Types Of Coupling Agents Research Articles

Effect of treated mica on rheological, cure, mechanical, and dielectric properties of ethylene propylene diene monomer (EPDM)/barium titanate (BaTiO3)/mica

ABSTRACTIn this study, mica, treated by three types of coupling agents, isopropyl trioleic titanate (NDZ105), 3‐aminopropyltriethoxysilane (KH550), and vinyltrimethoxysiloxane homopolymer (SG‐Si6490), were utilized to improve the properties of ethylene propylene diene monomer (EPDM)/barium titanate (BaTiO3) composites. It is found that the addition of untreated mica can increase the complex viscosity, while the KH550 modified mica can reduce the complex viscosity. Compared to single usage of coupling agent SG‐Si6490, the hybrid usage of KH550 and SG‐Si6490 can further increase the tensile strength of EPDM/BaTiO3/SG‐Si6490 treated mica (70/20/10) from 9.10 to 11.01 MPa (22% increase). The untreated mica can increase the interfacial polarity and improve the dielectric constant of EPDM/BaTiO3 (70/30) from 7 to 9 at 40 MHz (28% increase). Moreover, the KH550 treated mica can enhance the thermal conductivity of EPDM/BaTiO3 (70/30) from 0.323 W m−1 K−1 to 0.446 W m−1 K−1 (38% increase). In the meantime, the increased crosslink density caused by coupling agents can increase the volume resistivity of EPDM composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44833.

Effect of different silane coupling agents on cryogenic properties of silica-reinforced epoxy composites

Epoxy-based composites containing silica modified by various silane coupling agents (SCAs) were prepared. The effect of the SCAs and the silica content on the thermal, mechanical properties, and fracture toughness of the nanocomposites was investigated. The particle size and dispersion state of the modified silica particles in the matrix were determined by transmission electron microscopy. The modification of silica with SCAs was verified by Fourier transform infrared spectroscopy. The specific tensile properties at ambient temperature (AT, 298 K) were compared with those at cryogenic (LT, 77 K) condition for silica content of 1−5 wt%. The effect of certain types of coupling agents on the thermal properties of the composites was also investigated. The Tg of all amino-silane-modified composites tended to be improved at low silica contents, while that of epoxy-silane-modified composites seemed to be enhanced further at high silica content. The tensile properties of the nanocomposites both at AT and LT tended to be enhanced at lower silica content, especially the failure strain. The fracture toughness ( KIC) turned out to be better enhanced by coupling agents at LT. The difference of the toughening mechanism at AT and LT was examined according to the morphology of the fracture surfaces using the scanning electron microscopy.

Influence of Different Coupling Agent Type on Processibility and Applicability of Polymer Composites

The contribution deals with the processibility and applicability of polymer composite systems based on polypropylene matrix. The composites were filled with vegetable fibres (particularly the cotton fibres, coir fibres, hemp fibres and jute fibres) and the interface between the polymeric matrix and the natural fibres was modified using two types of coupling agents (the organosilane coupling agent and maleic anhydride grafted polypropylene). For evaluation of the final impact of all three phases presence on the processibility of the polymer composite the melt flow behaviour was analyzed (MFI analysis according to ISO 1133) for the filler concentration of 10, 20 and 30 wt. %. This study involves also the natural fibre surface profile analyses (based on SEM observation) and the applicability of created composite materials was determined using the heat deflection temperature (HDT analysis according to ISO 75).

Comparison of rheological, mechanical, electrical properties of HDPE filled with BaTiO3 with different polar surface tension

