Effect Of Coupling Agent Research Articles

Molecular Simulation of Improved Mechanical Properties and Thermal Stability of Insulation Paper Cellulose by Modification with Silane-Coupling-Agent-Grafted Nano-SiO2

Cellulose is an important part of transformer insulation paper. Thermal aging of cellulose occurs in long-term operation of transformers, which deteriorates the mechanical properties and thermal stability of cellulose, resulting in a decrease in the transformer life. Therefore, improvement of the mechanical properties and thermal stability of cellulose has become a research hotspot. In this study, the effects of different silane coupling agents on the mechanical properties and thermal stability of modified cellulose were studied. The simulation results showed that the mechanical parameters of cellulose are only slightly improved by KH560 (γ-glycidyl ether oxypropyl trimethoxysilane) and KH570 (γ-methylacrylloxy propyl trimethoxy silane) modified nano-SiO2, while the mechanical parameters of cellulose are greatly improved by KH550 (γ-aminopropyl triethoxy silane) and KH792 (N-(2-aminoethyl)-3-amino propyl trimethoxy silane) modified nano-SiO2. The glass-transition temperature of the composite model is 24 K higher than that of the unmodified model. The mechanism of the change of the glass-transition temperature was analyzed from the point of view of free-volume theory. The main reason for the change of the glass-transition temperature is that the free volume abruptly changes, which increases the space for movement of the cellulose chain and accelerates the whole movement of the molecular chain. Therefore, modifying cellulose with KH792-modified nano-SiO2 can significantly enhance the thermal stability of cellulose.

Effect of Silane Coupling Agent on the Properties of Recycled Carbon Fibers Reinforced Bio-based Epoxy Composites

In this work, the effect of a silane coupling agent on the mechanical behavior of recycled carbon fiber reinforced bio-based epoxy composites was studied. For this purpose, the surface of the recycled carbon fiber was treated with 3-aminopropyltriethoxysilane (APS) agent at the concentrations in the 0–8 wt.% range. Dynamic mechanical analysis and characterization of the tensile and flexural properties were performed to observe the mechanical behavior of the specimens, and the morphology of the fracture surface after mechanical testing was also studied by scanning electron microscopy. It was found that the glass transition temperature and the tensile and flexural strengths of the composites increased with an addition of a suitable amount of the silane agent (< 4 wt.%), which was attributed to the cross-linking and curing reaction between the amino groups of APS and the epoxy matrix that improved the interfacial bonding. Thus, an appropriate concentration of the silane coupling agent can improve the mechanical properties of recycled carbon fiber reinforced bio-based epoxy composites.

Effect of fly ash and coupling agent on the structural, morphological, thermal, and mechanical properties of polyamide 6/acrylonitrile‐butadiene‐styrene blend

AbstractIn the present study, coal fly ash (FA) was used as a reinforcement in a thermoplastic matrix blend of polyamide 6/acrylonitrile‐butadiene‐styrene (PA/ABS). In the first part of this work, the as‐received FA (raw FA) was sieved with a 25 μm sieve to obtain FA with particle size less than 25 μm (FA). Then, the physicochemical properties of the raw FA and the FA were determined. Afterwards, FA was used to prepare a masterbatch of 20 wt% FA and 80 wt% PA by twin‐screw extrusion. Using this masterbatch, composites with different FA contents (4.5, 9, 14, and 18.5 wt%), with and without styrene‐(ethylene‐butylene)‐styrene grafted with maleic anhydride (SEBS‐g‐MA) (S‐g‐M), were produced by extrusion, which was followed by injection molding. Subsequently, several characterization techniques were performed to investigate the effect of FA loading and the S‐g‐M coupling agent on the structural, morphological, thermal, and mechanical properties of the developed composites. The results showed that incorporating FA particles in the matrix blend improved the thermal stability and crystallinity, the Young's modulus, the tensile strength, and torsional properties of the composites. In contrast, the addition of S‐g‐M coupling agent to the polymer composites improved the interfacial adhesion between FA particles and the matrix blend. This further enhanced the structural, morphological, thermal, and mechanical properties of the polymer composites. Overall, the use of FA as an inorganic filler improves the thermal and mechanical properties of polymer composites and shows a potential for promising applications.

