Modified With 3-mercaptopropyltrimethoxysilane Research Articles

Synergistic effects of (3-mercaptopropyl)trimethoxysilane and citric acid on the improvement of water vapor barrier performance of polyvinyl alcohol/xylan packaging films

The application of polysaccharide-based films is limited due to core problems, such as poor water vapor barriers and flexibility. From this perspective, silane coupling agents have recently attracted particular interest because of their insensitivity to moisture. However, it may cause poor mechanical properties due to the aggregation of silane coupling agents within the materials. Here, we report a collaborative modification protocol to reduce water vapor transmission capacity and to improve the flexibility of xylan-based films. Xylan from sugarcane bagasse was firstly modified with (3-mercaptopropyl) trimethoxysilane (MPTMS) to obtain MPTMS-modified xylan (MSMX), and then blended with polyvinyl alcohol (PVA) using citric acid (CA) as a cross-linker. The PVA/MSMX/CA films were found to be highly impermeable to water vapor and to have robust solvent resistance. With an optimized mass ratio (PVA/MSMX, 2:1), the water vapor permeability (WVP) value was 2.79 × 10−13 (g/cm−1·s ∙Pa), significantly lower than that of previously reported PVA/xylan-based films. The excellent barrier properties were attributed to the “torturous path effect”. Meanwhile, the elongation at break increased up to 480 %, showing a 2-fold enhancement compared to that of PVA/xylan films. This study revealed a great potential of using the PVA/MSMX/CA films as packaging materials for moisture susceptible drugs, food, and electronic components.

An efficient synthesis of acidic mesoporous materials

Abstract Ordered mesoporous silica of SBA-15 type was modified with 3-(trihydroxysilyl)-1-propanesulfonic acid (TPS) in order to obtain a solid acid catalyst. The structure and surface properties of the materials obtained were compared with those of SBA-15 silica modified with (3-mercaptopropyl)trimethoxysilane (MPTMS). For this purpose the samples were examined by low temperature N2 adsorption/desorption, XRD, TEM, FTIR, XPS and elemental analysis. Successful incorporation of TPS species on the silica surface was proved. The catalytic activity of the materials obtained was investigated in acetic acid esterification with n-butanol and n-hexanol. Despite a lower concentration of acidic sites, TPS-modified materials showed a superior catalytic behavior over MPTMS modified sample. Moreover, the TPS containing catalysts showed a stable catalytic activity after drying and application in subsequent process.

Impact of alumina particles on the morphology and mechanics of hybrid wood plastic composite materials

Hybrid composite panels of Wood-Plastic Composites (WPC) consisting of wood and poly (methyl methacrylate) (PMMA) were reinforced with alumina particles and made by ?hot pressing? method. Alumina-based particles were made by sol-gel technique. The particles were characterized by the X-ray diffraction (XRD). The resulting alumina particles were modified with (3mercaptopropyl) trimethoxysilane (MPTMS), in order to obtain better mechanical properties of the composite relative to the composite with unmodified alumina particles. The aim of this work was to study the influence of composite structure and the moisture absorption on bending and the impact properties of the hybrid composite. The bending and impact tests revealed that modulus of elasticity and absorbed energy of deformation increased with modification of alumina and slightly decrease after moisture absorption.

Synthesis of polyaluminum hydroxide on silica spheres for effective fire retardant

AbstractUntil recent years, the majority of flame retardants have been halogen‐containing compounds. Although halogen compounds slow down the flame spread and reduce the fire growth, they increase the release of toxic gases, such as CO and HX (hydrogen halide), are carcinogenic and toxic chemicals, and accumulate environment. The authors carried out the synthesis of polyaluminum hydroxide on silica spheres for effective fire retardant. Large surface area of nanosilica spheres was utilized for improve the fire retardancy. The surface of silica spheres was modified with 3‐mercaptopropyltrimethoxysilane (MPTMS) and polyaluminum hydroxide. The field emission scanning electron microscope images showed that the amount of aluminum hydroxide increased with increasing the amount of AlCl3. The characteristic absorption peaks of Al–OH, Si–OH, Si–O–Si, Si–O, –CH, Si–O–C, and Si–O–Al were observed. The existence of sulfur indicated the surface of silica spheres were modified with MPTMS. The small amount of Cl implied that most of the Al–Cl3 were hydrolyzed.

