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Glass Fiber Composites (glass + fiber_composite)
Selected AbstractsThe unidirectional glass fiber reinforced furfuryl alcohol for pultrusion.POLYMER COMPOSITES, Issue 6 2008The development of unidirectional glass fiber reinforced furfuryl alcohol (FA) composites has been conducted using an in situ polymerization method. The FA prepolymer synthesized in this study was prepared from blends of FA monomer and catalyst (p -toluene sulfonic acid). The process feasibility, and kinetic analysis of the unidirectional glass fiber reinforced FA composites by pultrusion has been investigated. From the investigations of the long pot life of FA prepolymer, the high reactivity of FA and FA/glass fiber, and excellent fiber wet-out of FA resin and glass fiber, it was found that the FA resin showed excellent process feasibility for pultrusion. A kinetic autocatalytic model, d,/dt = A exp(,E/RT),m(1,,)n, was proposed to describe the curing behavior of FA/glass fiber composites. Kinetic parameters for the model were obtained from dynamic differential scanning calorimetry scans using a multiple regression technique. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Improving the properties of LDPE/glass fiber composites with silanized-LDPEPOLYMER COMPOSITES, Issue 7 2009Felipe W. Fabris Low density polyethylene (LDPE) is a widely used thermoplastic. The dispersion of inorganic fillers in thermoplastic matrices such as polyethylene has been largely employed to improve some of its properties. However, interaction between both components is a major issue so the presence of a coupling agent is usually necessary to increase the interaction among the phases. In this study, LDPE chemically modified with vinyltriethoxysilane (VTES) was used as a coupling agent in glass fiber-reinforced LDPE. The composites were prepared in a mixing chamber and subsequently analyzed by tensile tests, rotational rheometry, and scanning electron microscopy (SEM). The mechanical properties were significantly increased by the use of small amounts of the coupling agent. Moreover, the rheological behavior and the SEM micrographs showed higher interaction between the matrix and the reinforcing phase in the composites containing LDPE modified with VTES, confirming the suitability of using this coupling agent in these systems. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source] Influence of Reactice Processing on the Properties of PP/Glass Fiber Composites Compatibilized with SilaneMACROMOLECULAR MATERIALS & ENGINEERING, Issue 4 2006Afonso H. O. Felix Abstract Summary: Composites of PP reinforced with 20 wt.-% of short glass fibers were prepared by extrusion using VTES as a coupling agent. The addition of VTES was performed via in-situ functionalization of PP and by a two-step process in which PP was functionalized before the composite preparation. The obtained samples were characterized using rheometry, mechanical tests and microscopy. Both processes allowed the fiber/matrix interaction to increase. It was found that the VTES content affected the viscosity of the system by means of three different mechanisms: reduction of , -scission reactions, decrease of fiber sliding and plasticizing effect on the matrix. Whereas the first two mechanisms increased the viscosity of the final composite after unreacted VTES removal, the third one reduced the viscosity during the process and contributed to fiber-length preservation. The effects of VTES and peroxide contents on the Young's modulus were closely related to their effects on the final fiber length, indicating the effectiveness of using VTES as a coupling agent. Comparison between in-situ functionalization and the two-step process with prefunctionalization showed that in-situ functionalization led to a lower degree of chain breakage, even when it was performed in the presence of peroxide. Scanning electron micrographs of PP/glass fiber composite prepared without coupling agent. [source] Effects of organo-montmorillonite on the mechanical and morphological properties of epoxy/glass fiber compositesPOLYMER INTERNATIONAL, Issue 4 2007Mazlan Norkhairunnisa Abstract Epoxy composites filled with glass fiber and organo-montmorillonite (OMMT) were prepared by the hand lay-up method. The flexural properties of the epoxy/glass fiber/OMMT composites were characterized by a three-point bending test. The flexural modulus and strength of epoxy/glass fiber were increased significantly in the presence of OMMT. The optimum loading of OMMT in the epoxy/glass fiber composites was attained at 3 wt%, where the improvement in flexural modulus and strength was approximately 66 and 95%, respectively. The fractured surface morphology of the epoxy/glass fiber/OMMT composites was investigated using field emission scanning electron microscopy. It was found that OMMT adheres on the epoxy/glass fiber interface, and this is also supported by evidence from energy dispersive