Coupling Agent Content Research Articles

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.

Interfacial adhesion and thermal stability of high-density polyethylene glass fiber composites

The fiber-matrix adhesion and the thermal stability of glass fiber reinforced high-density polyethylene composites with increasing content of maleic anhydride coupling agent and zinc-based thermal stabilizer have been analyzed by the single fiber pullout test and oxidation induction time. High-density polyethylene compounds containing 8% by weight maleic anhydride grafted polyethylene increases the apparent interfacial shear strength to glass fibers by 3.5x; however, the strength was reduced by 45% with the addition of the thermal stabilizer. The thermal stabilizer was found to greatly improve the oxidative resistance. The oxidation induction time of the non-stabilized compounds is less than 1 min compared to over 25 min for the stabilized high-density polyethylene blends.

Facile strategy for preparing rhodamine B/ZrO2 composite fluorescent film with combined advantages of high emission intensity and outstanding water-resistance

The RB/ZF composite film prepared by immobilizing rhodamine B (RB) on ZrO2 film (ZF) exhibits strong fluorescence intensity but poor water-resistance. In this paper, rosin, octadecane-1, 18-dicarboxylic acid (OA) and silane coupling agent were used as hydrophobic modifiers to investigate the method to improve water-resistance of RB/ZF and maintain its strong fluorescence intensity as well. The influencing factors including modifier dosage, molecular structure, RB concentration and alkyl chain length of coupling agent on fluorescence performance and water-resistance of composite film were studied in detail and the related reasons were discussed. Results demonstrate that the film modified by the combination of rosin, OA and coupling agent has both favorable fluorescence performance and excellent water-resistance. The emission intensity of the optimized film is 94.5% of that of RB/ZF. Meanwhile, after immersion in various aqueous environments, there is no obvious difference in emission spectrum or intensity.

Effect of compression parameters on stress relaxation behavior of bamboo fiber reinforced polypropylene composites

AbstractA self‐made thermal mechanical analyzer was manufactured to characterized the compression and bending stress relaxation behavior for bamboo fiber reinforced polypropylene composite with different bamboo fiber and coupling agent concentration. The effects of bamboo fiber concentration, interfacial strength, load controlling method, compression speed, and temperature on composite stress relaxation parameters were investigated. The obtained results show that two‐stage relaxation process could be observed for both compression and bending test while shearing relaxation process was a single exponential decay. The relaxation time for slow exponential relaxation process was two orders of magnitude to that for fast relaxation process and the force decay amplitude on the first linear stage was about 3.5 times as much as that on the second exponential decay stage. Both the filling of bamboo fiber and coupling agent could increase the stress relaxation time but higher temperature would promote the movement of polymer chains and lengthen the stress relaxation time. The insights obtained from the experiments and fitting results can offer valuable reference to precisely controlling of dimensional accuracy and production efficiency for the composite products of irregular structure.

Modification Mechanism and Rheological Properties of Emulsified Asphalt Evaporative Residues Reinforced by Coupling-Modified Fiber

In order to solve the problems of the smooth surface of basalt fiber and its weak interfacial adhesion with emulsified asphalt cold recycled mixture, a silane coupling agent (KH550) was used to treat the surface of basalt fiber and the effects of treatment concentration and soaking time on fiber modification were studied. The influence of silane coupling-modified basalt fiber (MBF) on the rheological properties of emulsified asphalt evaporation residue was studied at high and low temperatures using three routine index tests: a dynamic shear rheological test (DSR), a bending beam rheological test (BBR), and a force ductility test. The elemental changes of the fiber before and after modification and the microstructure of the emulsified asphalt evaporation residue with the coupling-modified fiber were analyzed by Fourier infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray energy dispersive spectroscopy (EDS), which is used to study the modification mechanism of emulsified asphalt evaporation residue reinforced by coupling-modified fiber. The results indicate that the concentration and soaking time of the silane coupling agent have a great influence on the surface morphology and mechanical properties of the fiber, and that the optimal treatment concentration is 1.0% and the optimal soaking time is 60 min. The addition of coupling-modified fibers can reduce the phase angle and unrecoverable creep compliance of emulsified asphalt evaporation residue, increase the rutting factor and creep recovery rate, and improve the elastic recovery ability and permanent deformation resistance. However, excessive fiber will weaken the ductility of emulsified asphalt at low temperatures. The appropriate content of silane coupling-modified fiber (MBF) is 1.5%. After silane coupling modification, the fiber surface becomes rough and cohesion is enhanced between the fiber and the emulsified asphalt base. Silane coupling-modified basalt fiber (MBF) acts as reinforcement for stability and bridging cracks.

