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The tribological behaviors of polyetheretherketone reinforced by short glass fibers have been investigated using the ball-on-disc configuration at different applied loads under dry sliding and water lubrication. The effects of water and GF on the wear properties of the hybrid composite have been discussed. It was found that the glass fiber/polyetheretherketone composite showed excellent tribological performance in water lubrication. High wear resistance and low friction coefficient were achieved under a wide range of applied load. The glass fibers bore the main load between the contact surfaces and protected the matrix from further severe abrasion of the counterpart. At the same time, the cooling and boundary lubricating effects of water hindered the melting of glass fiber/polyetheretherketone surface layer which caused a great improvement in the trobological characteristic. Moreover, the transfer between the counterpart materials and the worn surface of the glass fiber/polyetheretherketone was inhibited accounting for the lower specific wear rate under water lubrication. The glass fiber/polyetheretherketone composite was characterized by mild scuffing and fiber protruding under water lubrication, while the plastic deformation and adhesion were significantly abated compared with those under dry sliding. [ABSTRACT FROM AUTHOR]

Hybrid composites of polycarbonate (PC) reinforced with short glass fibers (GF) and short carbon fibers (CF) were prepared by twin-screw extrusion and injection molding techniques. Composites were produced in different ratios of GF and CF by maintaining the total fiber loading at 40 wt%. The mechanical properties such as tensile, flexural strength, and impact of these composites were investigated. It was noted that an increase in GF content led to a higher strength of the hybrid composites as compared to CF. Morphological analysis by using scanning electron microscope reveals that CF had poor fiber-matrix interactions with PC, which brought about the decrement of stress-transfer efficiency. A poor fiber-matrix interaction is believed to be the main cause of the lower strength enhancement by CF than expected. Heat deflection temperatures of composites increased with the increment of GF content. From dynamic mechanical thermal analysis, high-storage modulus is observed at the temperature below Tg. Meanwhile, it was observed that surface and volume electrical resistivity decreased by increasing the CF content owing to its conductivity. [ABSTRACT FROM AUTHOR]

The chemical resistance of the glass/bamboo fibers reinforced polyester composites to acetic acid, sodium hydroxide, ammonium hydroxide, sodium carbonates, benzene, toluene, carbon tetrachloride, and water was studied. The hybrid fiber composites showed better resistance to these chemicals. Besides this, the tensile properties of glass/bamboo fibers reinforced polyester hybrid composites were studied. The effect of alkali treatment of the bamboo fibers on these properties was also studied. It was observed that tensile properties of the hybrid composites increased with glass fiber content. These properties were found to be higher when alkali treated bamboo fibers were used in the hybrid composites. The elimination of amorphous hemi-cellulose with alkali treatment leading to higher crystallinity of the bamboo fibers may be responsible for these observations. [ABSTRACT FROM AUTHOR]

The mechanical and water absorption behavior of the bamboo--glass mat (strand and woven) reinforced epoxy and polyester laminate composites are studied. The hybridization with glass mat increases the mechanical and water resistant properties of the hybrid composites. The increase in properties is higher in the woven glass mat reinforced hybrid composites compared to the strand mat. For both the epoxy and polyester matrix composites, when two layers of strand glass mat were used the mechanical properties increase, but with three layers it shows a decrease in value. Whereas, with woven glass mat reinforcement the mechanical properties increase as the number of glass mat layer is increased. Addition of glass fiber results in reduction of water absorption by the epoxy and polyester bamboo composites. Water absorption is reduced with increase in the glass fibers in the composite. [ABSTRACT FROM AUTHOR]

Glass fiber (GF)-reinforced biodegradable poly(propylene carbonate) (PPC) composites were prepared by melt blending. The effects of reinforcement on the mechanical, thermal, and morphological properties of the PPC/GF composites were investigated. The mechanical properties of the composites were found to be improved obviously by the incorporation of GF. Experimental results of the thermal properties indicated that the GF addition led to the improvement on the thermal stability of the composites, and that the Vicat softening temperature (VST) of the composites was much higher than that of pure PPC resin. Scanning electron microscopic examination revealed a uniform dispersion of GF within PPC matrix at low GF loading level. It was observed that the GF appeared to be oriented within the PPC matrix to some extent, and there was good interfacial adhesion between GF and PPC matrix. [ABSTRACT FROM AUTHOR]

