Role of fillers on three‐body abrasive wear behavior of glass fabric reinforced epoxy composites

The article summarizes an experimental study on the abrasive wear behavior of particulate filled glass‐epoxy (G‐E) composites. The two fillers investigated were graphite and alumina. The wear behavior was assessed by rubber wheel abrasion tests. The tests were carried out for 270, 540, 810, and 1080 m abrading distances at 22 and 32 N loads. The worn surfaces were examined using scanning electron microscopy (SEM). The results showed varied responses under different abrading distance because of the addition of fillers in G‐E composites. Graphite filler, however, performed poorly resulting in significant deterioration in wear performance while the alumina filled G‐E composite showed improved abrasion resistance. Selected mechanical properties such as hardness, tensile strength, and elongation at fracture were analyzed for investigating wear property correlations. The SEM studies indicate the reasons for failure of composites and influencing parameters. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

The role of synthetic and natural fillers on three‐body abrasive wear behaviour of glass fabric–epoxy hybrid composites

Polymer matrix composites are a promising candidate in tribological applications due to possibility of tailoring their properties with special fillers. The comparative performance of Glass–Epoxy (G‐E) composites with influence of synthetic fillers such as graphite (Gr) and silicon carbide (SiC) and biobased natural filler jatropha oil cake (JOC) was experimentally investigated. All the composites were fabricated using vacuum‐assisted resin infusion (VARI) technique. The mechanical properties were studied in accordance with ASTM standards. The three‐body abrasive wear studies were carried out with rubber wheel abrasion tester as per ASTM‐G65 standard. Two different loads namely 22 N and 32 N with different abrading distances viz, 135, 270, 405, and 540 m are test parameters. The results reveal that addition of JOC in G‐E composites has significant influence on wear under varied abrading distance/load. Further, it was found that SiC filled G‐E composites exhibited better wear resistance compared to Gr/JOC filled G‐E composites. The operating wear mechanisms have been studied by using scanning electron microscopy. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Three‐body abrasive wear behavior of E‐glass fabric reinforced/graphite‐filled epoxy composites

The present article summarizes an experimental study on three‐body abrasive wear behavior of glass fabric reinforced/graphite particulate‐filled epoxy composites. The wear behavior was assessed by rubber wheel abrasion tests (RWAT). The angular silica sand particle sizes in the range 200–250 μm were used as dry and loose abrasives. The tests were carried out for 270, 540, 810, and 1,080 m abrading distances at 22 and 32 N loads. The worn surfaces were examined using scanning electron microscopy (SEM). The results showed varied responses under different abrading distance due to the addition of glass fabric/graphite filler into neat epoxy. It was observed that the glass fabric reinforcement to epoxy matrix (G‐E) is not beneficial to abrasive wear resistance. Further, inclusion of graphite filler to glass fabric reinforced epoxy composite performed poorly resulting in significant deterioration in wear performance while the neat epoxy showed better wear performance. Selected mechanical properties such as hardness, ultimate tensile strength, and elongation at fracture were analyzed for investigating wear property correlations. The worn surface features were studied using SEM to give insight into the wear mechanisms. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Influence of cenosphere filler additions on the three‐body abrasive wear behavior of glass fiber‐reinforced epoxy composites

The dry three‐body abrasive wear behavior of bi‐directional glass fabric reinforced epoxy composites with and without cenosphere filler have been studied using dry sand/rubber wheel abrasion tester. The angular silica sand particle sizes in the range 200–250 μm were used as dry and loose abrasives. The wear experiments have been conducted at two different loads viz., 22 and 32 N and different abrading distances viz. 270, 540, 810, and 1,080 m. The wear volume increases with an increase in load/abrading distance for all composites. From the experimental wear data it was observed that the abrasive wear of the composites dependent on the applied load and abrading distance. Further, the cenospheres filler inclusion in glass fiber reinforced epoxy (G‐E) composite showed poor abrasive wear performance. Scanning electron microscopy was used to study the morphology of the worn surface features of composites and to understand the mechanisms involved in the wear analysis. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Three‐body abrasive wear behavior of short jute fiber reinforced epoxy composites

