Coupling Agent Loading Research Articles

Quantitative analysis of amino silane loading on copper foil using dye sensitization

A new quantification of silane coupling agent loading on the substrate based on dye sensitization principle is developed. Specifically, self-assembled monomolecular layer (SAM) formed by 3-Aminopropyl triethoxysilane (APTES) on copper foil was quantified using an acetylene-bridged anthracene sensitizer by the intermolecular interaction between the amino moiety on APTES and the carboxylic acid of the sensitizer. Compared with conventional elemental analysis to determine APTES loading, dye sensitization method not only exhibits similar accuracy but also provides valuable information regarding the effective amino moieties on the APTES-modified copper surface.

The effect of silane type on mechanical properties and fogging phenomenon of lamp socket rubber

Bis-(3-triethoxysilylpropyl) tetrasulphide (TESPT) and 3-mercaptopropyltrimethoxysilane (MTMO) were used as silane coupling agent for silica fume. The modified silica fume was used as reinforcing filler in ethylene propylene diene monomer (EPDM) for lamp socket rubber. The cure characteristics, rubber mechanical properties and fogging phenomenon of lamp socket rubber were investigated. Test results showed that the maximum torque (MH) and differential torque (MH-ML) increased but the minimum torque (ML), cure time at 10% and 90% decreased with the increasing of silane coupling agent loading. The comparison rubber mechanical properties of modified silica fume by TESPT and MTMO was also discussed. The TESPT showed the enhancement in rubber mechanical properties such as hardness, tensile strength and 300% modulus more than MTMO. The fogging test of lamp socket rubber by the gravimetric method used to control rubber products quality in automotive industry. The using of modified silica fume by TESPT showed the better result than MTMO due to less mass of condensable constituent.

Effects of coupling agent addition on the adhesive wear, frictional and thermal properties of glass fiber-reinforced polyamide 6,6 composites

In this study, effects of coupling agent addition on adhesive wear, thermal and morphological properties of glass fiber-reinforced polyamide 6,6 (PA6,6) composites were investigated. 1,4-Phenylene-bis-oxazoline (PBO) was used as coupling agent to improve the interfacial adhesion between glass fiber and PA6,6 matrix. While coupling agent loading level was changed as 0.5, 1.0 and 2.0 wt%, glass fiber loading level was fixed at 10 wt% in the composites. For tribological characterization of prepared composites, adhesive wear test was performed. Differential scanning calorimeter analysis and thermogravimetric analysis were performed for thermal characterization. In addition to this, scanning electron microscopy analysis was applied to investigate the worn surfaces and fracture surfaces of samples. Applied test results revealed that 2 wt% PBO addition improved the fiber–matrix adhesion and correspondingly adhesive wear resistance of glass fiber-reinforced PA6,6 matrix composites.

Influence of Processing Parameters on the Tensile Strength of PA-W/mLLDPE Composite Films Produced by Blown Film Extrusion

Extrusion blown films from Polyamide waste/metallocene linear low-density polyethylene (PAW/mLLDPE) blend based matrix system and calcium carbonates particles were successfully produced and characterized. Also, the effect of the extruder temperature used during twin-screw compounding, the coupling agent loading and PA loading on the mechanical properties of the obtained films were studied. The key aspect of the present study was in investigating the optimal combination of factors by using Design of Experiment (DOE) approach. The responses measured were the tensile strength in the machine direction (MD) and the tensile strength in the transverse direction (TD). Among the selected processing parameters, the coupling agent and the interaction between the coupling agent and the PA loading have the most important influence on the tensile strength.

Photocatalytic Activity and Properties of Nanotitanium Dioxide-Filled Natural Rubber in the Presence of Coupling Agents

Titanium dioxide (TiO2) is normally added into the rubber compounds as a white pigment and inorganic filler for an improvement of thermal property. TiO2 is also known to have an outstanding photocatalytic activity. This work investigates the properties of natural rubber (NR) compounds filled with 5 phr of nanoTiO2 (n-TiO2). Since the direct incorporation of n-TiO2 into NR encounters incompatibility problem, therefore two types of coupling agent (i.e. bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT) and isopropyl trioleyl titanate (ITT)) are used. The coupling agent loading is varied in a range of 0-20 wt% relative to the n-TiO2. Mooney viscosities and minimum cure torque (ML) of the compounds increase with increasing coupling agent content and the ones with ITT show higher viscosity than the mixes with TESPT. The use of TESPT leads to shorter optimum cure time and higher torque difference compared to the use of ITT. The addition of n-TiO2 results in the improved modulus, reinforcing index and tensile strength compared to the unfilled vulcanizate. The presence of both TESPT and ITT significantly reduces a photodegradation efficiency. The difference in the properties and photocatalytic activity of n-TiO2 filled NR having TESPT and ITT as coupling agent indicates their possible different level of dispersion and interactions at the interphases.

Influence of silica and coupling agent loading on thermal, morphological and mechanical properties of hybrid membranes

Hybrid polyetherimide-silica (PEI-SiO2) membranes were synthesized via the sol–gel method through the hydrolysis of tetraethoxysilane (TEOS) with 3-aminopropyltriethoxysilane (APTEOS) as a coupling agent. The effects of silica content and the APTEOS/TEOS ratio in thermal, morphological and mechanical properties of the hybrid membranes were studied. Although many studies report improvements in the structure or properties of composite materials when a coupling agent is used, these contributions do not investigate the effect of the coupling agent loading on the properties of the new material synthesized. In this study, we prepared hybrid membrane with a fixed amount of APTEOS modifying TEOS content to analyze the silica content effect. Conversely, to determine the coupling agent effect, hybrid membranes were prepared varying the APTEOS content while the amount of TEOS was kept constant. All hybrid membranes have a dense and uniform internal structure and exhibit good thermal resistance with a degradation temperature above 544 °C. Membranes with 10 wt% of silica showed better tensile strength with a high modulus and low rupture elongation indicating an effective load transfer between the phases. Concerning the coupling agent effect, the maximum modulus was observed for membranes with 10 wt% of APTEOS, suggesting a greater interaction between the organic and inorganic phases.