Effect of silane coupling agent on the mechanical steel of sugarcane baggase and polypropylene composites

A composite material is produced by combining two or more materials to give a specific combination of properties, one consisting of rigid, long fibres and the other a binder or ‘matrix’ holding the fibres in place. Compared to the matrix, the fibres are strong and stiff, typically orthotropic. More recently, natural fibres were used in plastics. The broad availability of natural fibre in India, such as Jute, Coir, Sisal, Pineapple, Ramie, Bamboo, Banana, etc., pays specific attention to the manufacture of natural fibre composites to pursue value-added applications. This natural fibre composites are well suited to substitute wood in homes and manufacturing. Natural fibre reinforcement in composites has recently drawn ads due to low cost, low density, fair basic features, fast separation, improved energy recovery, CO2 neutrality, biodegradability and recyclability. Thousands of tonnes of different crops are made, but most of their waste is useless. It contains wheat husk, rice husk and grass, hemp fibre and dried fruit shells. These agricultural waste may be used for fibre-reinforced polymer composites for commercial usage. This project explores the impact of the silane binding agent on the mechanical properties of the sugar cane baggase and polypropylene compounds. Coupling agent is the agent used to strengthen the connection between the reinforcement and the matrix. In this plant, silane was used as a binding agent for sugar cane bagasse bio-composites. Reinforcement content treated with a binding agent at varying concentrations of 0 per cent, 10 per cent, and 20 per cent. This element was present in the compression moulding method for the manufacture of composite boards. The influence of the silane binding agent on the mechanical properties of the composites, such as the tensile, flexural and impact forces, was evaluated.

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.

Recent Progress in Silane Coupling Agent with Its Emerging Applications

This paper presents the effects of silane coupling agent, which includes interfacial adhesive strength, water treatment, polymer composites and coatings that make it valuable for multi-materialization. The methoxy-type silane coupling agent composites-based modification is discussed using different methods exhibiting higher reactivity towards hydrolysis. The characteristics of developed vulcanization, in particular the dimethoxy-type silane-coupling agents than the trimethoxy-type have improved properties such as environment friendly fabrication process, mechanical, physical, swelling and dynamic viscoelastic properties of composites. The modification of aggregated surface along with asphalt binder excel their properties. Specifically, the silane coupling agent (SCA) Glycidoxypropyl trimethoxysilane (KH-560) utilization realizes the modification purpose. This review focuses on synthetic approaches, surface modification, surface thermodynamic properties, techniques, salinization reaction and recent development in use of silane modifiers in various applications.

Effect of Silane Coupling Agent on Flexural Strength and Hardness of Wheat Straw Polystyrene Composites

In the present research work, the effect of silane treatment along with alkali treatment on flexural strength, flexural modulus, and hardness investigated. Wheat straw as a filler was added (5%, 10%, 15% and 20%) to polystyrene matrix to prepare wheat straw polystyrene composite. The wheat straw fibre was first treated with 20% NaOH and 1% silane coupling agent to prepare wheat straw polystyrene composite. The compounding process was carried out in twin-screw extruder and samples were prepared by the compression moulding process. There was an increase in flexural modulus (214%), flexural strength (44%), and hardness (28%) of composite with the addition of alkali and silane treated wheat straw fibre.

Effect of Alkaline Treatment and Coupling Agent on Thermal and Mechanical Properties of Macadamia Nutshell Residues Based PP Composites

The influence of alkaline treatment on the thermal and mechanical properties of polypropylene (PP) reinforced with fibers from macadamia nutshell (5 to 30 wt%) was studied. To improve the interaction between fiber and matrix, the fibers were submitted to an alkaline treatment, as well as a coupling agent (MAPP) was used. The composites were obtained in a thermokinetic mixer, milled, and injected. Then, the degradation temperature and the loss of mass of the composites, pure PP, and fibers were evaluated. The mechanical properties of the composites were also evaluated. The results indicated that the degradation peak of composites occurred at higher temperatures, which indicated that composite exhibited higher thermal stability at higher temperatures. The addition of raw and treated macadamia fibers to the PP increased the stiffness of the composites, as well as the use of a coupling agent when compared to the neat PP. However, the incorporation of 30 wt% treated fiber to the PP showed an enhancement of 67.5% in the tensile modulus. The morphological analysis enabled to evaluate the efficiency of the coupling agent and the treated fibers adhered to matrix. The response surface methodology (RSM) technique showed that the higher fiber content added to the PP enhanced the stiffness, and consequently reduced the impact strength of the materials.