The effect of electron irradiation on the structure and the optical properties of silver particulate films deposited on modified thermoplastic polymer substrates

The silver (Ag) particulate films are prepared by the vacuum evaporation onto polystyrene (PS) substrates modified with 3-mercaptopropyltrimethoxysilane (MPTMS), pre-irradiated with the 8-MeV electron beam, held at a temperature 453 K. The effect of organosilane and electron irradiation dose on the Ag particulate structure is studied through optical spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) with selected area electron diffraction (SAED) pattern, atomic-force microscopy (AFM), and X-ray diffraction (XRD). The flat spectrum observed for the lower irradiation doses may be due to the formation of the clusters of different sizes and shapes. The band shift toward the higher wavelength is attributed to the increased aggregation leading to the formation of the larger-sized nanoclusters. A long tail extending to the higher wavelength region is also observed due to aggregation process. The FESEM studies indicate the formation of the silver nanoclusters. The decrease in the particle size with the increase in irradiation dose as seen through TEM studies is interpreted on the basis of polymer–metal particle interaction caused by the free radicals formed due to the electron irradiation of the MPTMS-modified PS substrates. The SAED pattern shows the crystalline nature of the silver particles formed on the pure PS and the MPTMS-modified PS substrates irradiated with the electron beam. The AFM studies show an increase in the average surface roughness of the silver films with the electron irradiation dose and the MPTMS concentration. XRD indicated the polycrystalline nature of silver film on the pre-irradiated PS substrates and formation of nanocrystallites of silver with preferred orientation on the MPTMS-modified PS substrates pre-irradiated with electron beam.

Preparation and physical properties of functionalized graphene/waterborne polyurethane UV-curing composites by click chemistry

Functionalized graphene nanoplatelets (f-GNS) were modified with (3-mercaptopropyl)trimethoxysilane (MPTMS) to enhance their compatibility with the polyurethane coating matrix. The results of Fourier transform infrared spectroscopy, AFM, Raman and XRD showed that the MPTMS was successfully attached onto the surface of the graphene nanoplatelets. Functionalized graphene/waterborne polyurethane acrylate (f-GNS/WPUA) nanocomposites were fabricated by UV-curing technology. The SEM and TEM images indicated that f-GNS could be well dispersed in the polymer matrix and improved the interfacial adhesion. With the incorporation of 1 wt% f-GNS, the thermal decomposition temperature of the composites was increased by 25 °C. Meanwhile, the conductivity, hydrophobicity and tensile strength were increased. When the load was further increased, the performance of the composites showed varying degrees of reduction. However, the dielectric loss tangent (tan δ) could be maintained at 0.08 or less and the electromagnetic shielding factor of the composites reached from 5 to 36 dB, showing a good electromagnetic shielding effect at a high content (2.5 wt% f-GNS). It was considered that f-GNS could disperse in the waterborne polyurethane well and crosslink with the polyurethane. © 2016 Society of Chemical Industry

Novel removal of Anthracene from oil-contaminated water by synthesized modified magnetic nano-particles

Novel magnetic nanoparticles (MNPs) modified with (3-mercaptopropyl)-trimethoxysilane (MPTMS), grafted with allyl glycidyl ether and coupled with beta naphthol, were prepared for removal of anthracene in aqueous solutions. The grafted MNPs were characterized by transmission electron microscopy (TEM), infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The modified MNPs contributed to enhancement of the adsorption capacity and were prepared by co-precipitation. The modified MNPs were characterized by TEM, FT-IR and TGA and the adsorption and kinetic behavior of anthracene on the modified MNPs was examined. It was shown that the nano-adsorbent optimized adsorption capacity is at pH 7. Three kinetics models: pseudo-first-order, pseudo-second-order, and intraparticle diffusion were used to investigate the adsorption mechanism of the anthracene onto the modified MNPs. The best fit was obtained for the pseudo-second-order model. The synthesized nano adsorbent can be considered as a new method for anthracene adsorption in contaminated water with the benefit of fast removal by applying a magnetic field.