Effect of fiber treatment on the water absorption and mechanical properties of hemp fiber/polyethylene composites

AbstractThe hemp fiber/polyethylene (PE) composites were prepared by varying the fiber shape (hemp flour and hemp fiber from thermomechanical refining), coupling agent (maleic anhydride grafted and copolymerized onto PE), coupling agent loading method (during fiber treating process in the thermomechanical refiner and compositing process in twin screw extruder), and compositing method (twin screw extruding and batch mixing). The paper firstly measured the moisture absorption properties of the treated fibers. The introduction of coupling agent during fiber treating process decreased effectively the moisture uptake. Then, the water absorption and mechanical properties were investigated on the hemp/PE composites. The loading of coupling agent during fiber treating process decreased the water uptake but also decreased the flexural yield strength, consequently resulted in lower flexural yield strength after water exposure. The composites prepared by batch mixing method were better than by twin screw extruding for the water resistance and mechanical properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Interfacial compatibility of wood flour/polypropylene composites by stress relaxation method

AbstractTo investigate the interfacial compatibility of wood flour/polypropylene (PP) composite, compressive stress relaxation curves at different temperatures (26, 40, and 60°C) were determined at various wood contents (0, 20, 30, 40, 50, 60, and 70%) without coupling agent and further determined at wood contents of 50 and 60% by using maleic anhydride grafted polypropylene (MAPP) and silane as coupling agents. The apparent activation energy (▵E) was also calculated according to the Eyring's absolute rate reaction theory. The results showed that the stress relaxed faster at higher temperatures. ▵E of wood flour/polypropylene composites without coupling agent showed the highest value at wood content of 40%, suggesting that the best interfacial compatibility between wood and PP occurred at 40% wood content. Adding coupling agents increased ▵E obviously at higher wood contents (50 and 60%). With the increasing loading level of coupling agents, ▵E increased at first and then decreased gradually or finally reached a constant level depending on the type of coupling agent. The optimal loading of coupling agent corresponding to the highest ▵E value was related to wood content and the type of coupling agent. Within the experimental conditions used in this study, the optimal loading level for MAPP was 2% at both wood contents while for silane it was 1.5% and 2% at wood content of 50 and 60%, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Enhancement of Mechanical and Thermal Properties of Oil Palm Empty Fruit Bunch Fiber Poly(butylene adipate-co-terephtalate) Biocomposites by Matrix Esterification Using Succinic Anhydride

In this work, the oil palm empty fruit bunch (EFB) fiber was used as a source of lignocellulosic filler to fabricate a novel type of cost effective biodegradable composite, based on the aliphatic aromatic co-polyester poly(butylene adipate-co-terephtalate) PBAT (EcoflexTM), as a fully biodegradable thermoplastic polymer matrix. The aim of this research was to improve the new biocomposites’ performance by chemical modification using succinic anhydride (SAH) as a coupling agent in the presence and absence of dicumyl peroxide (DCP) and benzoyl peroxide (BPO) as initiators. For the composite preparation, several blends were prepared with varying ratios of filler and matrix using the melt blending technique. The composites were prepared at various fiber contents of 10, 20, 30, 40 and 50 (wt %) and characterized. The effects of fiber loading and coupling agent loading on the thermal properties of biodegradable polymer composites were evaluated using thermal gravimetric analysis (TGA). Scanning Electron Microscopy (SEM) was used for morphological studies. The chemical structure of the new biocomposites was also analyzed using the Fourier Transform Infrared (FTIR) spectroscopy technique. The PBAT biocomposite reinforced with 40 (wt %) of EFB fiber showed the best mechanical properties compared to the other PBAT/EFB fiber biocomposites. Biocomposite treatment with 4 (wt %) succinic anhydride (SAH) and 1 (wt %) dicumyl peroxide (DCP) improved both tensile and flexural strength as well as tensile and flexural modulus. The FTIR analyses proved the mechanical test results by presenting the evidence of successful esterification using SAH/DCP in the biocomposites’ spectra. The SEM micrograph of the tensile fractured surfaces showed the improvement of fiber-matrix adhesion after using SAH. The TGA results showed that chemical modification using SAH/DCP improved the thermal stability of the PBAT/EFB biocomposite.

Dynamic mechanical properties and hysteresis loss of epoxidized natural rubber chemically bonded to the silica surface

AbstractHigh‐temperature (180°C) molding of epoxidized natural rubber (ENR) filled with precipitated silica leads to chemical bond formation between epoxy groups of ENR and silanol groups of silica. The extent of chemical bond formation is further enhanced in the presence of the silane coupling agent N‐3‐N‐(vinyl benzyl amino)ethyl‐γ‐amino‐propyl trimethoxy silane mono hydrogen chloride (trade name Z‐6032). The results of hysteresis loss measurements show that hysteresis loss increases with increase in coupling agent loading as a result of the higher modulus of the compounds compared to that of the ENR–silica mix. The dynamic mechanical property measurements show that the addition of coupling agent increases the glass‐transition temperature. Whereas strain‐dependent dynamic mechanical properties show that filler structure breakdown increases with increasing loading of coupling agent. Sulfur‐cured systems show higher filler structure breakdown compared to that of nonsulfur systems. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2171–2177, 2002