In this work, three types of coupling agents: isopropyl trioleic titanate (NDZ105), vinyltriethoxysilane (SG-Si151), 3-aminopropyltriethoxysilane (KH550) were applied to modify the surface tension of Barium titanate (BaTiO3) particles. The Fourier transform infrared (FT-IR) spectra confirm the chemical adherence of coupling agents to the particle surface. The long hydrocarbon chains in NDZ105 can cover the particle surface and reduce the polar surface tension of BaTiO3 from 37.53mJ/m2 to 7.51mJ/m2, turning it from hydrophilic to oleophilic properties. The short and non-polar vinyl groups in SG-Si151 does not influence the surface tension of BaTiO3, but make BaTiO3 have both hydrophilic and oleophilic properties. The polar amino in KH550 can keep BaTiO3 still with hydrophilic properties. It is found that SG-Si151 modified BaTiO3 has the lowest interaction with HDPE matrix, lowering the storage modulus of HDPE composites to the greatest extent. As for mechanical properties, the polar amino groups in KH550 on BaTiO3 surface can improve the adhesion of BaTiO3 with HDPE matrix, which increases the elongation at break of HDPE composites to the greatest extent. In terms of electrical properties, the polar amino groups on surface of BaTiO3 can boost the dielectric properties of HDPE/BaTiO3 composites and decrease the volume resistivity of HDPE/BaTiO3 composites. The aim of this study is to investigate how functional groups affect the rheological, mechanical and electrical properties of HDPE composites and to select a coupling agent to produce HDPE/BaTiO3 composites with low dielectric loss, high dielectric constant and elongation at break.

Waste ceramic dust activated by gamma radiation and coupling agents as reinforcement for nitrile rubber

The effect of silicate load in waste ceramic dust on characteristics and performance of acrylonitrile butadiene rubber has been investigated. In order to enhance the interfacial adhesion between the rubber matrix and the filler, the latter was activated with two different types of coupling agents, vinyltriethoxysilane (SN) and maleic anhydride (MA), and then subjected to gamma rays at 100 kGy. Scanning electron microscopy, Fourier‐transform infrared spectroscopy, and X‐ray diffraction techniques were implemented to feature how the unmodified and modified waste ceramic dust were affected by the coupling agents. The effect of filler incorporation ratio on the physicomechanical and thermal properties of the rubber was studied. Mechanical properties, namely tensile strength, elongation at break, elastic modulus, and hardness, showed increases with both coupling agents. J. VINYL ADDIT. TECHNOL., 24:37–43, 2018. © 2015 Society of Plastics Engineers

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.

The Effects of Coupling Agent on the Flame Retardant Properties of PP/ATH Nanocomposites

It is known that polymeric materials are easily to get on fire due to their chemical structures. Thus the flame retardant material such as aluminium hydroxide (ATH) is used to improve the flame retardancy property of polymers. Polypropylene (PP) with various amount of nanosized ATH particles of (5, 10, 20, 30, 40 wt%) were compounded with an extruder machine. The effects of two different type of coupling agent (3-Aminopropyltriethoxysilane (APS) and Maleic anhydride grafted polypropylene (MAPP)) on the flame retardant properties were compared. All samples were characterized with two flame tests; the limiting oxygen index (LOI) and UL94 horizontal burning test (UL94 HB). It is found that both tests showed improvement on the flame resistance properties of the nanocomposites, mainly at high ATH loadings. Type of coupling agents affects the flame retardancy properties of PP/ATH nanocomposites.

Effect of coupling agent on nano-ZnO modification and antibacterial activity of ZnO/HDPE nanocomposite films

Commercial zinc oxide nanoparticles were modified by silane coupling agent of KH550 and KH560, respectively. The obtained nanocomposite was characterized by scanning electron microscopy (SEM), Thermogravimetric analyses (TGA) and apparent sedimentation stability (Sapp). Then, nano-ZnO/high-density polyethylene (HDPE) composite films were prepared via melt blending and a hot compression-molding process. The antibacterial testing of the films against E. coli and S. aureus was carried out via plate counting. SEM, TGA and Sapp suggest the modifier of silane changed the surface hydrophilicity and effectively broke the agglomerations of nanoparticles. Antibacterial testing results indicated the antibacterial rate of the films increased with increasing nano-ZnO content. At a low doped content of 0.2 wt%, the types of coupling agent influenced the antibacterial property with that of KH560-modified nano-ZnO/HDPE KH550-modified nano-ZnO/HDPE unmodified nano-ZnO/HDPE films. When the dosage nano-ZnO was over 0.2 wt%, the differences of antibacterial activity resulted by modification was concealed by the strong antibacterial activity with near 100% of the nano- ZnO/HDPE composite films.

