Influence Of Silane Coupling Agent Research Articles

The influence of doping with different surface modified SiO2 nanoparticles on the dielectric properties of natural ester insulating oil

Nanoparticles are presently considered to be high-potential filler materials in insulation medium. Surface-modified nanoparticles can not only improve the compatibility between nanoparticles and insulation liquid but also enhance the dielectric properties. Herein, models of soybean oil-based natural ester insulation oil doped with two silane coupling agents (A151, KH550) modified SiO2 were established, respectively. Molecular dynamics and DFT first principles were applied to explore the effect of two nanoparticles on the dielectric properties of liquid-insulation medium. The results showed that two types of nanoparticles can restrict the diffusion of water molecules by forming hydrogen bonds, while the number of hydrogen bonds in KH550–SiO2 is one-third more than that in A151-SiO2, and the interaction energy is lower, demonstrating a stronger adsorption effect on water molecules. Moreover, surface electrostatic potential and frontier molecular orbitals showed that KH550–SiO2 have a higher adsorption on charged particles in natural ester insulation oil, which can further inhibit the development of streamer discharge in the liquid insulation medium, improve its dielectric property and delay the aging and deterioration of natural ester insulation oil. This study extends our knowledge into the influence of silane coupling agents modified SiO2 nanoparticles on the dielectric performance of liquid insulation materials from a microscopic perspective.

Influence of Silane Coupling Agent and Anionic Dispersant on the Dispersion Effect of Silicon Carbide Particles.

Silicon carbide (SiC), as a widely used material, has great properties. To improve the flowability of ultrafine silicon carbide slurry, this study used sodium humate, tetramethylammonium hydroxide (TMAH), and N-(β-monoaminoethyl)-γ-aminopropyltrimethyl(ethoxysilane) (KH792) to modify the ultrafine silicon carbide powder produced by Qingzhou Micro Powder Company. The effects of different modifiers on improving the flowability of ultrafine silicon carbide slurry were investigated by means of viscosity tests, sedimentation experiments, and SEM observations. Their modification mechanisms were investigated by means of zeta potential tests, XPS tests, and so on. In this paper, the initial modification of SiC was carried out with KH792, followed by the secondary modification with anionic and cationic modifiers (tetramethylammonium hydroxide and sodium humate), and the optimal modification conditions were investigated by means of a viscosity test, which showed that the lowest viscosity of the modified SiC reached 0.076 Pa·s and that the absolute maximum value of the zeta potential increased from 47.5 at the time of no modification to 63.7 (maximum values) at the time of modification. This means it has an improved surface charge, which improves dispersion. The adsorption results of the modifier on the silicon carbide surface were also demonstrated by the XPS test results.

Influence of silane coupling agents on the interfacial structure and properties of modified polypropylene/aluminum alloy composites prepared by hot-press molding

ABSTRACT Polymer-metal hybrids were prepared by using the ultrasonic-assisted hot-press molding process. The surface of the aluminum alloy is anodized to produce nano-pores with a pore size distribution of 60 to 210 nm. The surface of the anodized aluminum alloy is soaked with a silane coupling agent solution to alter its surface polarity. In addition, PP-g-MAH was used to alter the polarity of polypropylene. The structure and properties of the composites were investigated by tensile shear tests, the microstructure of the bonding interface, and elemental analysis. The results show that adding silane coupling agents can create a chemical connection based on the mechanical interlocking structure of the composite bonding interface, leading to an increase in tensile shear strength. When the aluminum alloy surface was treated with a silane coupling agent with a volume fraction of 4%, the tensile shear strength reached 21.02 MPa, increasing by 20.32% compared to the specimen without the silane coupling agent treatment.

The influence of silane coupling agents on the properties of α-TCP-based ceramic bone substitutes for orthopaedic applications.