Effects of silane coupling agent modifications of hollow glass microspheres on syntactic foams with epoxy matrix

A syntactic foam was prepared from an epoxy resin matrix and modified hollow glass microsphere fillers. Modification by silane coupling agents with different molecular structures was analyzed, and the optimal content of the silane coupling agent was determined. The results demonstrated that all silane coupling agents enhanced the adhesion between the hollow glass microspheres and epoxy resin matrix, resulting in enhanced water absorption, compressive performance, tensile performance, and bending performance compared to those prepared using unmodified hollow glass microspheres. Among silane coupling agents with different end groups, the one with a sulfhydryl end group exhibited optimal modification for hollow glass microspheres. Among the silane coupling agents with different backbone structures, the one with silanol groups exhibited the optimal modification of hollow glass microspheres. Additionally, the performance of the syntactic foams was optimal when 6% of the silanol-containing coupling agent was used. The results demonstrated that syntactic foams prepared with hollow glass microspheres modified by silane coupling agents exhibited improvements in water absorption, compressive performance, tensile performance, and bending performance, compared with those prepared using unmodified hollow glass microspheres. Among silane coupling agents with different end structures, the one with a sulfhydryl group as end group showed the best modification effect on hollow glass microspheres. The water absorption was 0.35%, the compressive strength was 62.15 MPa, the tensile strength was 40.15 MPa, and the bending strength was 53.17 MPa. Among silane coupling agents with different backbone structures, the one with silanol groupsbonds showed the best results. Its compressive strength was up to 64.15 MPa, the tensile strength was 35.47 MPa, and the bending strength was 53.99 MPa.

Influence of coupling agent on post-consumption polypropylene composites reinforced with malt bagasse fibers

The aim of this work was to evaluate the influence of the use of coupling agent (CA) on the properties of thermoplastic composites produced from post-consumer polypropylene (rPP) and malt bagasse fibers (MB) of brewing industry. The CA used was maleic anhydride graft polypropylene copolymer (MAgPP). The study was carried out in two stages: in first step the best concentration of MB fibers was verified, where was varied the fiber contents between 0, 10, 20 and 30% (w/w); in the second step, the best MB concentration evaluated was used with different CA concentrations (0, 1, 3, 5 and 7% w/w). Of the three MB concentrations evaluated as reinforcing filler, the sample with a 30% (w/w) ratio presented 44% lower deformation than the others, presenting better mechanical resistance, although it also presented the highest water absorption. Thus, the 30% MB fiber content was chosen for two step, where the results showed that the PP/MB-30 composite treated with 3% (w/w) CA had a modulus of elasticity 10.3% higher than the same composite without CA, corroborating with the morphological analysis, which indicated better interfacial adhesion between composite components when CA was used. The PP/MB-30 composite treated with 1% (w/w) CA showed the highest thermal stability among all samples.

The Effect of 3-(Glycidoloxy Propyl) Trimethoxy Silane Concentration on Surface Modification of SiO2 Nanoparticles

SiO2 is widely used in nanocomposites as reinforcement nanoparticle to enhance mechanical properties especially wear resistivity. Prior to use, surface modification with proper and sufficient coupling agent should be performed on it. Coupling agent concentration plays a key role in modification process. In this study, the influence of 3-(glycidoloxy propyl) trimethoxy silane (GPTMS) concentration on surface modification of SiO2 nanoparticles, is experimentally investigated. The surface modification of nano-silica were performed by 30, 50, 80 and 110 wt.% of GPTMS in order to introduce the optimal GPTMS concentration to complete the process. Fourier Transformation Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Thermo Gravimetric Analysis (TGA) and X-Ray Diffraction (XRD) characterized the pure and surface modified samples; then, the results were compared to each other to achieve the aim of the research. FTIR results confirmed the silanization proceed due to the silane absorption peak disappearing and shifting of the hydroxyl group bonds in to the amide bonds. This test showed that 30 wt.% GPTMS has not been sufficient for full functionalization of the NPs. According to FESEM images, it seems that the NPs were better modified by 80 wt.% GPTMS due to the least NPs aggregation and lack of coupling agent deposition on the NPs. Also, TGA illustrates that this sample has higher thermal stability because of lower weight loss (11.2%) in coupling agent decomposition temperature range: 130–380 °C. Furthermore, X-Ray Diffraction confirmed the FESEM and TGA results about the mentioned sample due to its highest crystallite size (increase 26.64% in crystallite size in comparison with the pure sample). So, the 80 wt.% of GPTMS introduced as the optimal concentration for surface modification of SiO2 nanoparticles.