Improved synthesis of bicyclic polystyrenes by ATRP and “click” reaction

A series of bicyclic polystyrenes were prepared by combining atom transfer radical polymerization and click coupling reaction. To investigate effect of experimental parameters, bicyclic polymers were prepared by changing types of ligands for click chemistry, concentration of polymers and coupling agents, feed rate of polymers and coupling agents, concentration of catalyst, and types of coupling agents. Purities of bicyclic polymers were estimated from SEC traces by Gaussian multiple peak fitting and subsequent peak integration. The purity of bicyclic polystyrene was achieved up to 78% when the reaction was conducted using CuBr/PMDETA catalyst and coupling agent having electron withdrawing group in diluted condition by slow addition of precursor polymer and coupling agent.

Investigation on Mechanical Properties of Occ Fiber-Hdpe Composite Containing Different Types of Coupling Agents

In this study, the effects of adding different coupling agents, e.g. maleic anhydride-grafted polyethylene (MAPE), silane (3-aminopropyltrimethoxy silane) (silane 1189) and isocyanate (hexamethylenediisocyanate) (HDI) on mechanical and morphological properties of composite samples of high density polyethylene/old corrugated container fibres (HDPE/OCC) were studied. The amounts of OCC fibre and coupling agents used were 30% and 2% of dry composite weight, respectively. Mixing of materials was carried out by a two-screw counter extruder and samples were prepared by injection moulding. In order to compare the results of the use of mixture coupling agents, their effects were studied independently, as well. Mechanical properties of prepared composite samples containing coupling agents were measured and the results were compared with those of pure high density polyethylene and those of composite samples without coupling agent. The measured mechanical properties showed that maximum values of tensile and flexural strengths and tensile and flexural modulus could only be obtained in composites containing a mixture of silane1189 and MAPE coupling agents. It was also observed that the Izod impact strength values of composites with coupling agents increased significantly. SEM micrographs of failure surfaces of samples showed that the best homogeneity of composites and bonding between OCC fibres and polymer matrix were obtained for the sample containing 1 wt.% silane and 1 wt.% MAPE.

A novel route for injection moulding of long carbon fibre-reinforced LLDPE

The scope of our work has been the development of a new type of coupling agent by which processing of long carbon fibre-reinforced thermoplastic composites by conventional injection moulding can be possible. The experimental additive was expected to hinder fibre breakage and to simultaneously improve the mechanical properties of the composites. Resistance of LLDPE reinforced with 1–10 wt% long carbon fibres against tensile, flexure and impact stresses has been investigated. Tensile strength of carbon fibre/LLDPE composites has increased by 10–30%; flexure strength has gained 15–90% related to the neat polymer depending on the fibre concentration. The effect of a blowing agent on the mechanical properties has also been investigated. At least 20% higher yield strength has been measured for the foamed sample with 5% carbon fibre related to the nonfoamed one with the same fibre content. The higher the fibre content was, the higher the improvements in the mechanical properties became. Fibre–matrix interaction has been studied on scanning electron microscopy graphs where a well-connected polymer layer has been observed to the fibre surface.

Characterization of ultrasound-treated oil palm empty fruit bunch-glass fiber-recycled polypropylene hybrid composites

Abstract Glass fiber (GF) and ultrasound-treated oil palm empty fruit bunch (EFB) were used to prepare recycled polypropylene (RPP)-based hybrid composites through the extrusion and injection molding technique. The ultrasound technique was used to remove the lignin and other surface impurities from the EFB fiber by varying the treatment conditions (treatment time and temperature). A fixed concentration (10%) of NaOH solution was used as the treatment medium. Fiber loading was considered as 40%, while EFB and GF ratio was maintained as 70:30. Two types of coupling agents of maleic anhydride grafted PP (MAPP), Polybond and Fusabond, were used, each of an amount 2.5% (of the total fiber content), to improve the interfacial adhesion between fibers and matrix. Composites were characterized through density, melt flow index (MFI), tensile, flexural and Izod impact testing. In addition, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were also performed to evaluate the thermal and morphological properties, respectively. X-ray diffraction (XRD) analysis was performed to evaluate the crystalline structure of the samples. Finally, water uptake (WU) measurement was performed for 180 days of soaking period. Result analyses revealed improved mechanical, thermal and crystalline properties, with reduced WU as the outcome of treatment and coupling agent effects.