Effect of different coupling agents on the interfacial properties of tube–internally insulated foam materials interface in a composite cross‐arm under water environment

Effect of different coupling agents on the interfacial properties of tube–internally insulated foam materials interface in a composite cross‐arm under water environment

Effect of Silane Coupling Agents on Cotton Fibre Finishing

ABSTRACT Five different silane coupling agents such as vinyltrimethoxysilane (VTMS), vinyltriethoxysilane (VTES), trimethoxysilylpropylmethacrylate (TSPM), glycidoxypropyltriethoxysilane (GPTES) and aminopropyltriethoxysilane (APTES) were used for the surface finishing of cotton fiber by condensation polymerization in ethanol/water medium. The finished cotton fiber showed improved textile properties like tensile strength, wear comfortness, moisture absorption and wrinkle recovery, but decreased swelling in aqueous solution. The finished cotton fibers were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Energy Dispersive X-ray (EDX), thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG). Attachment of silane coupling agents was confirmed and the finished cotton fiber showed increased thermal stability than the unfinished cotton. The finished cotton fiber showed higher reactive dye exhaustion due to silane coupling agent imparts new reactive sites for dye molecule on cotton fiber. The finished cotton fiber showed excellent fastness properties like washing, sunlight and chemical fastness properties. Improved textile properties of the silane finished cotton fiber with higher flexibility due to the presence of Si-O bond between the silane coupling agents and the cotton fiber, causes increased wear comfortness. Possible applications include use of the finished fibers as textile materials and garments.

Interface Strength and Fiber Content Influence on Corn Stover Fibers Reinforced Bio-Polyethylene Composites Stiffness.

Stiffness of material is a key parameter that allows the use of material for structural or semi-structural purposes. Besides, lightweight materials are increasingly calling the attention of the industry. Environmental impact is also increasing in its importance. Bio-based materials produced from renewable sources can be good candidates for structural purposes combining lightweight and low environmental impact. Nonetheless, similar mechanical properties of commodities have to be reached with such materials. In this work, composite materials from corn stover fibers as a bio-polyethylene reinforcement were produced and tested. The effect of coupling agents to improve the fiber–matrix interface has been evaluated. It has been found that coupling agent content influenced the stiffness of the materials, increasing the Young’s modulus and the material processability. The best performance was achieved for a 6% of coupling agent, corresponding to 4.61 GPa for 50 w/w% of corn stover fibers. Micromechanics showed the impact of the semi-random orientation of the fibers and the lesser impact of its morphology. It was possible to determine a triangular packing of the composites as a hypothesis for future research.

Electrical Properties of Bamboo Fiber Reinforced Polypropylene Composite: Effect of Coupling Agent

ABSTRACT Electrical properties of blends from Polypropylene (PP) and bamboo fiber have been studied at various amounts of fiber compositions. Blending of bamboo with nonpolar polymer such as PP is expected to improve the dielectric performance of bamboo fiber by reducing the polarity. This paper presents the results of dielectric properties of bamboo fiber-reinforced PP composites. Special attention has been paid to analyze the influence of coupling agent (Maleic Anhydride Polypropylene) on the dielectric properties of the resulting composites. The temperature dependence of dielectric properties on the composites has also been studied. Capacitance (C), dielectric loss or tan δ (D), Impedance (Z) and conductivity (G) with frequency were measured at different temperatures. Polypropylene has a major role on environmental pollution as it is not biodegradable. So, this study aims to use such polymers to be incorporated with bamboo fiber to achieve high dielectric constant with low loss in polymer composites for embedded capacitor applications. Polypropylene is used as a host matrix due to its higher mechanical strength and ease of processing at low temperature.

Effect of Different Coupling Agents on Interfacial Properties of Fibre-Reinforced Aluminum Laminates.

Metal composite interface properties significantly affect the integrity, bonding properties, and interface structure of Fibre Metal Laminates (FMLs). Interfacial bonding strength’s effect on Carbon Fibre-Reinforced Aluminium Laminate (CARALL) mechanical behaviours was investigated via three-point bending and low-velocity impact tests. AA6061 sheets were subjected to surface pretreatments under three conditions (anodizing and A-187 and A-1387 surface modifications) to obtain different interfacial bonding strengths. The bonding interfaces of CARALL were analysed using scanning electron microscopy, energy dispersive spectroscopy and X-ray photoelectron spectroscopy. Interfacial bonding strength between aluminium alloy and epoxy resin was determined by the tension-shear test. CARALL’s energy absorption capacity and failure mode were analysed after low-velocity impact and three-point bending under different aluminium alloy volume contents and surface pretreatments. Upon modification of metal surfaces, the interfacial bonding strength increased, and the highest was obtained by silane coupling agent A-1387. Improved strength maintained FML’s integrity under quasi-static and dynamic loadings. A-1387 improved the bonding ability of aluminium alloy and Carbon Fibre-Reinforced Plastics (CFRP). The composite interface strongly resisted crack propagation because of its functional group characteristics. When the volume content of aluminium alloy was less and greater than that of CFRP, the energy absorption capacity of CARALL weakened and strengthened, respectively, with increasing interfacial bonding strength.