In present investigation, the three‐body abrasive wear behavior of short jute fiber reinforced epoxy composites was studied. The effect of various parameters such as fiber loading, sliding velocity, normal load, and abrasive size on the abrasive wear rate of composite has been analyzed. Abrasive wear study has been carried out using a dry sand/rubber wheel abrasion tester. The abrasive wear and friction characteristics of these composites are analyzed successfully using Taguchi orthogonal array and analysis of variance. The experimental study reveals that sliding velocity, fiber loading, and abrasive size have greater influence on the specific wear rate of the composites. The results show that the specific wear rate of the composites decreases with the increase in sliding velocity whereas, with the increase in normal load the specific wear rate increases. The study also revealed that the coefficient of friction of the composites increases up to a certain value than decreases with the increase in normal load as well as sliding velocity. The worn surfaces of the abraded specimens were examined using SEM to understand the mechanism involved in material removal. POLYM. COMPOS., 270–278, 2016. © 2014 Society of Plastics Engineers     

Mechanical properties of particulate‐filler/woven‐glass‐fabric‐filled vinyl ester composites

Studies of the effect of particulate fillers on specific mechanical properties of vinyl ester epoxy (VE) reinforced with woven glass fiber composites were carried out with different filler types and particulate filler contents (1%, 3%, and 5% by weight). Two types of particulate filler were used, i.e., calcium carbonate (CC) and phenolic hollow microspheres (PHMS). The composites were prepared by using a hand lay‐up and vacuum bagging method. Woven glass fabric composites filled with particulate PHMS were observed to have better specific flexural strength and specific impact strength, as well as lower density, than those filled with particulate CC. Morphological features determined by scanning electron microscope (SEM) proved that the PHMS filler experienced good bonding in the VE matrix, a feature which contributed to the improvement in the properties of the composites. The incorporation of particulate fillers into the composites also influenced the storage modulus with a minimal effect on T_g. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers     

Two‐body abrasive wear behavior of particulate filled polyamide66/polypropylene nanocomposites

An experimental characterization of the abrasive wear behavior of clay and clay plus short carbon fiber filled polyamide66/polypropylene (PA66/PP) nanocomposites has been investigated. Two‐body abrasive wear studies were carried out using pin‐on‐disc wear tester under multi‐pass condition against the water proof silicon carbide abrasive paper. It was observed that the clay reinforcement is detrimental to the abrasive wear resistance of PA66/PP blend. A combination of clay and short carbon fiber in PA66/PP blend improved the abrasive wear performance than those of clay filled PA66/PP nanocomposites. Further, on the basis of microscopic observation of the worn surfaces, dominant wear mechanisms were discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Drape behavior of 3D woven glass‐epoxy composites

This article deals with the drapability of 3D woven glass fabrics for composite applications. The study focuses on forming a 3D fabric over the mold, the result is a preform, which generally is then injected with a polymer matrix by so called Liquid Composite Molding (LCM) technique. When draping pre–impregnated composites, the fabric is embedded in the epoxy resin as matrix material. Various drape models for dry and pre‐impregnated fabrics have been proposed in the work. Solidworks and ANSYS are the software used for modeling and simulation of 3D woven fabric composites. Given the linear density (tex) and density of E‐glass fiber, the radius of the yarn was calculated. So far the cross section of yarn is assumed to be perfectly circular in shape, keeping the perimeter of yarn constant the circular cross section was deformed into a race track shape which is a much more practical and realistic shape of a yarn cross section. After calculating all the required dimensions, all the three 3D woven structures namely angle interlock, warp interlock and orthogonal were developed in solidworks. All the parameters like total number of warp and weft yarn per unit distance and thickness of the fabric were kept constant in all three structures. The analysis is based on first principles and the parameters of yarn and fabric construction. Results obtained through simulation are reported. These are validated with experimental composite samples. The model used to predict drapability of 3D woven glass‐epoxy composite gives good results. Orthogonal structure proves to be the best as far as resistance to deformation is concerned. However, if a relatively more flexible and formable prepreg is desired, it is advisable to use angle interlock or warp interlock structures. Warp interlock 3D structure proves most beneficial for draping on a mold. POLYM. COMPOS., 37:472–480, 2016. © 2014 Society of Plastics Engineers     

Experimental investigation on the abrasive wear behavior of nanoclay‐filled EVA/LDPE composites