Ultrasound assisted diazotization and diazo coupling reactions using trichlorotriazine

A high rate and efficient procedure for the synthesis of azo dyes has been developed. This concluded the sequential diazotization-diazo condensation of aromatic amines such as 4,4′-sulfonyldianiline with NaNO2, or trichlorotriazine with coupling agents under ultrasound irradiation at room temperature. This method applied to several types of coupling agents led to corresponding azo dyes in high yield within short reaction time. The mild reaction conditions and inexpensive procedure are clear advantages of this method.

Characterization of oil palm empty fruit bunch and glass fibre reinforced recycled polypropylene hybrid composites

The effects of hybridization of glass fibre on oil palm empty fruit bunch (EFB) and recycled polypropylene-based composites are described in this paper. The compounding process involved extrusion followed by injection moulding technique to prepare the samples for characterizations. Fibre loading were considered as 40 % of the total weight of the blends and EFB:glass fibre ratio was maintained as 30:70, 50:50, 70:30 and 90:10. Two types of coupling agents of maleic anhydride-grafted polypropylene such as polybond-3200 and fusabond P-613 of different molecular weight and maleic anhydride level were used to improve the interfacial adhesion between the fibres and the matrix. Composites were characterized by density, melt flow index, tensile, Izod impact and flexural testing. Morphological images of the fractured surfaces of the composites were examined by field-emission scanning electron microscopy. Samples were also characterized by thermal tests such as thermogravimetric analysis and differential scanning calorimetry to evaluate the thermal and crystalline properties, respectively. Optimization of hybridization of the fibres and effect of coupling agents were evaluated in terms of various properties of the samples. The composite prepared with EFB:glass fibre ratio of 70:30 showed better reinforcing properties than that of others.

Mechanical properties of bio-fibers-reinforced high-density polyethylene composites: effect of coupling agents and bio-fillers

Bio-based fibers (wood and bamboo)-filled high-density polyethylene composites were prepared in a twin-screw extruder using two types of coupling agents: maleated polyethylene and glycidyl methacrylate-grafted polyethylene. The effect of bio-fibers used as filler on the mechanical properties of composites was studied. It was observed that mechanical properties such as tensile and flexural strengths of the composites with coupling agent increased with increasing filler loadings. Tensile strength and flexural strength exhibited improvement up to 66% and 90%, respectively, over virgin high-density polyethylene. The maximum enhancement in the properties was observed with wood pulp when compared with wood- or bamboo flour-filled composites. Effect of coupling agents on the performance of composites was evaluated at 30% filler loading with wood flour as the filler. The study suggested that glycidyl methacrylate-grafted polyethylene exhibited better tensile and flexural properties as compared with maleated polyethylene. Impact strength of the composites prepared with coupling agent was found to be more than uncoupled composites. Among the fiber type, the impact strength of wood-fiber-filled composites was superior than that of bamboo flour-filled composites. Moisture absorption study indicated that even at 40% filler loading, moisture gain by the wood fiber- and bamboo flour-filled composites was merely 1.55% and 2.60% after 600 h of water immersion test, which suggests encapsulation of filler material by the polymer matrix.

Enhanced thermal stability and flame retarding properties of recycled polyethylene based wood composites via addition of polyethylene/nanoclay masterbatch

Barrier and mechanical properties of wood powder composites based on recycled polyethylene (RPE) were modified using a commercial nanoclay masterbatch. X-ray diffraction, dynamic rheology and thermogravimetric analysis measurements showed that nanoclay from the selected masterbatch was well dispersed and formed a percolation network in both virgin and RPEs. The resulting nanocomposites promoted the thermal stability of matrix significantly. Modification efficiency of nanoclay, however, was evidently influenced by the type of matrix, where the strongest effect was achieved in a low viscosity virgin high density PE. The masterbatch was incorporated into an industrial formula designed extrusion quality RPE/wood flour composite. Processing procedures, mainly compounding cycles, and material composition, mainly clay content and type of coupling agent, were optimised. Two extrusion cycles led to higher uniformity of resulting composites than one cycle. Addition of a coupling agent, which has medium viscosity and plenty functional groups, led to enhanced tensile strength. The twice compounded composites were well stiffened and strengthened via combination of 6 wt-% clay and medium viscosity coupling agent. All composites without the addition of nanoclay burned faster after ignition and dripped much earlier and more compared to the composites containing nanoclay even with as small amount as 3 wt-% and being compounded once. The material with 6 wt-% clay showed the best sample integrity and burned slowest of all the tested composites. Furthermore, no dripping during combustion was seen for this material. This study shows that the incorporation of nanoclay using the selected masterbatch can effectively improve the flame retarding properties of RPE based wood composites.