Construction of compatible interface of straw/magnesium oxychloride lightweight composites by coupling agents

To solve the problem of agricultural waste, modified straw/magnesium oxychloride lightweight composites (M−SMOCL) with light-weight and high strength were prepared using magnesium oxychloride cementitious material (MOC) as the matrix, modified straw as reinforcing material and other reagents as additives. The effects of coupling agents, including KH-550, KH-560, KBM-603, HY-201, on straw groups and water absorption, as well as the mechanical strength and water resistance of the composites, were examined and discussed. The results showed that coupling agents reduced straw hydrophilicity and water absorption, improved composite performance. KBM-603 in particular possessed the best modification effects, with water absorption of straw treated with KBM-603 decreased to 27%, and the composite compressive and bending strengths of reached the maximum values of 12.93 MPa and 4.78 MPa, respectively. FT-IR and SEM showed that straw treated with KBM-603 bonded more closely to the matrix, creating the best interface results.

Epoxidised sesame oil as a biobased coupling agent and plasticiser in polylactic acid/thermoplastic yam starch blends

This work aims to improve the physicochemical properties of polylactic acid (PLA) and thermoplastic yam starch (TPS) blends using epoxidised sesame oil (ESO). We used epoxidised sesame oil from two Colombian Caribbean crops: Dioscorea rotundata and Sesamum indicum, with an oil substitution of 58.4 %. Films were obtained through extrusion and compression moulding processes. Moisture content, solubility, contact angle, and mechanical, barrier, and structural properties were determined using optical and scanning electron microscopy, infrared Fourier transform spectroscopy. Thermal analyses were also performed using thermogravimetry and differential scanning calorimetry techniques. The results suggest that the PLA and TPS interactions can be improved with the addition of ESO as coupling agent, enhancing the interfacial adhesion between the polymers, and favouring the smoothness of the film surface. Furthermore, the ESO addition led to increased thermal stability while restricting molecular mobility, indicating a coupling agent effect. In conclusion, the use of epoxidised oil for preparing films based on high PLA content and TPS allows obtaining enhanced interfacial adhesion. Considering the above, the developed materials have potential application in semi-rigid food packaging.

Synthesis, characterization, photophysical properties, and computational studies onN-hexylphenothiazine/cyanopyridine based π-conjugated copolymers

In this paper, π-conjugated copolymers, namely N-hexylphenothiazine/cyanopyridine/phenyl/benzothiadiazole, N-hexylphenothiazine/cyanopyridine/phenyl/9,9-dihexylfluorene, and N-hexylphenothiazine/cyanopyridine/phenyl/9,9-diethylhexylfluorene were readily synthesized via Pd-catalyzed Suzuki cross-coupling reaction. The polymer structures and their photophysical properties were characterized by elemental analysis,1H NMR, GPC, TGA, XRD, UV-vis absorption and PL spectroscopy measurements. The coupling agent effect on photophysical properties of copolymers was investigated to rationally design polymers with particular physical properties to be employed in optoelectronic devices. The UV-vis absorption spectroscopy of copolymers showed λmaxat a range of ∼334–474 nm and red-shifted in their films to a range of ∼342–381 nm. These copolymers displayed highly intense fluorescence in their solutions and films. The PL spectra of copolymers indicated red and near-infrared light, rendering them a prospect for being red and near-infrared light-emitting materials for PLEDs. XRD analysis demonstrated a d-spacing range of ∼3.79–4.32 Å, reflecting π-π stacking and some degree of crystallinity in some polymers, and only P1 and P2 showed peaks in the small-angle region, indicating lamellar structures. To understand the relationship between molecular structures of target materials and their photophysical and photovoltaic properties, density functional theory (DFT) and its time-dependent form (TD-DFT) were employed.