Effect of coupling agent content on properties of fly ash filled acrylic coating

Fly ash was modified with 0wt%, 1wt%, 2wt%, 3wt% and 4wt% silane coupling agent. Modified fly ash was mixed with acrylic emulsion and additives to prepare acrylic coating. Coating adhesion, cup drawing experiment and heat insulation test were conducted. Results show that, with the increase of the content of coupling agent, the adhesion and toughness of the coating decrease. And the coating modified with 4wt% silane coupling agent has the best thermal insulation properties.

Study surface modified nanocellulose whiskers in coconut shell

The nanocellulose whiskers degraded by coconut shell were modified by silane coupling agent (KH-570). The structure, morphology and dispersibility of modified nanocellulose whiskers were characterized and analyzed by infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM) and sedimentation. The results showed that the modified nanocellulose whiskers have been changed from hydrophilic to hydrophobic, and could be dispersed uniformly in ethanol without agglomeration because silane coupling agent reacts with hydroxyl groups on the surface of nanocellulose whiskers. The study showed that the crystallinity of nanocellulose whiskers were decreased with the increase of the content of coupling agent. Experiment also indicated that both of dispersibility and crystallinity could reached optimism when the amount of coupling agent is 2%. Finally, the mechanism of chemical reaction of coupling agent modified nanocellulose whisker in coconut huskwas estabilished by comparison of molecular structure of KH-570, modification process and the infrared spectrum of nanocellulose whiskers.

Sustainable Use of Biomass Boiler Ash as a Reinforcement Filler for Polyamide 6 Composite

The use of biomass combustion ash as a reinforcing filler has taken the attention in recent years to reduce the overall production cost and increase the mechanical properties of plastics. This study evaluates the effect of biomass boilers ash (BBA) as a reinforcing filler on polyamide 6 composites (PA6). The chemical composition and thermal stability of BBA were analyzed by X-ray fluorescence (XRF), Thermogravimetric analysis (TGA), and Differential thermal analysis (DTA) thermographs. Test samples were prepared by varying the ash content (2.5%, 5%, 7.5%, and 10%), and also samples were prepared without adding ash as a control. Moreover, surface modification was carried out by using N-2 (Aminoethyl) 3-aminopropyl triethoxy diamino-silane as a possible coupling agent for BBA and it was tested by varying the coupling agent concentration (0.5%, 1%, and 2%) by dry process and the samples were prepared by extrusion and injection molding processes. Comparative analysis of the degree of crystallinity, mechanical properties including tensile, flexural, and thermal properties were tested. The highest degree of crystallinity was obtained with 7.5% BBA-filled composites. The addition of 2% surface-modified BBA (SBBA) filled composites (PA6 / 10% Ash 2% CA) showed an increase of tensile strength and elongation at break than the 10% unmodified BBA (UBBA) (PA6/ 10% Ash) filled composites. Stress at peak and bending modulus values in the flexural test data were increased up to 10%. But it was significantly reduced with the increasing of modifying agent concentration due to the increment of stiffness of the composite.

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 coupling agent quantity on composite interface structure and properties of fiber metal laminates

AbstractEpoxy silane coupling agent A‐187 and amine silane coupling agent A‐1387 were used to modify the interface of carbon‐reinforced aluminum laminates (CARE), respectively. The effects of the type and content of coupling agent on the microstructure and mechanical properties of CARE were investigated. Results show that with the increase in the content of two coupling agents, the wettability first increases and then decreases. When the mass fraction of the two coupling agents is 1%, good wetting property is obtained, and the interlaminar shear and flexural strengths of the CARE plate are the best. Compared with epoxy coupling agent A‐187, amine coupling agent A‐1387 had better wettability to aluminum alloy surface and highly contributed to the improvement of interface structure and properties, which then increased the interlaminar shear and flexural strengths by 19.1% and 8.9%, respectively.