Preparation of nanoparticles-modified silica monolith for on-column surface enhanced Raman spectroscopy

A novel silica monolith modified with Ag/Au nanoparticles was prepared for the on-column surface enhanced Raman spectroscopy (SERS). The bare monolithic silica column was prepared from in-situ co-condensation of tetraethoxysilane (TMOS) and methyl trimethoxysilane (MTMS) in the presence of polyethylene glycol (PEG) via a sol-gel process in the capillary, and was chemically modified with (3-mercaptopropyl) trimethoxysilane (MTPMS), followed by immobilization of Ag/Au nanoparticles. Transmission electron microscopy (TEM) and UV-Vis spectrometer were used to collect the TEM images and the extinction spectra of the nanoparticles colloid, respectively. Scanning electron microscope (SEM) was utilized to record the morphology of the silica monolith The authros used p-aminothiophenol (PATP) as a probing molecule, and the SERS effect was investigated on Au/Ag nanoparticle-modified silica monolith under the excitation line of 633 and 532 nm, respectively. It is concluded that nanoparticle-modified silica monoliths will have broad application to the on-site detection of food and water contaminants in the field.

Effect of 3-mercaptopropyltrimethoxysilane on Surface Finish and Material Removal Rate in Chemical Mechanical Polishing

Chemical Mechanical Polishing (CMP) is used in polishing of glass and ceramic surfaces as well as in integrated circuit manufacturing to remove excess material and provide a globally planarized wafer surface. One of the critical consumables in the CMP process is abrasive slurry typically containing both abrasives and chemicals acting together. To improve the chemical mechanical polishing performance, abrasive particles of acidic, basic and neutral colloidal silica were modified with 3-mercapto propyl tri methoxysilane (MPTMS) through silanization reaction with surface hydroxyl group. The modified abrasive slurries were used for chemical mechanical polishing of glass substrate. The results obtained indicate that the modified colloidal silica nanoparticlesslurry (MPTMS + Acidic Colloidal silica)with better dispersibility and stability in aqueous fluids resulted in improved surface finish and material removal rate than conventional process. The results of comparative study between three modified slurries showed that modified resulted (MPTMS + Acidic Colloidal silica) has better surface finish and more material removal rate of 6micron in four hours with surface finish in the range of 0.4nm -0.7nm, which proved to be better than the conventional process.

The production of biofuels additives on sulphonated MCF materials modified with Nb and Ta—Towards efficient solid catalysts of esterification

The aim of this work was to compare the properties of niobium (Si/Nb=118) and tantalum (Si/Ta=121) containing mesostructured cellular foams (MCF) modified with (3-mercaptopropyl) trimethoxysilane (MPTMS) in one-pot synthesis and the application of materials obtained in acetic acid esterification with glycerol. TaMCF materials were prepared for the first time. Catalysts were characterized by different techniques: N2 adsorption, XRF, elemental and thermal analyses, FTIR+pyridine adsorption and titration of acid sites. New catalysts have showed an excellent catalytic activity in the acetic acid esterification with glycerol to yield triacetylglycerol, also known as triacetin (a valuable additive for biodiesel composition). The influence of modifiers on the number and strength of acidic centres in the materials obtained was found and discussed in details in the paper. The strength of Brønsted acid centres (BAS) was estimated by the interaction of organosilane with transition metal via the use of methoxy groups from MPTMS. The highest concentration of acidic sites determined by NaOH titration was obtained on tantalum modified MCF, whereas the highest strength of BAS was observed on MP-NbMCF sample. The catalytic behaviour of MPTMS and Nb modified MCF samples was comparable to that observed for Amberlyst 15 and better than that of Nafion SAC 13. The materials obtained could be reused and showed stable catalytic features in subsequent cycles. The addition of tantalum allows obtaining a new catalyst with high efficiency of thiol species oxidation (higher than reported before for other catalysts). MPTMS modified TaMCF material appeared to be attractive for further study in different reactions requiring high concentration of acidic centres.