The present experimental work is aimed at studying the performance of recycled newspaper and recycled newspaper/glass fiber hybrid polypropylene composites. The effects of glass fiber loading and maleic anhydride (MA) as a coupling agent on the tensile behavior and impact strength of composites containing 30wt% fiber were examined. The results suggest that the tensile strengths of the recycled newspaper/PP composites increase with increasing glass fiber content. A value of 55MPa for tensile strength and 4.1 GPa for the tensile modulus is achieved from a hybrid composite containing 10wt% of newspaper and 20wt% of glass fiber. The impact strength of the newspaper/PP composites progressively decreased with increasing glass fiber content. Adding (MA) by 2wt% in the composite formulation significantly improved both the dimensional stability and mechanical properties. Microstructure analysis of the fractured surfaces of modified composites confirmed improved interfacial bonding. Dimensional stability and strength properties of the composites can be improved by increasing the glass fiber content and or by addition of coupling agent. This project has shown that the composites treated with glass fiber and coupling agents will be desirable as building materials due to their improved stability and strength properties. [ABSTRACT FROM AUTHOR]

This article reports the mechanical characterization and sliding wear behavior of glass fiber-reinforced vinyl ester resins of varying acid values, based on epoxy-novalocs in the presence of three different comonomers (styrene, methyl acrylate and butyl acrylate) as reactive diluents. It presents a special account of the optimization of fabrication techniques of glass fiber-reinforced vinyl ester resin composites. It outlines optimum reaction conditions such as temperature, time, monomer type and initiator concentration. The experimental plan consisted of preparation of vinyl ester resin followed by the composite samples. Mechanical characterization was done and a comparison was made between the different samples. It was found that these composites have fairly good tensile and flexural properties. The composites with styrene and butyl acrylate as co-monomers had similar tensile strength which was higher than that of the composite with methyl acrylate. Hardness values of the three composites were almost the same without any significant effect of the comonomer type. Volumetric wear rate was estimated for these samples under various test conditions. A steady wear rate regime after certain amount of sliding was observed all the three cases. [ABSTRACT FROM AUTHOR]

Acrylonitrile butadiene styrene (ABS)/short glass fiber (SGF) composites were prepared. The effect of fiber volume fraction on the properties of composites was investigated, and test results were compared with theorical equations. SEM micrographs confirmed the reports in other studies that the adhesion between ABS and neat glass fiber is poor. Silane coupling agents with different organofunctional groups were used to improve the interface. The role of these coupling agents was studied by comparing processability, mechanical and physical properties of the composites containing different silane-treated glass fibers. It seems that using coupling agents, especially those with more effective functional groups, reduces the deviation of properties from theory. The affinity of different functional groups to ABS, as well as the strength of chemical and physical bandings formed during the reaction of silane modification, decides the effectiveness of the relative coupling agent. By properties and morphology analysis we concluded that tricholorovinyl silane seems to be the best coupling agent, for this composite. This conclusion is supported by the theorical possibility of forming stronger bands at the interface for this specific coupling agent. [ABSTRACT FROM AUTHOR]

Different samples of acrylonitrile-butadiene-styrene (ABS)/short glass fiber (SGF) composites were prepared. Varying processing conditions such as rotor rate, fiber volume, coupling agent type and amount, and also temperature were applied in order to investigate the effect of different factors on the final properties of the composite produced. All samples were tested physically, mechanically, and morphologically to investigate the effect of varying parameters mentioned above. The best fiber concentration, coupling agent, and temperature were found in a 30 wt% SGF composite coupled with 3 wt% of fiber tricholorovinyle silane and processed at 190°C (rotor rate=80 rpm) which showed the best properties compared with other samples. [ABSTRACT FROM AUTHOR]