Biomaterials based on α-TCP are highly recommended for medical applications due to their ability to bond chemically with bone tissue. However, in order to improve their physicochemical properties, modifications are needed. In this work, novel, hybrid α-TCP-based bone cements were developed and examinated. The influence of two different silane coupling agents (SCAs) - tetraethoxysilane (TEOS) and 3-glycidoxypropyl trimethoxysilane (GPTMS) on the properties of the final materials was investigated. Application of modifiers allowed us to obtain hybrid materials due to the presence of different bonds in their structure, for example between calcium phosphates and SCA molecules. The use of SCAs increased the compressive strength of the bone cements from 7.24 ± 0.35 MPa to 12.17 ± 0.48 MPa. Moreover, modification impacted the final setting time of the cements, reducing it from 11.0 to 6.5 minutes. The developed materials displayed bioactive potential in simulated body fluid. Presented findings demonstrate the beneficial influence of silane coupling agents on the properties of calcium phosphate-based bone substitutes and pave the way for their further in vitro and in vivo studies.

The modification mechanisms of silane coupling agent (SCA) on the physical properties of thermosetting polyurethane asphalt binder (PUAB)

• The addition of SCA enhanced the physical properties of PUAB . • A viscosity model based on the dual-Arrhenius theory was established. • SCA had physical and chemical connection on the polyurethane-asphalt interface. • A deformation layer formed by SCA was a significant role in PUAB system. The paper attends to investigate the influence of silane coupling agent ( SCA ) on the novel thermosetting polyurethane ( PU ) asphalt binder ( PUAB ). Initially, the storage stability, thermal stability and viscosity of PUAB are evaluated with the separation test, thermogravimetric analysis ( TGA ) and Brookfield viscosity, respectively. Then the mechanical properties, elastic recovery performance and permanent deformation resistance of PUAB are examined by the universal testing machines and dynamic shear rheometer ( DSR ), respectively. Finally, the modification mechanism is analyzed by Fourier transform infrared spectroscopy ( FTIR ). The results show that the thermal stability and storage stability of PUAB are improved by adding SCA . Then, a viscosity model based on the dual-Arrhenius theory is established and well predicts the effect of SCA on viscosity-time relationship of PUAB . Furthermore, the addition of SCA significantly enhance mechanical behaviors of PUAB where the complex modulus of PUAB rise, a 16 % of tensile strength increase and a 98.4 % of the elastic recovery (58 °C/0.1 kPa) are reached with 1 % SCA adding. Data from chemical investigations suggest that SCA connect between asphalt and PU to form groups of oxazolidinone, then promoting better compatibility. Then formed deformation layer can relieve the stress and improve the interfacial bond strength. Accordingly, this finding provides a feasible approach to the performance improvement of PUAB .

RETRACTED: Effect of Silane Coupling Agent on the Mechanical Properties of Oil Palm Frond Fiber Composite

Retracted article: In this study, the influence of silane coupling agent on the matrix/ fiber interface bonding and its effect to the mechanical properties of oil palm frond fiber reinforced polyester composites were investigated. Tensile and flexural properties of the composites were studied at 0 - 10.2 volume fraction (% fiber content). Results showed an increasing trend in tensile modulus while tensile strength and flexural strength reduced as the fiber content increased. Higher tensile modulus values were observed in silane treated fiber composites due to additional fiber/ matrix interaction and increment in polyester molecular chain mobility constraint. Reduction in tensile strength is caused by decrease in the matrix crystallinity and formation of stress concentration spots emerging from interface discontinuity. These obstructions, however, were reduced by fiber surface modification, which improved the tensile strength. Enhanced fiber dispersion upon surface modification was unveiled through scanning electron micrograph images.

