data. Pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion equations were applied to study the kinetics of copper and lead adsorption onto the modified nanoparticles. This investigation indicates that the process for all adsorbents follows pseudo-second-order kinetics and suggests a chemisorption mechanism for the adsorption processes by the studied adsorbents.

Preparation and Characterization of Water Absorbing and Anti-Fogging Coatings

Anti-fogging functional coatings have a broad application prospective in the fields of construction and transportation vehicles. In this study, superior water absorbing and anti-fogging coatings were prepared by a cure reaction using epoxy resins as water absorbent resins, hydroxyethyl ethylenediamine as a curing agent, γ-ammonia propyl triethoxy silane as a coupling agent, organic silicon sol as filler. The impact of additional polyethylene glycol (PEG) on the properties of water absorbing and antifogging coating has also been studied. The anti-fogging experiments were conducted in a 40 °C water steam bath, and the result shows that the sample with additional 4.0 % PEG has an anti-fogging time of 315 seconds (s), which is better than that without PEG (the anti-fogging time being 240s). Infrared spectroscopy and scanning electron microscope structure characterization indicate that the sample with additional PEG has an obvious three-dimensional network structure with hydroxyl groups, which leads to a great saturated water quantity and a superior anti-fogging performance.

Thermoresponsive Wrinkles on Hydrogels for Soft Actuators

Thermoresponsive Wrinkles on Hydrogels for Soft Actuators

Mechanical interfacial adhesion of carbon fibers-reinforced polarized-polypropylene matrix composites: effects of silane coupling agents

Thermoplastic composites are used in a variety of applications such as mass transit, auto-motive parts, and military structures [1-6]. Their appeal compared to conventional materials such as aluminum, steel, and thermoset composites for these applications lies in their high specific strength, corrosion resistance, superior impact resistance, high toughness, and ease of recycling [1-7].In recent years, carbon fibers (CF) have been widely used as reinforcing materials in high performance composites. CF present several advantages, including high modulus and strength, good stiffness, and creep resistance [8-10]. Despite these advantages, the CF/ther-moplastic composites have unsatisfactory mechanical properties because CF have poor in-terfacial adhesion with most thermoplastic polymers due to their non-polar surface.The interfacial adhesion between reinforcing fibers and polymer matrices in composites is the controlling factor in obtaining optimum mechanical properties of composites [11-13]. To achieve good interfacial adhesion between CF and thermoplastic matrices, it is necessary to increase the surface polarity. In this light, increasing the surface polarity for van der Waals forces and hydrogen bonding can improve the interfacial adhesion. In efforts to increase the surface polarity of CF, various surface treatment techniques have been applied, including plasma treatment, anodic oxidation, metal plating, and cou-pling treatment [14,15]. Among the various treatments, coupling treatment is known to be a very effective method for improving the interfacial adhesion between the fibers and the thermoplastic matrices [16].The role of coupling agents in improving the interfacial adhesion between polymers and inorganic surfaces has been widely documented [17,18]. However, the effects of different coupling agents on interfacial adhesion between CF and polar-modified thermoplastic matri-ces have yet to be explicitly identified. Therefore, the first objective of this study is to evaluate the influence of sizing treatments by silane-based coupling agents on the interfacial adhesion properties between the fibers and the thermoplastic matrix. Another objective is to investigate the effects of the presence of surface functional groups containing silane-oxygen groups on the mechanical properties of carbon fiber-reinforced maleic anhydride-grafted polypropylene.The CF used in this work were polyacrylonitrile based high strength fibers, T-700SC-13000 (12K unidirectional fabric; Toray, Tokyo, Japan). The average diameter of these CF was around 7 μm. A highly polarized polypropylene sheet prepared by maleic anhydride grafting (Homan Petrochemical Co, Seoul, Korea) was used as a matrix. The reagents used for the coupling treatments were vinyltriethoxy silane (VTES), 3-ami-no propyl triethoxy silane (APS), and 3-methacryloxy propyl trimethoxy silane (MPTS; Aldrich, St. Louis, MO, USA), denoted as VTES, APS, and MPTS, respectively. The acid and silane treatments of the CF were carried out by the following procedure. For the acid

The preparation of high-quality water-soluble silicon quantum dots and their application in the detection of formaldehyde

This paper reports the synthesis of water-soluble fluorescence silicon quantum dots (Si QDs) through a hydrothermal route with urea propyl triethoxysilane (UPTES) as the source of silicon and sodium citrate as the deoxidizer.