The article presents the results of experimental investigation on three‐body abrasive wear behavior of nanoclay‐filled EVA/LDPE (NC‐EVA/LDPE) composites. NC‐EVA/LDPE composites with and without compatibilizer were prepared by Brabender Co‐Twin extruder (Make: CMEI, Model: 16CME, SPL) and poly(ethylene‐co‐glycidyl methacrylate) was used as the compatibilizer. The mechanical properties were evaluated using Universal testing machine. In three‐body wear tests, silica sand particles of size 200–250 μm were used as dry and loose abrasives. Three‐body abrasive wear studies were carried out using dry sand/rubber wheel abrasion test rig. The effect of abrading distance on the abrasive wear behavior of neat EVA, EVA/LDPE, and NC‐EVA/LDPE composites was reported. The results showed that the wear volume loss is increased with increase in abrading distance and the specific wear rate decreased with increase in abrading distance. However, the presence of nanoclay filler in EVA/LDPE composite showed a promising trend. Abrasive wear volume of the composites was correlated with mechanical properties such as hardness, tensile strength, and percentage elongation. However, higher weight percentage of LDPE in EVA increased the wear rate. The results indicate that NC‐EVA/LDPE with compatibilizer composite exhibits good abrasive wear resistance compared with NC‐EVA/LDPE without compatibilizer. Attempts to explain these differing trends are made in this work by analyzing the features observed on the worn surface samples by employing scanning electron microscopy (SEM). POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Development and high stress abrasive wear behavior of milled carbon fiber‐reinforced epoxy gradient composites

Milled carbon fiber‐reinforced polysulfide‐modified epoxy gradient composites have been developed. Density and hardness increases with the increase of carbon fiber content in the direction of centrifugal force, which shows the formation of gradient structure in the composite. High stress abrasive wear test was conducted on the gradient composites by using a Suga Abrasion Wear Tester. Abrasive wear rate reduced on increase of milled carbon fiber content from 0.15 to 1.66 vol%. Reduction in abrasive wear rate in milled carbon fiber‐reinforced epoxy gradient composites has been attributed to the increase of hardness, presence of random milled fibers, and debris of composite materials, which gave resistance and reduced wear rate. There is a small decrease in specific wear rate on adding 0.15 vol% milled carbon fibers. Further decrease of specific wear rate is observed on adding 0.45 vol% milled carbon fibers. After 3 N load, there is a decrease in specific wear rate behavior on adding 0.45 vol% carbon fibers, which further decreases on adding 0.60 vol% of carbon fibers. There is a remarkable decrease in specific wear rate up to 5 N load for 1.66 vol% milled carbon fiber‐reinforced composite. Reduction in specific wear rate on adding milled carbon fibers is based on the formation of debris, which remained intact in their respective positions due to the interfacial adhesion between milled carbon fibers and epoxy resin. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

New developments in flame retardancy of glass‐reinforced epoxy composites

This work involves the development of novel glass fiber–reinforced composite materials containing a commercially available epoxy resin, a phosphate‐based intumescent, and inherently flame‐retardant cellulosic (Visil, Sateri) and phenol–formaldehyde (Kynol) fibers. The intumescent and flame‐retardant fiber components were added both as additives in pulverized form and fiber interdispersed with the intumescent as a fabric scrim for partial replacement of glass fiber. Thermal stability, char formation, and flammability properties of these novel structures were studied by thermal analysis, limiting oxygen index, and cone calorimetry. The results are discussed in terms of effect of individual additive component on thermal degradation/burning behavior of neat resin. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2511–2521, 2003     

Mechanical properties of fire‐damaged glass‐reinforced phenolic composites

Changes to the mechanical and physical properties of a glass‐reinforced resole phenolic composite due to intense radiant heat and fire are investigated. Fire testing was performed using a cone calorimeter, with the composite exposed to incident heat fluxes of 25, 50, 75 or 100 kW/m² for 325 s and to a constant flux of 50 kW/m² for different times up to 1800 s. The post‐fire tensile and flexural properties were determined at room temperature, and these decreased rapidly with increasing heat flux and heat exposure time due mainly to the chemical degradation of the phenolic resin matrix. The intense radiant heat did not cause any physical damage to the composite until burning began on exposure to a high heat flux. The damage consisted of cracking and combustion of the phenolic matrix at the heat‐exposed surface, but this only caused a small reduction to the mechanical properties. The implication of the findings for the use of glass‐reinforced resole phenolic composites in load‐bearing structures for marine craft and naval ships, where fire is a potential hazard, is discussed. Copyright © 2000 John Wiley & Sons, Ltd.     