Influence of silane coupling agent on the mechanical performance of flowable fibre-reinforced dental composites

ObjectivesThis experimental investigation explored the optimisation of silane treatment of surface-modified S-2 Glass fibres in restorative dental composites for improved mechanical performance. The influence of optimum amount of silane to improve the interfacial adhesion at the fibre-matrix interfaces and its effect on the mechanical properties of the restorative composites were explored. MethodsS-2 Glass fibres of 5 μm diameter and 250 μm length were surface modified using the acid etching technique. The etched fibres were then treated with either 3-methacryloxypropyltrimethoxysilane (3-MPS), 3-Glycidoxipropyltrimethoxysilane (3-GPS) or 8-methacryloxyoctyltrimethoxysilane (8-MOTS) at varying molar % / wt% concentrations. Fibres that were not silanised with any silane coupling agents were used as the control sample. The silanol content of each mixed silane was observed using Fourier transform infrared (FT-IR) spectroscopy analysis. Fibres (5 wt%) with optimised molar% / wt% silane coupling concentration were added to UDMA/TEGDMA dental resin. Mechanical properties such as flexural strength, flexural modulus, and the breaking energy of the materials were evaluated using a comprehensive experimental programme. ResultsFTIR spectrum of glass fibre silanised with each silane coupling agent revealed many peaks from 3800 to 1400 cm−1, indicative of -CH3, -CH2, and CO bonding, suggesting the proper silanization of the fibre. The contact angle test revealed that optimum wt% concentration of 3-MPS, 3-GPS and 8-MOTS were 0.5%, 0.8% and 1.4% respectively. The flexural strength of the fibre-reinforced with optimum concentration of 3-MPS (DC-3-MPS_0.5%) increased by 7.0% compared to those of the 2 wt% concentration of 3-MPS fibre-reinforced composite (DC-3-MPS_2.0%). While the flexural strength of optimum concentration 8-MOTS grafted dental resin composites (DC-8-MOTS_1.4%) were 9.9% higher than that of 2 wt% concentration 8-MOTS grafted dental resin composite (DC-8-MOTS_2.0%) and the flexural strength of optimum concentration of 3-GPS (DC-3-GPS_0.8%) was 7.5% higher when compared to that of 2 wt% concentration 3-GPS grafted dental resin composites (DC-3-GPS_2.0%). A concurrent trend was found while investigating the fracture behaviour of the dental composite with optimum wt% concentration of each silane coupling agent against its corresponding higher wt% concentrations. The ANOVA results showed that the optimum fibre-reinforced dental composites grafted with 8-MOTS showed better mechanical behaviour when compared to 3-GPS and 3-MPS. SignificanceThe interfacial adhesion between the fibre and the resin due to silane coupling agents has helped to improve the mechanical properties of the fibre-reinforced dental composite. This is the first experimental study to provide a thorough investigation into the significance of the optimal use of silane coupling agents to treat the S-2 Glass fibres and subsequently the influence on the mechanical performance of the fibre-reinforced flowable dental composites.

Effect of the TiO2 surface modification with 3-glycidyloxypropyltrimethoxysilane on the aggregation of cresyl violet: Application to a dye-sensitized solar cell

Dye aggregation is a typical phenomenon occurring in dye-sensitized solar cells (DSSCs), which causes a decrease in the electron injection efficiency from the photoexcited dye to titanium dioxide (TiO2). As this results in a decrease in the photovoltaic performance, it cannot be ignored in the study of DSSCs. This paper reports a DSSC involving a TiO2 electrode chemically modified by cresyl violet (CV) covalently attached to 3-glycidyloxypropyltrimethoxysilane (GPTMS). The aim of the study is to understand the influence of silane coupling agents (SCAs) on dye aggregation. Aggregation of CV occurring on the TiO2 surface was prevented by GPTMS treatment on the TiO2 surface. This result was revealed by the decreased absorption intensity of the dimeric band observed in the total transmittance spectra. Density functional theory calculations and fluorescence decay curve measurements indicated that the CV covalently attached to GPTMS acts as a photosensitizing dye in DSSCs. As a result, the photovoltaic performance of DSSCs containing CV was enhanced by preventing its aggregation upon GPTMS treatment onto the TiO2 surface (7-fold increase: 0.0020%–0.014%). We concluded that TiO2 surfaces treated with SCAs can help to prevent dye aggregation, and therefore, enhance the photovoltaic performance of DSSCs.