Synthesis, thermal and mechanical behavior of a silicon/phosphorus containing epoxy resin

ABSTRACTA liquid silicon/phosphorus containing flame retardant (DOPO–TVS) was synthesized with 9,10‐dihydro‐9‐oxa‐10‐phosphapheanthrene‐10‐oxid (DOPO) and triethoxyvinylsilane (TVS). Meanwhile, a modified epoxy resin (IPTS–EP) was prepared by grafting isocyanate propyl triethoxysilane (IPTS) to the side chain of bisphenol A epoxy resin (EP) through radical polymerization. Finally, the flame retardant (DOPO–TVS) was incorporated into the modified epoxy resin (IPTS–EP) through sol–gel reaction between the ethyoxyl of the two intermediates to obtain the silicon/phosphorus containing epoxy resin. The molecular structures of DOPO–TVS, IPTS–EP and the final modified epoxy resin were confirmed by FTIR spectra and 1H‐NMR, 31P‐NMR. Thermogravimetric analysis (TGA), differential scanning calorimetry, and limiting oxygen index were conducted to explore the thermal properties and flame retardancy of the synthesized epoxy resin. The thermal behavior and flame retardancy were improved. After heating to 600°C in a tube furnace, the char residue of the modified resin containing 10 wt % DOPO–TVS displayed more stable feature compared to that of pure EP, which was observed both by visual inspection and scanning electron microscope (SEM). Moreover, the mechanical performance testing results exhibited the modified epoxy resins possessed elevated tensile properties and fracture toughness which is supported by SEM observation of the tensile fracture section. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42788.

Nanocrystalline Titanosilicate–Acetylcholinesterase Electrochemical Biosensor for the Ultra‐Trace Detection of Toxic Organophosphate Pesticides

AbstractIn this work, nanocrystalline titanosilicate and ZSM‐5 were synthesized in the presence of propyltriethoxy silane as an additive. Electrochemical biosensors based on nanocrystalline zeolites were fabricated through the covalent immobilization of the enzyme acetylcholinesterase for the ultra‐trace detection of toxic organophosphate pesticides such as malathion, parathion methyl, monocrotopos, and dichlorvos. The results show that, among the zeolite‐based biosensors investigated in this study, the nanocrystalline titanosilicate‐based acetylcholinesterase biosensor exhibited the highest electrocatalytic activity. The nanocrystalline titanosilicate‐based acetylcholinesterase biosensor exhibited excellent sensitivity, selectivity, stability, linear range, and limit of detection. The analytical performance of the developed sensor was demonstrated in the determination of these pesticides in a range of real samples (apples, cabbages, tap water, and river water) with satisfactory recovery.

Effect of surface modification on the adhesion enhancement of electrolessly deposited Ag-PTFE antibacterial composite coatings to polymer substrates

Coupling agent 3-amino propyl triethoxy silane (γ-APTS) was facilely grafted onto silicon rubber through UV irradiation to form the self-assembly monolayer (SAM). N atoms with lone pairs of electrons in the coupling agent then anchored the silver atoms during electroless plating and produced antibacterial coatings with remarkably improved adhesion to substrates. The grafting of coupling agent was verified by X-ray photoelectron spectroscopy (XPS), the coatings adhesion was tested according to ASTM D 3359-02 and their antibacterial activity was characterized by inhibition halo test. The composition of the composite coatings was investigated by energy dispersive X-ray spectrometer (EDS). The surface morphology was revealed by Atom Force microscopy (AFM). The results showed that the adhesion of Ag-PTFE coatings with strong and stable antibacterial activity was tremendously improved to silicon rubber substrates.

Optimization of tetracycline hydrochloride adsorption on amino modified SBA-15 using response surface methodology

Several researchers are focused on preparation of mesoporous silica as drug carriers with high loading efficiency to control or sustain the drug release. Carriers with highly loaded drug are utilized to minimize the time of drug intake. In this study, amino modified SBA-15 was synthesized through grafting with amino propyl triethoxy silane and then loaded with tetracycline hydrochloride. The drug loading was optimized by using the response surface method considering various factors including drug to silica ratio, operation time, and temperature. The drug to silica ratio indicated as the most influential factor on the drug loading yield. Further, a quadratic polynomial equation was developed to predict the loading percentage. The experimental results indicated reasonable agreement with the predicted values. The modified and drug loaded mesoporous particles were characterized by FT-IR, SEM, TEM, X-ray diffraction (XRD), elemental analysis and N2 adsorption–desorption. The release profiles of tetracycline-loaded particles were studied in different pH. Also, Higuchi equation was used to analyze the release profile of the drug and to evaluate the kinetic of drug release. The drug release rate followed the conventional Higuchi model that could be controlled by amino-functionalized SBA-15. Further, the drug delivery system based on amino modified SBA-15 exhibits novel features with an appropriate usage as an anti-bacterial drug delivery system with effective management of drug adsorption and release.