Development of Banana/Coir Natural Fibers Reinforced Polypropylene Hybrid Composites: The Effect of MA-g-PP (Maleic Anhydride Grafted Polypropylene) on Mechanical Properties and Thermal Properties

Banana/Coir fiber reinforced polypropylene hybrid composites was formulated by using twin screw extruder and injection molding machine. Specimens were prepared untreated and treated B/C Hybrid composites with 4% and 8% of MA-g-PP to increase its compatibility with the polypropylene matrix. Both the without MA-g-PP and with MA-g-PP B/C hybrid composites was utilized and three levels of B/C fiber loadings 15/5, 10/10 and 5/15 % were used during manufacturing of B/C reinforced polypropylene hybrid composites. In this work mechanical performance (tensile, flexural and impact strengths) of untreated and treated (coupling agent) with 4% and 8% of MA-g-PP B/C fibers reinforced polypropylene hybrid composite have been investigated. Treated with MA-g-PP B/C fibers reinforced specimens explored better mechanical properties compared to untreated B/C fibers reinforced polypropylene hybrid composites. Mechanical tests represents that tensile, flexural and impact strength increases with increase in concentration of coupling agent compared to without coupling agent MA-g-PP hybrid composites . B/C fibers reinforced polymer composites exhibited higher tensile, flexural and impact strength at 5% of Banana fiber, 15% of fiber Coir in the presence of 8% of MA-g-PP compared to 4% of MA-g-PP and untreated hybrid composites. The percentage of water absorption in the B/C fibers reinforced polypropylene hybrid composites resisted due to the presence of coupling agent MA-g-PP and thermogravimetry analysis (TGA) also has done.

Preparation of Inorganic Filler Modified Epoxy Resin Adhesive and Study on Its Compatibility with UDMH

Epoxy resin adhesive have many advantages that other adhesives do not have, and are widely used in various fields. At the same time, it is also a thermosetting resin with high crosslinking density. Its cured product is brittle, low impact strength, and easy to crack. These shortcomings limit the further application of epoxy resin. This article takes the plugging agent of UDMH as the starting point. Epoxy resin adhesive toughened and modified with two kinds of inorganic fillers, nano-titania and micro-alumina, were prepared and study the compatibility of modified epoxy resin adhesive with UDMH. It is found that under certain conditions, the silane coupling agent KH570 can undergo a grafting reaction with the hydroxyl groups on the surface of nano-TiO2 to improve its lipophilic and hydrophobic properties, and the effect is better than KH560, KH550; Through FT-IR, SEM, TG and other characterization methods, it is found that when the content of coupling agent is 15%, the effect of surface modification is the best. In the preparation of two kinds of inorganic filler modified epoxy adhesives, it is found that when the content of nano-TiO2 is 3%, the toughening effect is the best, and the impact strength can reach 36.78 KJ/m2; When the content of micro alumina is 60%, the toughening effect is best, and the impact strength can reach 28.43 KJ/m2. In general, the toughening effect of using nano-TiO2 is significantly better than that of alumina. In the study of the compatibility of the two kinds of filler modified epoxy resin adhesives with UDMH, it is found that when nano-titanium oxide is used as the filler, the compatibility of epoxy adhesive and UDMH is improved. However, when micro-alumina is used as the filler, the compatibility of epoxy resin adhesive and UDMH becomes worse.

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.