Effect of surface coupling agents on the mechanical behaviour of polypropylene/silica composites: a molecular dynamics study

We investigate the mechanical behavior of polypropylene/silica composites under mode I and II loading by using molecular dynamics simulations, focusing on the effects of two typical surface coupling agents of HMDZ and APTES on the interface deformation and failure. It is found that under mode I loading, the silica surface functionalized with APTES can enhance the tensile strength of polypropylene/silica composites effectively. In contrast, the silica surface functionalized with HMDZ has little effect on the tensile strength. The simulation results are supported by experiments. Under mode II loading, it is found that both HMDZ and APTES can enhance the shear strength of polypropylene/silica composites with APTES being more effective. The underlying mechanisms for the enhancement of interface strength are analyzed. Our work provides a deep understanding of the interface structure, deformation and failure and will be useful for selecting suitable surface coupling agents in enhancing the interface strength of polymer composites.

Effect of coupling agent and alkali treatment on mechanical, thermal and morphological properties of flax-fiber-reinforced PLA composites

In the current study, three different types of biocomposites based on poly(lactic acid) (PLA) and short flax fiber were produced using extrusion. Alkali treatment was conducted on the flax fiber before the extrusion process in order to improve the interfacial adhesion between the flax fiber and the PLA matrix. The influence of the coupling agent and alkali treatment on the composite materials was investigated with regard to the mechanical, thermal and thermomechanical properties of the injected composites. The results show that the coupling agent has a favorable effect on the thermal, thermomechanical and mechanical properties of the composites. The flexural and tensile moduli of the composites were significantly enhanced compared with those of pure PLA samples. Dynamic mechanical thermal analysis and thermogravimetric analysis (TGA) results indicate that the loss and storage modulus of PLA/flax fiber composites are increased compared with those of both pure PLA and composites with the coupling agent. The TGA showed that the thermal stability of PLA improved with the addition of flax fiber into PLA. Additionally, the developed flax fiber content in PLA with the coupling agent improved the tensile, flexural strength and flexural modulus. The tensile strength of the alkali-treated flax fiber increased up to 50 MPa compared with that of the untreated flax fiber. The Fourier transform infrared spectroscopy method was carried out to examine the chemical composition of the composite and interaction of functional groups for both alkali-treated and untreated flax fibers.

Effect of Silane Coupling Agent on Modification of Areca Fiber/Natural Latex.

In this paper, the areca fiber was extracted by physical and chemical treatment, and then the areca fiber/natural latex composite was prepared by natural latex impregnation technology. In order to combine areca fiber and natural rubber latex better, three silane coupling agents with different action mechanism were selected: Si−69, KH550, and KH570 which were used to treat the areca fiber/natural latex compound. The results show that the silane coupling agent can change the surface of the fiber from hydrophilic surface to organophilic surface, making the bonding of areca fiber to natural latex more closely. At the same time, the mechanical properties, physical and mechanical properties, swelling properties, and dynamic viscoelastic properties of the tightly bonded areca fiber/nature latex composites were improved. After observing the micro-structure through a scanning electron microscope, it was found that the three silane coupling agents could effectively bind areca fiber and natural latex to enhance the performance of the composite material, of which Si−69 performed best, and the tensile strength and tear strength of the composite increased by 21.19% and 12.90% respectively.

Effect of Nanosilica and Crosslinking System on the Mechanical Properties and Swelling Resistance of EPDM/SBR Nanocomposites with and without TESPT

The ethylene-propylene-diene monomer/styrene-butadiene rubber (EPDM/SBR)-nanosilica (SiO2) nanocomposite was prepared. The 0–10 parts per hundred rubber (phr) of SiO2 with EPDM/SBR was mixed on a two-roll mill. The effect of nanosilica (0–10 phr), crosslinking system (sulphur, dicumyl peroxide and mixed) and silane coupling agent (bis(triethoxysilylpropyl)-tetrasulphide) on the curing characteristics, mechanical properties, rebound resilience, compression characteristics, abrasion, swelling property and morphological characteristics of the EPDM/SBR-SiO2 nanocomposites was investigated and studied. From the results, it was clear that the mechanical, wear and swelling properties steps-up with increase in the content of nanosilica particles in it. The sulphur cured rubber composite exhibits an overall improved properties as compared with other crosslinking agents such as peroxide and mixed systems. The addition of silane coupling agent (SCA) enhances the properties of the nanocomposites to a greater extent. From the analysis, it was clear that the effect of nanosilica concentration in the rubber composite with SCA was found to be superior compared to nanocomposites without it.