Boronate affinity nanoparticles for RNA isolation.

In this presented paper, boronic acid incorporated poly(HEMA) based nanoparticles were synthesized for RNA adsorption. For this purpose, poly(HEMA) nanoparticles were synthesized by using the surfactant free emulsion polymerization technique. Then, nanoparticles were modified with 3-(2-imidazoline-1-yl)propyl(triethoxysilane) (IMEO) and functionalized with phenylboronic acid (PBA). Prepared nanoparticles were characterized with SEM, FTIR and zeta-size. Optimum RNA adsorption conditions were investigated with different pHs, temperatures and initial RNA concentrations in order to determine the maximum RNA adsorption onto poly(HEMA)-IMEO-PBA nanoparticles. It was also studied that, synthesized nanoparticles could be used for 5 successive reuses and adsorption capacity of the nanoparticles decreased only about 5% at the end of the 5 cycles.

Novel Synthesis of Gold Nanoparticles Supported on Alkyne-Functionalized Nanosilica

A novel, convenient method for the preparation of gold nanoparticles supported on alkyne-functionalized nanosilica is presented. Silica nanoparticles functionalized with alkynyl carbamate moieties (SiO2@Yne) were synthesized by co-condensation of the difunctional organosilane [3-(2-propynylcarbamate)propyl]triethoxysilane (PPTEOS) with tetraethoxysilane (TEOS) in an alkaline medium. The alkynyl-carbamate functionalities present on silica are able to capture the gold precursor HAuCl4, spontaneously reduce it, and stabilize the resulting supported AuNPs, having an average size of ca. 11 nm. The prepared Au-SiO2@Yne was thoroughly analyzed by X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), atomic absorption spectroscopy (AAS), FT-IR, and UV–vis spectroscopy. The catalytic activity of Au-SiO2@Yne was investigated for the reduction of 4-nitrophenol to 4-aminophenol by NaBH4, and kinetic constants k in the order of magnitude of about 10–2 s–1 wer...

In ovo delivery of Newcastle disease virus conjugated hybrid calcium phosphate nanoparticle and to study the cytokine profile induction

In this report, the hybrid calcium phosphate (CaP) nanoparticles were synthesized and functionalized with Newcastle disease virus (NDV). These nanoparticles were synthesized by a combination of co-precipitation and polymerization process and functionalized with amino propyl triethoxy silane before coupling to NDV. The 5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide (MTT) assay of chicken spleen cells incubated with these nanoparticles indicated that, these particles did not exert any significant cytotoxicity. The effects of hybrid CaP nanoparticles on cell cycle were assayed using a flow cytometer. The results demonstrated that the cell viability and proliferation capacity of spleen cells were not affected by hybrid CaP nanoparticles compared with their control cells. The hybrid CaP nanoparticles were characterized by scanning/transmission electron microscopy (SEM/TEM); Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction patterns (XRD), Raman spectroscopy and energy-dispersive X-ray spectroscopy (EDX). These methods revealed that NDV was successfully conjugated on nanoparticles. The ability of the hybrid CaP nanoparticles to induce different cytokine mRNAs in the spleen cells of 18-day old embryonated chicken eggs (ECEs) was studied by quantitative real time polymerase chain reaction (qRT-PCR). NDV conjugated particles induced a high expression of Th1 cytokines such as interferon (IFN)-α, tumor necrosis factor (TNF)-α of and Th2 cytokines, interleukin (IL) 6 and IL-10. Uncoupled NDV induced only Th1 cytokines, IFN-α, INF-γ and TNF-α. The hybrid particles alone did not induce any cytokines. This confirmed that nanoparticle coupling could induce differential cytokine profiles and hence can be used as an alternate strategy to direct favorable immune responses in animals or chickens using appropriate vaccination carrier.