Determination of mechanical properties of glass‐epoxy composites in high temperatures

The objective of this study is to determine the tensile, compressive, and shear properties of unidirectional glass/epoxy composite plates under room (∼20°C) and high (40, 60, 80, and 100°C) temperatures. Mechanical properties were determined according to the ASTM standards. A hot lamination press was used for fabrication of composite plates. For curing process, laminated plates were retained at a constant pressure (250 kPa) and 120°C during 2 h. And then, composite plate is cooled to room temperature at the same pressure. The fiber volume fraction of laminated composite plate is measured as 65%. Experimental results show that the mechanical properties (except for the transverse tensile strength) of glass/epoxy composites are reduced by increasing temperature. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Dynamic mechanical properties of three‐component composites (acrylic polymer/epoxy/SiO2) in the glass‐transition region

In previous studies, we reported the linear and nonlinear rheological properties of three‐component composites consisting of acrylic polymer (AP), epoxy resin (EP), and various SiO₂ contents (AP/EP/SiO₂) in the molten state. In this study, the dynamic mechanical properties of AP/EP/SiO₂ composites with different particle sizes (0.5 and 8 μm) were investigated in the glass‐transition region. The EP consisted of three kinds of EP components. The α relaxation due to the glass transition shifted to a higher temperature with an increase in the volume fraction (?) for the AP/EP/SiO₂ composites having a particle size of 0.5 μm, but the α relaxation scarcely shifted for the composite having a particle size of 8 μm as a general result. This result suggested that the SiO₂ nanoparticles that were 0.5 μm in size adsorbed a lot of the low‐glass‐transition‐temperature (T_g) component because of their large surface area. The AP/SiO₂ composites did not exhibit a shift in T_g; this indicated that the composite did not adsorb any component. The modulus in the glassy state (E′_g) exhibited a very weak &phis; dependence for the AP/EP/SiO₂ composites having particle sizes of 0.5 and 8 μm, although E′_g of the AP/SiO₂ composites increased with &phis;. The AP/EP/SiO₂ composites exhibited a peculiar dynamic mechanical behavior, although the AP/SiO₂ composites showed the behavior of general two‐component composites. Scanning electron microscopic observations indicated that some components in the EP were adsorbed on the surface of the SiO₂ particles. We concluded that the peculiar behavior of the AP/EP/SiO₂ composites was due to the selective adsorption of the EP component. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40409.     

Mechanical and tribological properties of glass–epoxy composites with and without graphite particulate filler

The objectives of this research article is to evaluate the mechanical and tribological properties of glass‐fiber‐reinforced epoxy (G–E) composites with and without graphite particulate filler. The laminates were fabricated by a dry hand layup technique. The mechanical properties, including tensile strength, tensile modulus, elongation at break, and surface hardness, were investigated in accordance with ASTM standards. From the experimental investigation, we found that the tensile strength and dimensional stability of the G–E composite increased with increasing graphite content. The effect of filler content (0–7.5 wt %) and sliding distance on the friction and wear behavior of the graphite‐filled G–E composite systems were studied. Also, conventional weighing, determination of the coefficient of friction, and examination of the worn surface morphological features by scanning electron microscopy (SEM) were done. A marginal increase in the coefficient of friction with sliding distance for the unfilled composites was noticed, but a slight reduction was noticed for the graphite‐filled composites. The 7.5% graphite‐filled G–E composite showed a lower friction coefficient for the sliding distances used. The wear loss of the composites decreased with increasing weight fraction of graphite filler and increased with increasing sliding distance. Failure mechanisms of the worn surfaces of the filled composites were established with SEM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2472–2480, 2007     

Effect of fiber loading and orientation on mechanical and erosion wear behaviors of glass–epoxy composites

For a composite material, its mechanical behavior and surface damage by solid particle erosion depend on many factors. One of the most important factors is the fiber content. Similarly, these properties are also greatly affected by the fiber orientation. In this work, a series of experiments were carried out to investigate the influence of fiber loading and fiber orientation on mechanical and erosion behavior of glass fiber‐reinforced epoxy composites. The composites were fabricated with three different fiber loadings (20, 30, and 40 wt%) and at four different fiber orientations (15°, 30°, 45°, and 60°). The conclusions drawn on the basis of the experimental findings are discussed, and composite with 30° fiber orientation shows better microhardness compared with other fiber orientations irrespective of fiber loading. Similar observations are also noticed for other mechanical properties of the composites, such as tensile strength, flexural strength, interlaminar shear strength, impact strength, etc. Finally, the morphology of eroded surfaces is examined using scanning electron microscopy (SEM), and possible erosion mechanisms are identified. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

A study of localized curing of glass‐filled composites using microhardness measurements