Influence of silane coupling agent and aging on the repair bond strength of dental composites

The objective of this work was to evaluate the effect of different protocols on the shear bond strength (SBS) of repairs made to aged composite resin substrates. Eighty cylindrical composite resin specimens (IPS Empress Direct, Ivoclar-Vivadent) were prepared, and divided into two main groups: in group 1 a silane agent was applied, while in group 2, the silane agent was not applied. Each group was then subdivided into four groups according to the adhesive system used: control, without any adhesive, Single Bond Universal, Tetric Bond Universal, and Clearfil SE Bond. As a reference group, the cohesive strength of the composite resin was determined. After applying the adhesive protocol, the treated surfaces were restored with composite resin cylinders. The specimens were stored in distilled water for 24 h or 6 months at 37 °C and subjected to a SBS test. The data were evaluated using a three-way ANOVA test followed by a Tukey test (α = 0.05). The previous application of silane did not significantly affect the SBS (p = 0.162), on the contrary, the type of adhesive protocol and aging impacted significantly (p < 0.001). The SBS was significantly higher when Clearfil SE Bond was used (p < 0.001), with the values achieved by this group being similar to those of the reference group (p ≥ 0.996). The use of a silane coupling agent before the application of an adhesive does not significantly affect the process of adhesion to an aged resin. The application of a solvent-free adhesive system was able to restore the cohesive strength values of the material.

Effect of silane coupling agent on the rheological and mechanical properties of alkali-activated ultrafine metakaolin based geopolymers

Fluidity modification on geopolymer without changing its compositions is necessary. This study, firstly, investigated the optimal oxides molar ratios of geopolymers, then rheology, rheokinetics, fluidity and mechanical properties tests were conducted to study the influence of silane coupling agent (SCA) on geopolymers. Finally, characterization techniques of SEM, pore size distribution, FTIR and DSC were used to reveal the mechanisms. The results show when SiO2/Al2O3 = 3.4, M2O/Al2O3 = 1, and H2O/M2O = 11, geopolymer’s fluidity reaches 144 mm with the best compressive strength. The addition of 2 wt% SCA can reduce viscosity, increasing the fluidity to 167 mm, while excessive SCA can’t. SCA can also increase the viscosity growth rate and influence the microstructure of geopolymers.

Influence of Silane Coupling Agents on Filler Network Structure and Stress-Induced Particle Rearrangement in Elastomer Nanocomposites.

Filled rubber materials are key in many technologies having a broad impact on the economy and sustainability, the most obvious being tire technology. Adding filler dramatically improves the strength of rubber by reinforcement and tailoring the type of filler, and the chemistry of the interface between the filler and rubber matrix is important for optimizing performance metrics such as fuel efficiency. In a highly loaded, silica-filled, cross-linked model rubber closely mimicking commercial materials, both the filler network structure and the dynamics of the silica filler particles change when the silica surface is modified with silane coupling agents. Reduction in size scales characteristic of the structure is quantified using ultra-small-angle X-ray scattering (USAXS) measurements and the particle dynamics probed with X-ray photon correlation spectroscopy (XPCS). While the structure averaged over the scattering volume changes little with aging after step strain, the dynamics slow appreciably in a manner that varies with the treatment of the silica filler. The evolution of filler particle dynamics depends on the chemical functionality at the silica surface, and observing these differences suggests a way of thinking about the origins of hysteresis in nanoparticle-reinforced rubbers. These microscopic filler dynamics are correlated with the macroscopic stress relaxation of the filled materials. The combination of static and dynamic X-ray scattering techniques with rheological measurements is a powerful approach for elucidating the microscopic mechanisms of rubber reinforcement.