Fabrication of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) biocomposite reinforced wood fiber modified with mixed coupling agents CS-201 and KH550

To improve the interfacial adhesion and mechanical performance of biocomposite, titanate coupling agent CS-201 and silane coupling agent KH550 as the mixed coupling agents, poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) biocomposite reinforced wood fibers modified with mixed coupling agents were prepared via hot pressing process. The mixed coupling agents showed a good synergistic effect on improving the interfacial compatibility of of biocomposite. From SEM, it could be seen that the interfacial compatibility between wood fibers and P34HB were effectively enhanced by the mixed coupling agents. By FTIR spectroscopy, new chemical bonds could be observed between P34HB and wood fibers as a result of adding the mixed coupling agents. The thermal stability of the biocomposite was increased by adding the mixed coupling agents. DMA indicated that the temperature was negatively correlated with the storage modulus E' of the biocomposite. Compared to untreated biocomposite, the biocomposite treated with the mixed coupling agents displayed excellent mechanical properties (a 56 % and 200 % improvement in tensile strength and elastic modulus respectively). In addition, the synergistic enhancement effect was most significant when the content of the mixed coupling agent was 1%.

Synthesis and Properties of Polyimide Silica Nanocomposite Film with High Transparent and Radiation Resistance.

In order to prepare flexible glass cover sheet materials suitable for space solar cells, fluorinated diamine 2,2’-bistrifluoromethyl benzidine (TFDB) and fluorinated dianhydride 4,4’ (hexafluoroisopropyl) diphthalic dianhydride (6FDA) as the monomer, polyimide (PI)/SiO2 composite film was synthesized by in situ polymerization, and the influence of coupling agent and SiO2 nanoparticle content on the film structure and properties was studied. The results show that PI synthesized from fluorine-containing monomers has better light transmittance, and the highest transmittance can reach 91.4%. The average visible light transmittance of the composite film decreases with the increase of SiO2 content, and the transmittance of the film decreases less in the high-wavelength region and greatly decreases in the low-wavelength region. The tensile strength and elastic modulus of PI/SiO2 composite film increase with the increase of SiO2 content, first increase and then decrease, reaching the maximum when the content is 10%; while the elongation at break of the composite film gradually increases with the increase of SiO2 content reduce. The thermal stability of PI/SiO2 composite film increases with the increase of SiO2 content. The doping of nano-SiO2 significantly suppresses the influence of irradiation on the mechanical properties of the film.

EFFECT OF SILANE COUPLING AGENT CONTENT ON MECHANICAL PROPERTIES OF HYDROXYAPATITE/POLY(METHYL METHACRYLATE) DENTURE BASE COMPOSITE

In removable prosthodontics, poly(methyl methacrylate) (PMMA) is the most suitable for the construction of denture bases. Intra-orally, the subjected stress intensity during the function accelerate the fracture of acrylic resin denture bases. Extra-orally, fracture occurs when dentures are accidentally dropped on a hard surface. The aim of the current study was to investigate the effect of coupling agent concentration on the mechanical properties of Hydroxyapatite/Poly(methyl methacrylate) (HA/PMMA) denture base composite. The Hydroxyapatite (HA) treated with four different ratios (i.e. 0, 5, 7 and 10 wt%) of 3-(trimethoxysily) propyl methacrylate (γMPS) silane coupling agent was added into the PMMA matrix. The mechanical performance of the composite was evaluated by conducting fracture toughness, flexural and tensile tests. An improvement of 13.83% and 9.62% in the tensile and flexural strength respectively, was achieved. The tensile and flexural modulus of the composite increased by 19.04% and 12.5% respectively. A significant improvement of 29.26% in the fracture toughness was observed at 10 wt% of γ-MPS. 10 wt% of γ-MPS is the optimum amount of coupling agent for obtaining balanced mechanical properties.

High density polyethylene/wood flour composite: Optimization of processing temperature, processing time and coupling agent concentration

Wood plastic composites (WPCs) consisting of high density polyethylene (HDPE) reinforced with high-loading (55 wt%) of wood flour (WF) were fabricated with melt-blending technique. In this compounding method, processing parameters such as different mixing temperatures (of 165, 180 and 195°C), mixing times (of 5, 10 and 15 minutes) and coupling agent contents (of 2 and 4 wt%) were evaluated. Prepared specimens were analyzed with tensile, Izod, shore D, DMTA, short-term creep, DSC, TGA, water absorption and water contact angle characterizations. Results revealed that mixing temperature of 180°C, mixing time of 10 minutes and coupling agent concentration of 4 wt% were found as the best processing conditions. The mentioned conditions provided enhanced dispersion of WF particles within the HDPE matrix, due to optimum viscosity of the polymer melt and effective residence time of compound in the mixer, and beside them efficient interfacial adhesion between WF and polymer matrix.