Extent of cure of hybrid composite systems is examined by conducting hardness measurements at different stages of the photopolymerization reaction and obtaining kinetic parameters that matched the experimental data. The materials are commercial dental composites based on bis[4‐(2‐hydroxy‐3‐methacryloyloxypropoxy)phenyl]propane resins with different photoinitiator concentrations as well as filler particle sizes and combinations. Samples (five per group) were made using nylon molds (2.5 × 5 mm) of the tested composites. The samples were light cured with a constant‐power light source for durations up to 20 s. After curing, all samples underwent Vicker's hardness testing of top and bottom surfaces. While there are significant differences in the polymerization behavior between the top and bottom locations for the tested composites, the corresponding growth exponent n, a kinetic parameter in the kinetic theory, is very close in all cases. For the tested materials the coefficient factor k is much lower for the bottom surfaces compared with the top surfaces. This reduction in the value of k is more severe for the material with a higher concentration of the photoinitiator as well as a higher percentage of glass filler particles in the wavelength range affecting the photopolymerization. It is argued that a relationship between k and the irradiation intensity can be used to quantify the decay of irradiated light with its penetration into the composites. The comparisons can be used to draw preliminary conclusions on the parameters controlling the effective depth of cure in a hybrid composite. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 426–431, 2005     

Properties of glass‐filled thermoplastic polyesters

The thermal, mechanical, and rheological properties of glass‐filled poly(propylene terephthalate) (GF PPT) were compared to glass‐filled poly(butylene terephthalate) (GF PBT). The impetus for this study was the recent commercial interest in PPT as a new glass‐reinforced thermoplastic for injection‐molding applications. This article represents the first systematic comparison of the properties of GF PPT and GF PBT in which differences in properties can be attributed solely to differences in the polyester matrices, that is, glass‐fiber size and composition, polymer melt viscosity, nucleant content and composition, polymerization catalyst composition and content, and processing conditions were kept constant. Under these controlled conditions, GF PPT showed marginally higher tensile and flexural properties and significantly lower impact strength compared to GF PBT. The crystallization behavior observed by cooling from the melt at a constant rate showed that GF PBT crystallized significantly faster than did GF PPT. Nucleation of GF PPT with either talc or sodium stearate increased the rate of crystallization, but not to the level of GF PBT. The slower crystallization rate of GF PPT was found to strongly affect thermomechanical properties of injection‐molded specimens. For example, increasing the polymer molecular weight and decreasing the mold temperature significantly increased the modulus drop associated with the glass transition. In contrast, the modulus–temperature response of GF PBT was just marginally influenced by the polymer molecular weight and was essentially independent of the mold temperature. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 889–899, 1999     

Kenaf‐filled biodegradable composites: rheological and mechanical behaviour

Biodegradable polymer composites, typically based on biodegradable polymer matrices and natural‐organic fillers, are gaining rising interest and importance over the last few years. Several natural‐organic fillers can be used but the most widespread so far is wood, in the form of fibres or flour. Alternative cellulosic fillers can ensure advantages in terms of resource utilization and properties of the final composite. In this work, Mater‐Bi^® based biodegradable composites were prepared with two kinds of wood flour, and directly compared with alternative composites containing kenaf fibres. The use of kenaf fibres allowed improved elastic modulus, tensile strength and interaction with the polymer matrix to be obtained, although the filler dispersion was worse. Rheological measurements evidenced higher viscosity and an increasingly elastic behaviour of the melt. Copyright © 2012 Society of Chemical Industry     

Mechanical and physical characteristics of cellulose‐fiber‐filled polyacetal composites

We investigated the mechanical and physical characteristics of composites composed of polyacetal [alternatively called polyoxymethylene (POM)] and cellulose fiber (CelF) derived from wood pulp [10–52 wt % (9.3–50.1 vol %)] without any fiber surface treatment. The modulus, deflection temperature under load, and thermal conduction coefficient of the POM/CelF composites were effectively enhanced with increasing CelF content, and the composites had an advantage of specific modulus compared to glass fiber (GF)‐filled POM. The flexural modulus of POM/CelF 40 wt % (38.2 vol %) was measured to be about 6 GPa, which was comparable to that of POM/GF 20 wt % (12.1 vol %). In the composites, the CelFs were distributed randomly as monofilaments, and the debonding of the interface between the fibers and POM matrices in the fracture faces was confirmed as less by scanning electron microscopy observation. The POM/CelF composites possessed lower specific wear rates than the POM/GF composites, and they had damping behaviors near that of neat POM. No clear dependence of the melt flow index of the base POM on these characteristics was observed, except on Charpy impact strength. The composites studied here were unique in their performance and ability to be designed in accordance with specific demands, and they could be potential replacements for mineral‐filled and GF‐filled POM composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010