Effect of silane coupling agent modified zeolite warm mix additives on properties of asphalt

In order to evaluate the influence of silane coupling agent modified zeolite warm mix additives on the properties of asphalt, the physical and rheological properties as well as chemical structure of asphalt with zeolite, γ-ammoniapropyltriethoxysilane modified zeolite (KH550-zeolite) and γ-(2,3-epoxypropoxy)propytrimethoxysilane modified zeolite (KH560-zeolite) before and after thin film oven test (TFOT) aging were thoroughly investigated. The results showed that, compared with zeolite, KH550-zeolite and KH560-zeolite made the softening point of asphalt increase more, and whose penetration and ductility decrease less, which indicated that KH550-zeolite and KH560-zeolite (especially KH560-zeolite) could enhance the high-temperature properties and had less effect on the penetration and ductility of asphalt. The temperature susceptibility of asphalt was clearly reduced and the rutting factor (G*/sinδ) was enhanced after the introduction of silane coupling agent modified zeolites compared with zeolite. After the TFOT aging, the performance of asphalt with silane coupling agent modified zeolites (especially KH560-zeolite) had a little change. In a word, KH550-zeolite and KH560-zeolite as warm mix additives had a positive effect on the physical, rheological and anti-aging properties of asphalt.

Influence of silane coupling agent on shear thickening fluids (STF) for personal protection

The present work studied the influence of silane coupling agent in non-Newtonian fluid, in the impact resistance, adhesion and flexibility results. The results of stab performance for Kevlar samples impregnated with silane agent showed results significantly higher than others samples non impregnated, such results are closely associated with the formation of siloxane bonds due to the coupling agent. The impact resistance properties of all samples were tested using drop tower testing, and the flexibility was testes beyond bending angle test. SEM and FTIR analyses were used to verify the chemicals compositions and to evaluate qualitatively the presence of nanoparticles samples. Abrasion test were realized to verify the influence of silane agent of the resistance adhesive of non-Newtonian fluid under samples. The Kevlar samples impregnated with STF and coupling silane presented best flexibility (angle of bending = 30.33°), a significant increase on the dissipation kinetic (penetration depth) in comparing to the others and resistance adhesive of non-Newtonian fluid under samples. Therefore, practically this property remained unalterable in relation to Kevlar samples with STF and Kevlar control.

Influence of silane coupling agent on the synthesis and properties of nanocomposites obtained via in situ catalytic copolymerization of ethylene and propylene in the presence of modified Nafen™ Al2O3 nanofibers

Nanofibers of Al2O3 (commercial product Nafen™), which were modified by various silane coupling agents have been used to create hybrid materials based on copolymer of ethylene and propylene. Nanocomposites were obtained by in situ catalytic copolymerization on the rac-Et(2-MeInd)2ZrMe2/isobutylalumoxane system. Trialkoxysilanes with alkenyl (vinyl and octenyl) and alkyl (octyl) functional groups were used for modification. CP MAS NMR analysis (13C and 29Si) of all modified nanoparticles showed the absence of residual alkoxy groups and allowed to identify the type of formed siloxane groups (mainly T2, T3). EDX analysis of trimethoxyalkenylsilanes modified nanoparticles showed significant contribution of self-condensation reactions, otherwise, in the case of triethoxyoctylsilane condensation with surface AlOH groups prevailed. It is found that octylsilane modification leads to remarkable improvement of mechanical properties (tensile strength - approx. 150%, elongation at break - approx. 50% with regard to neat copolymer) at low nanofiller dosage (0.63 wt %), significantly exceeding those for the materials with alkenylsilane treated nanofibers. In the case of octenylsilane even major decline in mechanical performance was observed. We believe that this behavior is determined by the distribution of nanofiller in the polymer matrix, which is markedly different for different surface treatments. TEM observations show that octylsilane modification leads to efficient dispersion of Nafen in polymer matrix, while the use of alkenylsilanes leads to partial or significant aggregation of Nafen particles.