Evaluation of the tensile strength of polypropylene-based composites containing glass wool

In this study, Glass wool which is mainly applied to heat and acoustic insulation was used as reinforcement materials. The composite material samples consisting of glass wool, polypropylene, and maleic anhydride grafted polypropylene were synthesized and the tensile strengths were evaluated. The treatment of glass wool with 3-amino propyl triethoxy silane coupling agent together with epoxy film former enhanced the tensile strength of the composite samples including the glass wool and the tensile strength reached to the same level of the conventional composite samples including chopping continuous glass fiber. Therefore, we concluded that glass wool has a good potential as a reinforcing material in thermoplastic composites.

Synthesis and thermal stability properties of boron‐doped silicone resin

ABSTRACTIn this article, a novel boron‐doped silicone resin (BSR) was synthesized by hydrolysis‐polycondensation method, with propyl‐triethoxysilane (PTES), dimethyl‐diethoxysilane (DMDES), and boric acid (BA) as starting materials, using absolute ethyl alcohol as solvent and hydrochloric acid as catalyst. The structures of the BSR were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), X‐ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). FTIR spectra showed characteristic BOSi and SiOSi stretching modes. XPS and NMR results confirmed further that boron element was doped successfully into the main chains of the silicone resin as SiOB bond motifs, and hydroxyl groups from BA were condensed properly with SiOH or SiOR to form cross‐linked structure of BSR with narrowed molecular weight distributions in optimum experimental condition. The thermal stability of the BSR was studied by thermogravimetry analysis and derivative thermogravimetry. The thermal degradation temperature of the silicone resin improved greatly after doping element boron into the main chain, and the thermal stability of the BSR was influenced by the content of boron. The thermal degradation mechanism of this BSR was also discussed. The degradation process can be divided into two stages, the weight loss in the first stages may be corresponding to the loss of the small groups and weaker bonds in the chains, such as CH3, and C3H7, the weight loss in the second stage may be corresponding to the loss of the group as OC2H5. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40934.

Effect of hybrid carbon nanotube/short glass fiber reinforcement on the properties of polypropylene composites

The hybrid reinforcement effect of surface treated or untreated carbon nanotube (CNT)/glass fiber (GF); on the morphology, mechanical and electrical properties of polypropylene matrix composites were investigated. Surface treatment of the CNTs was performed by using 3-Amino propyl tri ethoxy silane (APTES). Composites were prepared by means of extrusion and injection molding techniques. FT-IR analysis of the CNT samples revealed the successful surface modification of nanotubes after silane treatment. XRD results showed that chemically functionalized carbon nanotubes have the same cylinder wall and crystalline structure with untreated carbon nanotubes. Tensile and dynamic mechanical analysis (DMA) test results revealed that GF and nanotube reinforced hybrid composites exhibited better tensile strength and modulus values than only GF or CNT reinforced composites. According to all these results, it can be concluded that simultaneous usage of glass fiber and carbon nanotube in the composites increases the reinforcing ability of nanotubes in polymer composites.

Formulation of Newcastle disease virus coupled calcium phosphate nanoparticles: An effective strategy for oculonasal delivery to chicken

In this report, calcium phosphate (CaP) nanoparticles were synthesized by continuous flow method using β-cyclodextrin (β-CD) as a medium and functionalized with amino propyl triethoxy silane (APTES). The blood biocompatibility of the nanoparticles was assessed using the whole blood haemolysis, erythrocytes haemolysis and erythrocyte aggregation tests. Based on the results, we found that the synthesized β-CD–CaP nanoparticles did not cause any remarkable toxic effect. The 5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide (MTT) assay of chicken peripheral blood mononucleated cells (PBMCs) incubated with these nanoparticles indicated that these particles did not exert any significant cytotoxicity. The aminosilane functional group modified β-CD–CaP was used as tool for coupling of Newcastle disease virus (NDV). The NDV conjugated nanoparticles were confirmed by using Fourier transformed infrared spectroscopy, X-ray diffraction patterns, Raman spectroscopy differential scanning calorimetry and energy-dispersive X-ray spectroscopy. Immunogenicity trials in chickens proved that β-CD–CaP-NDV used as a vaccine was better than the commercial vaccine when given oculonasally during the first 2 weeks post vaccination. The birds vaccinated with the above nano-NDV vaccine were completely protected against virulent NDV challenge. This study confirms that the oculonasal β-CD–CaP-NDV delivery of vaccines is a potential method for enhancing the immune responses of existing commercial vaccines.