Solid particle erosion of polymer composites is a complex surface damage process, strongly affected by material properties and operational conditions. To avoid repeated experimentation, it is important to develop predictive equations to assess material loss due to erosion wear under any impact conditions. This paper presents the development of a mathematical model for estimating erosion damage caused by solid particle impact on flyash filled glass fiber reinforced polyester composites. The model is based upon conservation of particle kinetic energy and relates the erosion rate with composite properties and test conditions. Another correlation derived from the results of Taguchi experimental design is proposed as a predictive equation for erosion wear of these fiber reinforced composites. Further, considering the complexity and high degree of nonlinearity in the erosion process, an artificial neural networks (ANN) technique is implemented as an effective tool for prediction of wear response of these composites in a larger space. Finally, the results of a mathematical model and the ANN model are compared with those obtained from experimentation. [ABSTRACT FROM AUTHOR]

The glass fiber (GF) reinforced epoxy composite samples used in this study are prepared by four different standardized methods, designated as Methods A, B, C, and D. The GF that is modified with silica particles and prestressed during curing in the composite system (Method D) is proved to be significantly superior as a potential candidate material for use in high impact applications. The impact property of the so-finished composite samples is compared, in turn, with other composite samples prepared by the other methods. There are clean fiber reinforced epoxy composite (Method A), modified GF reinforced epoxy composite (Method B), and prestressed clean GF reinforced epoxy composite (Method C). The results indicate that the impact property of the composites prepared by this novel Method D is greater by up to 100% in comparison with Method A and by lesser but, significant, amounts by the other two methods. [ABSTRACT FROM AUTHOR]

The objective of this study is to develop a new method of manufacturing glass fiber reinforced epoxy composites and to quantitatively show that the properties of such a new material are superior to that of a conventional fiber reinforced polymer composite of the same material base composition. To achieve this objective, the glass fiber (GF) reinforced epoxy composite samples are prepared in four different ways: Method A, using 'clean' GF as the reinforcement (i.e., with no modification or additional treatment to the as-received fiber); Method B, modifying the surface of the GF with silica particles before applying in the composite system; Method C, prestressing the clean GF during the curing procedure of the composite; and Method D, prestressing the silica modified GF during the curing procedure of the composite. Preparation by Method D is the newly developed method. The finished composite samples are tested by the three-point bend test and the short-beam shear test under ASTM standard conditions. The results indicate that the composites prepared by the new method, which include the GF surface modification and the GF prestressing preparation conditions, have an excellent combination of properties when compared to the specimens made by the other three methods. [ABSTRACT FROM AUTHOR]

The present literature suggests the need for investigating and characterizing the freeze-thaw response of polymer composites under different loading rates and also at ambient and sub-ambient temperatures. The present experiment has been carried out with three different weight fractions (i.e., 0.55, 0.6, and 0.65) of glass fiber-reinforced polyester composites. The short beam shear specimens are suddenly exposed to -80°C for 2 h and then a three-point bend test is conducted instantaneously at this temperature. Another batch of samples is allowed to thaw at ambient temperature for 1 h and tested on flexural mode at ambient temperature. The testing was carried out for a range of 0.5-500mm/min crosshead speed. The shear strengths at cryogenic temperature and thawing temperature are compared with the room temperature-tested data of the shear value of laminates. [ABSTRACT FROM AUTHOR]

Degradation of glass fiber-reinforced polyester composite by hydrothermal shock cycles is studied experimentally. The interface/interphase in glass fiber composites is assumed to be a polymer film, thus, it may be susceptible to perish through environmental shock. Glass fibers of 55, 60, and 65 wt% are used to fabricate polyester matrix polymer composites. The test specimens are first treated in a water bath of 50 °C for 30 min and then immediately immersed in another water bath at 100°C for the same time. The treatment is repeated for different cycles. The short beam shear (SBS) test is performed at room temperature on the conditioned samples for two different crosshead speeds (2 and 50mm/min). The objective of the experiment is to assess the deteriorative effect of hydrothermal shock on the interfacial bonding of varied weight fraction constituents in the composite. The fiber-matrix interfacial damage is reflected in the three-point SBS test. The fall in shear values is observed to be 19-27%, depending on the volume fraction of constituents. The variation in loading speeds is taken into consideration for the assessment of interlaminar shear strength (ILSS). [ABSTRACT FROM AUTHOR]