Influence of silane coupling agent on the properties of UV curable SiO2-PMMA hybrid nanocomposite

This work reports the preparation of UV-curable organic–inorganic hybrid nanocomposites synthetized by sol–gel method with the aim of obtaining highly transparent anti-abrasive coatings with long-term storage and stability for the protection of organic light emitting diodes (OLEDs). The inorganic phase is composed of tetraethoxysilane (TEOS) condensed under acid catalysis and mixed with tetrafunctionnal acrylate monomer and oligomer. Vinyltriethoxysilane (VTES), 3-methacryloxypropyltrimethoxysilane (MEMO), and 3-mercaptopropyltriethoxysilane (MTMO) are used as silane coupling agent and hybrid network modifier. Among the various parameters influencing the structure and properties of the hybrid, this work focuses on the nature and amount of coupling agent and their influence in terms of transparency, mechanical properties, and stability of the formulation. An optimum can be found in the silica to coupling agent ratio. Low level of functionalization leads to hybrids displaying poor optical performances and stability due to the coalescence of silica domains. On the contrary, an excess of functionalization reduces the abrasion resistance and the silica network formation. Changing the organic pendant of coupling agents greatly influences the properties of the coating by promoting the organic–inorganic balance. Dense and flexible as well as mechanically resistant coatings can be obtained from similar formulation by simply tuning the nature of the coupling agent depending of the needs of the application.

Cure retardation of peroxide‐cured silica filled natural rubber influenced by organosilane

The influence of silane coupling agent on properties of silica‐filled compounds under peroxide curing was investigated. bis (triethoxysilylpropyl) tetrasulfide (TESPT) was selected in this study and its content was varied from 0 to 12% w/w of silica. It is found that with increasing TESPT content, bound rubber content, tensile strength, elongation at break and tear strength are enhanced. By contrast, magnitude of Payne's effect, modulus at 100% elongation (M100) and heat build‐up are decreased. The changes of such properties are attributed to the reduction of crosslink density in conjunction with the improvements of both rubber–filler interaction and degree of filler dispersion with increasing TESPT content in the peroxide curing system. POLYM. ENG. SCI., 59:42–48, 2019. © 2018 Society of Plastics Engineers

Entrapped Styrene Butadiene Polymer Chains by Sol-Gel-Derived Silica Nanoparticles with Hierarchical Raspberry Structures.

A sol-gel transformation of liquid silica precursor to solid silica particles was carried out in a one-pot synthesis way, where a solution of styrene butadiene elastomer was present. The composites, thus produced, offered remarkable improvements of mechanical and dynamic mechanical performances compared to precipitated silica. The morphological analysis reveals that the alkoxy-based silica particles resemble a raspberry structure when the synthesis of the silica was carried out in the presence of polymer molecules and represent a much more open silica-network structure. However, in the absence of the polymer, the morphology of the silica particles is found to be different. It is envisaged that the special morphology of the in situ synthesized silica particles contributes to the superior reinforcement effects, which are associated with a strong silica-rubber interaction by rubber chains trapped inside the raspberry-like silica aggregates. Therefore, the interfaces are characterized in detail by low-field solid-state 1H NMR spectroscopy, 29Si solid-state NMR spectroscopy, and energy-dispersive X-ray spectroscopy. Low-field 1H NMR-based double-quantum experiments provide a quantitative information about the cross-link density of the silica-filled rubber composites and about the influence of silane coupling agent on the chemical cross-link density of the network and correlates well with equilibrium swelling measurements. The special microstructure of the alkoxy-based silica was found to be associated with the interaction between alkoxy-based silica and rubber chains as a consequence of particle growth in the presence of rubber chains.

Computational Thermomechanical Properties of Silica⁻Epoxy Nanocomposites by Molecular Dynamic Simulation.