Silica encapsulation of thiol-stabilized lead selenide (PbSe) quantum dots in aqueous solution

Silica encapsulation of lead selenide quantum dots (PbSe QDs) in aqueous solution is reported. Thioglycolic acid (TGA) stabilized PbSe QDs were modified with 3-mercaptopropyl trimethoxysilane (MPS) through vigorous stirring in water for 18–24h in alkaline solution (pH 10.4–10.6). Silica shell was developed by controlled deposition and precipitation of silicates from sodium silicate solution onto MPS modified QDs surfaces. TEM images showed multiple PbSe QDs encapsulated in silica shell. The size of PbSe–SiO2 core–shell nanocrystals was estimated to be 25–30nm by TEM. Elemental compositions (Pb, Se and Si) were investigated by EDX analysis. The purified colloids of PbSe–SiO2 QDs were stable for months when kept at 4°C.

Synthesis, characterization and modification of functionalized pyrimidine stabilized gold nanoparticles on ITO electrode for the determination of tannic acid

This paper describes the synthesis of 4-amino-6-hydroxy-2-mercaptopyrimidine capped gold nanoparticles (AHMP-AuNPs) in aqueous medium and their immobilization on indium tin oxide (ITO) electrode modified with (3‐mercaptopropyl)trimethoxysilane (MPTS) sol–gel for the determination of tannic acid (TA). The high resolution transmission electron microscopy (HR-TEM) images show that the particles are spherical in shape with a diameter of ~6nm. The heterogeneous electron transfer rate constant (ket) of [Fe(CN)6]3−/4− at ITO/MPTS/AHMP-AuNPs electrode was found to be 1.14×10−7m/s. This value was much higher than the values obtained at ITO/MPTS (4.94×10−9m/s) and bare ITO (8.79×10−8m/s) electrodes, indicating that the electron transfer reaction was faster at AuNPs modified electrode. Further, the ITO/MPTS/AHMP-AuNPs electrode shows excellent electrocatalytic activity toward TA oxidation when compared to bare ITO electrode. This was understood from the obtained higher heterogeneous rate constant (ks) value at AuNPs modified electrode (7.35×10−5m/s) than at bare ITO electrode (5.45×10−6m/s). Using the amperometry method, detection of 20nmol/L TA was achieved. The practical application of the present method was demonstrated by determining the concentration of TA in commercial beer samples.

Facile synthesis and responsive behavior of PDMS‐b‐PEG diblock copolymer brushes via photoinitiated “thiol‐ene” click reaction

AbstractWe present herein a mild and rapid method to create diblock copolymer brushes on a silicon surface via photoinitiated “thiol‐ene” click reaction. The silicon surface was modified with 3‐mercaptopropyltrimethoxysilane (MPTMS) self‐assembled monolayer. Then, a mixture of divinyl‐terminated polydimethylsiloxane (PDMS) and photoinitiator was spin‐coated on the MPTMS surface and exposed to UV‐light. Thereafter, a mixture of thiol‐terminated polyethylene glycol (PEG) and photoinitiator were spin‐coated on the vinyl‐terminated PDMS‐treated surface, and the sequent photopolymerization was carried out under UV‐irradiation. The MPTMS, PDMS, and PEG layers were carefully identified by X‐ray photoelectron spectroscopy, atomic force microscopy, ellipsometry, and water contact angle measurements. The thickness of the polydimethylsiloxane‐block‐poly(ethylene glycol) (PDMS‐b‐PEG) diblock copolymer brush could be controlled by the irradiation time. The responsive behavior of diblock copolymer brushes treated in different solvents was also discussed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Organosilanes affecting the structure and formation of mesoporous cellular foams

Purely siliceous and niobium-containing mesoporous molecular foams (MCFs) were synthesized by modifying a standard synthesis route. This was accomplished by decreasing considerably the content of chloride ions in the gel. The samples prepared under such conditions contained the MCF and SBA-15 phases. Mesostructured cellular foams were modified with (3-mercaptopropyl)trimethoxysilane (MPTMS) and (3-aminopropyl)trimethoxysilane (APTMS) via the direct synthesis, with increased efficiency of formation of the spherical MCF phases. All the materials obtained were characterized by XRD, sorption of nitrogen, FT-IR, UV–Vis, thermogravimetric analysis, 29Si MAS NMR, 13C CP/MAS NMR, and electron microscopy. We demonstrated that organosilanes added at the end of the synthesis procedure play a double role; as a source of the anchored catalytic active species (propylamines and propylsulfonic chains) and a source of methanol released during the interaction between MPTMS (APTMS) and hydrolyzed tetraethyl orthosilicate (TEOS). The methanol obtained in this way acts as a co-surfactant increasing the activity of ethanol released during hydrolysis of TEOS and enhancing the transformation of cylindrical SBA-15 towards the spherical MCF phase. Finally, it was shown that niobium species enhanced the oxidation of thiol groups in MPTMS towards sulfonic species and also affected slightly the morphology of the samples. The presence of niobium moieties did not influence, however, the formation of the pure MCFs mesostructured materials and their structural parameters.