Effect of a New Type of Coupling Agent on The Mechanical Properties of Various Multi-Walled Carbon Nanotube/Rubber Composites

In our experimental work application of carbon nanotubes in rubbers have been investigated. The effects of the type of the rubber matrix, the concentration of the carbon nanotubes and the effects of a coupling agent on the mechanical properties of the composites have been studied. The strength of the rubber matrix had great influence on the strengthening behaviour of the carbon nanotubes. By application of surface treated carbon nanotubes the strength of the composites made from a rubber matrix having the tensile strength under 10 MPa could be improved by 35%. However, the composites from the rubber with higher tensile strength contained treated carbon nanotubes afforded balanced performance against fatigue stresses probably due to the effect of the coupling agent and the homogenous distribution of the carbon nanotubes.

Effect of coupling agents on thermal, flow, and adhesion properties of epoxy/silica compounds for capillary underfill applications

Abstract In this study, the different silane coupling agents were added to epoxy/silica systems. The effects of the type of silane coupling agent in the epoxy/silica compounds on the thermal, flow and adhesion properties were investigated. The curing behavior was examined by differential scanning calorimetry (DSC), and the flow properties of the epoxy compounds were evaluated from penetration rate measurements. The adhesion strength as a mechanical property was determined by die shear strength testing. The silane coupling agent type had a significant effect on the thermal, flow and adhesion properties. The coefficients of thermal expansion (CTE) and adhesion of the DGEBF epoxy/SiO 2 systems could be enhanced by the addition of silane coupling agents. In addition, the penetration rate was increased by the addition of a coupling agent except for the CA-A coupling agent. This was interpreted in terms of the reactive functional groups and dispersion forces resulting in coupling agents on the interfaces between the DGEBF epoxy resin and silica.

Study of the covalently immobilized amyloglucosidase on macroporous polymer by mathematical modeling of the pH optima

BACKGROUND: A totally new approach has been applied for mathematical modeling of the enzyme activity/pH relationship, for quantification and distribution of enzyme activity in and out of carrier pores. This is a very simple and elegant method for determination of the distribution of enzyme molecules on the surface and inside the particles, simply through measurement of enzyme activity at different pH values. RESULTS: Amyloglucosidase (AG) from Aspergillus niger was covalently immobilized onto poly(GMA-co-EGDMA) by the glutaraldehyde and periodate methods. Mathematical modeling of the pH optima for two types of covalently immobilized AG resulted in higher enzyme amounts on the surface within periodate immobilizate (67%) in comparison with glutaraldehyde immobilizate (53%). These values are modified to 64.25% for periodate immobilizate and 49.95% for glutaraldehyde immobilizate when diffusion effects are taken into account. CONCLUSION: The mathematical model applied enabled observation of the difference between the two types of coupling agents and different immobilization procedures throughout quantification of the immobilized enzyme on the matrix surface and inside pores. Copyright © 2012 Society of Chemical Industry

Study on Impacting Performance of Bamboo-Plastic Composite

In order to research impacting strength of bamboo-plastic composite from bamboo powder content, particle size, type of coupling agent, etc. The bamboo-plastic composite is made of extrusion and injection molding process. Results show: when bamboo powder content is 30%, impacting strength of the material is the highest; the bamboo-plastic composite which made of Silane and MAPE has higher impacting strength than others; when PP: HDPE = 2:3, the impacting strength of the bamboo-plastic composite is the highest. Compared with these factors, the coupling agent on impacting strength is the most obvious influence.