Silica–epoxy nanocomposite models were established to investigate the influence of silane coupling agent on the structure and thermomechanical properties of the nanocomposites through molecular dynamics simulation. Results revealed that incorporating silica nanoparticles into a polymer matrix could improve thermomechanical properties of the composites and increase their glass transition temperature and thermal conductivity. Their thermomechanical properties were further enhanced through silane coupling agent modification on the surface of fillers. Compared with that of pure epoxy, the glass transition temperatures of the silica–epoxy composites with grafting ratios of 5% and 10% increased by 17 and 28 K, respectively. The thermal conductivities of the two models at room temperature respectively increased by 60.0% and 67.1%. At higher temperature 450 K, thermal conductivity of the nanocomposite model with a high grafting ratio of 10% demonstrated a considerable increase of approximately 50% over the pure epoxy resin (EP) model. The elastic and shear modulus of the nanocomposite models decreased at temperatures below their glass transition temperatures. These observations were further addressed in the interpretation from three aspects: segmental mobility capability, radial distribution function, and free volume fraction. Our computational results are largely consistent with existing experimental data, and our simulation model got fully validated.

Influence of Silane Coupling Agent and Nano-Filler on the Properties of Dental Resin Composite Cements

Dental resin composite cements were prepared with simply mixing method of Part A and Part B. The material components in Part A were composed of Bis-GMA, TEDGMA, 4-META, SiO2 nanopowders and BPO. The components in Part B were Bis-GMA, TEDGMA, 4-META, SiO2 nanopowders and 2,2¢-(4-methylphenylimino) diethanol. Before using SiO2 nano-filler in the formulation of Part A and Part B, it had to be coated with methacryloxypropyltrimethoxysilane (MPS) which served as a silane coupling agent. Therefore, the optimum amount of MPS (1, 1.2, 1.5 and 2%) and SiO2 nano-filler (20, 27.27 and 33.33 wt%) used to fabricate the composites were investigated. The homogeneous mixture of Part A and Part B at mass fraction of 1:1 was formed into the bar shape with dimension of 25 mm x 2.0 mm x 2.0 mm and then cured under light source for 20 s. Then flexural strength was measured using the universal testing machine. Depth of cure was tested using mould which was perforated in cylindrical shape of 6 mm in depth and of 4 mm in diameter. The result showed that composite with 27.27 wt% of salinized SiO2 nanopowders by 1.5% of MPS showed the highest flexural strength of 65 MPa and depth of cure of more than 5 mm which were accepted according to ISO 4049. This study could be concluded that using a proper amount of MPS to silanize SiO2 nanopowders and using an optimum amount of SiO2 nanopowders significantly improved the flexural strength of dental resin composite cements.

Influence of silane coupling agent on bound rubber formation of NR/SBR blend compounds reinforced with carbon black

Influence of silane coupling agent [bis-(3-(triethoxysilyl)-propyl)-tetrasulfide, TESPT] on bound rubber formation of carbon black-filled NR/SBR blend compounds was investigated. Bound rubber formation of carbon black-filled NR compounds with and without TESPT was also examined. Bound rubber contents of the NR/SBR blend compounds were less than those of the single NR compounds. Secondary layer bound rubber content of the NR/SBR compound containing TESPT was greater than that of the compound without TESPT, whereas formation of the primary layer bound rubber was not nearly affected by TESPT. For the single NR compounds, both the primary and secondary layer bound rubber contents of the compound containing TESPT were greater than those of the compound without TESPT. TESPT enhances the bound rubber formation by making sulfur crosslinks between NR chains in the compound. The secondary layer bound rubber contents of the NR/SBR blend compounds were lower than the primary layer ones, while for the single NR compounds the secondary layer bound rubber contents were greater than the primary layer ones. Rubber ratios of NR and SBR of bound rubbers of the NR/SBR blend compounds were determined using thermogravimetric analysis (TGA). The NR/SBR rubber ratio of the secondary layer bound rubber was much greater than that of the primary layer one.