Novel Photofunctional Multicomponent Rare Earth (Eu3+, Tb3+, Sm3+ and Dy3+) Hybrids with Double Cross‐linking Siloxane Covalently Bonding SiO2/ZnS Nanocomposite

Zinc sulfide (ZnS) quantum dot is modified with 3-mercaptopropyltrimethoxysilane (MPTMS) to obtain MPTMS functionalized SiO(2)/ZnS nanocomposite. Novel rare earth/inorganic/organic hybrid materials are prepared by using 3-(triethoxysilyl)-propyl isocyanate (TESPIC) as an organic bridge molecule that can both coordinate to rare earth ions (Eu(3+), Tb(3+), Sm(3+) and Dy(3+)) and form an inorganic Si-O-Si network with SiO(2) ZnS nanocomposite after cohydrolysis and copolycondensation through a sol-gel process. These multicomponent hybrids with double cross-linking siloxane (TESPIC-MPTMS) covalently bonding SiO(2)/ZnS and assistant ligands (Phen = 1,10-phenanthroline, Bipy = 2,2'-bipyridyl) are characterized and especially the photoluminescence properties of them are studied in detail. The luminescent spectra of the hybrids show the dominant excitation of TESPIC-MPTMS-SiO(2)/ZnS unit and the unique emission of rare earth ions, suggesting that TESPIC-MPTMS-SiO(2)/ZnS unit behaves as the main energy donor and effective energy transfer take place between it and rare earth ions. Besides, the luminescent performance of Bipy-RE-TESPIC-MPTM-SiO(2)/ZnS hybrids are superior to that of Phen-RE-TESPIC-MPTMS-SiO(2)/ZnS ones (RE=Eu, Tb, Sm, Dy), which reveals that Bipy or Phen only act as structural ligand within the hybrid systems.

Direct Growth of Gold Nanorods on Gold and Indium Tin Oxide Surfaces: Spectral, Electrochemical, and Electrocatalytic Studies

The surfactant-assisted seed-mediated growth method was used for the formation of gold nanorods (GNRs) directly on gold (Au) and indium tin oxide (ITO) surfaces. Citrate-stabilized ∼2.6 nm spherical gold nanoparticles (AuNPs) were first self-assembled on ITO or Au surfaces modified with (3-mercaptopropyl)-trimethoxysilane (MPTS) sol−gel film and then immersed in a cationic surfactant growth solution to form GNRs. The growth of GNRs on the MPTS sol−gel film modified ITO surface was monitored by UV−visible spectroscopy. The ITO surface with the attached spherical AuNPs shows a surface plasmon resonance band at 550 nm. The intensity of this absorption band increases while increasing the immersion time of the AuNP-modified ITO surface into the growth solution, and after 5 h, an additional shoulder band around 680 nm was observed. The intensity of this shoulder band increases, and it was shifted to longer wavelength as the immersion time of the AuNP-modified ITO surface into the growth solution increases. After 20 h, a predominant wave at 720 nm was observed along with a band at 550 nm. Further immersion of the modified ITO surface into the growth solution did not change the absorption characteristics. The bands observed at 550 and 720 nm were characteristics of GNRs, corresponding to transverse and longitudinal waves, respectively. The AFM images showed the presence of GNRs on the surface of the MPTS sol−gel modified ITO surface with a typical length of ∼100−120 nm and a width of ∼20−22 nm in addition to a few spherical AuNPs, indicating that seeded spherical AuNPs were not completely involved in the GNRs’ formation. Finally, the electrocatalytic activity of the surface-grown GNRs on the MPTS sol−gel film modified Au electrode toward the oxidation of ascorbic acid (AA) was studied. Unlike a polycrystalline Au electrode, the surface-grown GNR-modified electrode shows two well-defined voltammetric peaks for AA at 0.01 and 0.35 V in alkaline, neutral, and acidic pHs. The cause for the observed two oxidation peaks for AA was due to the presence of both nanorods and spherical nanoparticles on the electrode surface. The presence of spherical AuNPs on the MPTS sol−gel film oxidized AA at more positive potential, whereas the GNRs oxidized AA at less positive potential. The observed 340 mV less positive potential shift in the oxidation of AA suggested that GNRs are better electrocatalysts for the oxidation of AA than the spherical AuNPs.

Photophysical Properties of a Novel Organic–Inorganic Hybrid Material: Eu(III)‐β‐Diketone Complex Covalently Bonded to SiO2/ZnO Composite Matrix

In this article, dibenzoylmethane (DBM) was first grafted with the coupling reagent 3-(triethoxysilyl)-propyl isocyanate (TESPIC) to form precursor DBM-Si, and ZnO quantum dot was modified with 3-mercaptopropyltrimethoxysilane (MPS) to form SiO(2) /ZnO nanocomposite particle. Then the precursor DBM-Si and the terminal ligand 1,10-phenthroline (phen) were coordinated to Eu(3+) ion to obtain ternary hybrid material phen-Eu-DBM-SiO(2) /ZnO after hydrolysis and copolycondensation between the tetraethoxysilane (TEOS), water molecules and the SiO(2) /ZnO network via the sol-gel process. In addition, for comparison, the binary hybrid material with SiO(2) /ZnO network and ternary hybrid material with pure Si-O network were also synthesized, denoted as Eu-DBM-SiO(2) /ZnO and phen-Eu-DBM-Si, respectively. The results reveal that hybrid material with SiO(2) /ZnO network phen-Eu-DBM-SiO(2) /ZnO exhibits the stronger red light, the longer lifetimes and higher quantum efficiency than hybrid material with pure Si-O network phen-Eu-DBM-Si, suggesting that SiO(2) /ZnO is a favorable host matrix for the luminescence of rare earth complexes.

Large‐Sized Fabrication of Tunable Plasmonic Electrodes Via Electrodeposition

AbstractElectrodeposition method, a simple, cheap, and flexible approach, to fabricate gold nanoparticle (Au NPs) films with an area larger than 1 cm2 on indium tin oxide (ITO) electrodes modified with (3‐mercaptopropyl) trimethoxysilane (MPTMS) was presented. Size‐controllable and high loading Au NPs were obtained, which were characterized by field‐emission scanning electron microscopic (FESEM) and UV‐vis spectroscopy. Our current method provides a versatile and facile pathway to fabricate large‐scale metal nanoparticles thin film, enhancing alternatives for academic investigation and industrial application.

Ni(II) removal from aqueous effluents by silylated clays

Industrial effluents discharged in water bodies without proper treatment contribute to water pollution by potentially toxic metal ions. Considering that the legislation for discarding of such effluents is getting more and more rigorous, the development of efficient processes for the treatment of industrial effluents is of great interest. A study on the capacity of metal retention by silylated-modified clays was carried out with the aim to evaluate the efficiency of this application. K10 clay was modified with 3-mercaptopropyltrimethoxysilane (MPS) and tested in batch removal processes. We investigated the sorption process, obtaining isotherms and kinetics of adsorption and the influence of pH, the desorption process and the metal recovery. It was observed that the modified clay presents fast retention and good capacity of both adsorption and desorption. The use of K10/MPS as adsorbent shows to be more adequate in effluent final polishment, after a conventional treatment, or when Ni(II) initial concentration in the effluent is low enough to permit its adequate removal by conventional methods.

SILAR Deposition of CdS Thin Films on Glass Substrates Modified with 3‐Mercaptopropyltrimethoxysilane

Glass substrates modified with 3‐mercaptopropyltrimethoxysilane (MPS) were used to deposit CdS thin films in the process of successive ionic layer adsorption and reaction (SILAR). The films were characterized by X‐ray diffraction, optical absorption, and atomic force microscopy (AFM). AFM showed that the modified substrates were in favor of the growth of the films by comparison with the unmodified ones. The depositing rate of the films was faster on modified substrates than on unmodified ones.