X-ray analysis. Copyright © 2007 Society of Chemical Industry [source] Sensing of Damage Mechanisms in Fiber-Reinforced Composites under Cyclic Loading using Carbon NanotubesADVANCED FUNCTIONAL MATERIALS, Issue 1 2009Limin Gao Abstract The expanded use of advanced fiber-reinforced composites in structural applications has brought attention to the need to monitor the health of these structures. It has been established that adding carbon nanotubes to fiber-reinforced composites is a promising way to detect the formation of microscale damage. Because carbon nanotubes are three orders of magnitude smaller than traditional advanced fibers, it is possible for nanotubes to form an electrically conductive network in the polymer matrix surrounding the fibers. In this work, multi-walled carbon nanotubes are dispersed into epoxy and infused into a glass-fiber preform to form a network of in situ sensors. The resistance of the cross-ply composite is measured in real-time during incremental cyclic tensile loading tests to evaluate the damage evolution and failure mechanisms in the composite. Edge replication is conducted to evaluate the crack density after each cycle, and optical microscopy is utilized to study the crack mode and growth. The evolution of damage can be clearly identified through the damaged resistance parameter. Through analyzing the damaged resistance response curves with measurements of transverse crack density and strain, the transition between different failure modes can be identified. It is demonstrated that the integration of an electrically conducting network of carbon nanotubes in a glass fiber composite adds unique damage-sensing functionality that can be utilized to track the nature and extent of microstructural damage in fiber composites. [source] Polyester composites reinforced with noncrimp stitched glass fabrics: Experimental characterization of composites and investigation on the interaction between glass fiber and polyester matrixPOLYMER COMPOSITES, Issue 3 2008Volkan Cecen The primary purpose of the study was to investigate the anisotropic behavior of different noncrimp stitched fabric reinforced polyester composites. The effects of geometric variables on composite structural integrity and strength are illustrated. Hence, tensile, three-point bending flexural and short beam shear tests were conducted up to failure on specimens strengthened with different layouts of fibrous plies in noncrimp stitched fabric. The remark, based on the observations while tensile testing, is that the stress,strain curves of polyester based composites were linear in the direction of fibers. However, in the matrix dominated orientations nonlinear relation between the stress and the strain was observed. Another aim of the present work was to investigate the interaction between glass fiber and polyester matrix. The experiments, in conjunction with scanning electron photomicrographs of fractured surfaces of composites, were interpreted in an attempt to explain the interaction between glass fiber and polyester and were interpreted in an attempt to explain the instability of polyester resin,glass fiber interfaces. It was concluded that the polymer was either deposited between adjacent fibers or as widely separated islands on the fiber surface. Infrared spectra of the cured polyester and its glass fiber composite were obtained by Fourier transform infrared spectroscopy. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers [source] Nanofilled polyethersulfone as matrix for continuous glass fibers composites: Mechanical properties and solvent resistance,ADVANCES IN POLYMER TECHNOLOGY, Issue 3 2010M. Aurilia Abstract Polyethersulfone (PES) is high performance thermoplastic polymer; however, its applications are limited by the poor resistance to several classes of solvents. Fumed silica and expanded graphite nanoparticles were used to prepare nanofilled PES by a melt-compounding technique with the view to improve the barrier properties. Solvent uptake at equilibrium and solvents resistance of nanofilled PES compounds were investigated by three different methodologies: (1) weight increase by methylene chloride absorption in a vapor-saturated atmosphere, (2) solvent uptake of acetone at equilibrium, and (3) decay of storage modulus induced by acetone diffusion. The storage modulus decay was measured by means of dynamic mechanical analysis on samples immersed in an acetone bath. The collected data were fitted to an ad hoc model to calculate the diffusion coefficient. The produced nanofilled PES showed a significant improvement in barrier properties and considerable reduction in acetone uptake at equilibrium, in comparison with the neat PES. Nanofilled PES compounds were also used to produce continuous glass fiber composites by the film-stacking manufacturing technique. The composites exhibited, by and large, improvements in flexural and shear strength. Their solvent resistance was evaluated by measuring the variation of mechanical properties after exposure to acetone for 1 and 5 days. These tests showed that the composites produced with the nanocomposite matrix did not exhibit higher solvent resistance than those prepared with neat PES, probably because of the deterioration of the fiber/nanocomposite-matrix interfacial bond in the wet state. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:146,160, 2010; View this article online at wileyonlinelibrary. DOI 10.1002/adv.20187 [source] Mechanical properties of particulate-filler/woven-glass-fabric-filled vinyl ester compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2010L. Yusriah 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 Tg. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Mechanical properties of polypropylene matrix composites reinforced with natural fibers: A statistical approachPOLYMER COMPOSITES, Issue 1 2004J. Biagiotti This work presents a systematic and statistical approach to evaluate and predict the properties of random discontinuous natural fiber reinforced composites. Different composites based on polypropylene and reinforced with natural fibers were produced and their mechanical properties are measured together with the distribution of the fiber size and the fiber diameter. The values obtained were related to the theoretical predictions, using a combination of the Griffith theory for the effective properties of the natural fibers and the Halpin-Tsai equation for the elastic modulus of the composites. The relationships between experimental results and theoretical predictions were statistically analyzed using a probability density function estimation approach based on neural networks. The results show a more accurate expected value with respect to the traditional statistical function estimation approach. In order to point out the particular features of natural fibers, the same proposed method is also applied to PP,glass fiber composites. [source] Polymerization compounding composites of nylon-6,6/short glass fiberPOLYMER COMPOSITES, Issue 4 2003Wei Feng Nylon-6,6 was grafted onto the surface of short glass fibers through the sequential reaction of adipoyl chloride and hexamethylenediamine onto the fiber surface. Grafted and unsized short glass fibers (USGF) were used to prepare composites with nylon-6,6 via melt blending. The glass fibers were found to act as nucleating agents for the nylon-6,6 matrix. Grafted glass fiber composites have higher crystallization temperatures than USGF composites, indicating that grafted nylon-6,6 molecules further increase crystallization rate of composites. Grafted glass fiber composites were also found to have higher tensile strength, tensile modulus, dynamic storage modulus, and melt viscosity than USGF composites. Property enhancement is attributed to improved wetting and interactions between the nylon-6,6 matrix and the modified surface of glass fibers, which is supported by scanning electron microscopy (SEM) analysis. The glass transition (tan ,) temperatures extracted from dynamic mechanical analysis (DMA) are found to be unchanged for USGF, while in the case of grafted glass fiber, tan , increases with increasing glass fiber contents. Moreover, the peak values (i.e., intensity) of tan , are slightly lower for grafted glass fiber composites than for USGF composites, further indicating improved interactions between the grafted glass fibers and nylon-6,6 matrix. The Halpin-Tsai and modified Kelly-Tyson models were used to predict the tensile modulus and tensile strength, respectively. [source] Comparison of the roles of two shrinkage-controlled low-profile additives in water aging of polyster resin,glass fiber compositesPOLYMER COMPOSITES, Issue 5 2000G. Camino A model previously formulated or water sorption in polyester resin-glass fiber composites has been applied to the kinetic analysis of experimental data for two composites containing a hydrolysable (polyvinyl acetate-PVAc) and a non-hydrolyzable (polystyrene-PS) shrinkage-controlling low-profile additive (LPA) respectively. It was found that the equilibrium water uptake in the composites and their unreinforced matrix is not drastically affected by the type of LPA. The kinetics of water sorption in the composites, however, were substantially different. The PVAc composite displayed a two-stage sorption process, the first stage being attributed to diffusion combined with hydrolysis, and the second to matrix swelling and plasticizing. A maximum in the kinetic curve was observed, and was due to changes in water solubility inside the matrix during sorption. In contrast, the PS composite displayed the typical kinetics of materials with slowly increasing hydrophilicity. [source] Thermal Sensor to Monitor Mechanical Properties in Polymer/Fiber Composite MoldingTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2002David Rouison Abstract Multi-layered samples of 1) continuous fiber axially aligned and 2) random oriented mat glass fiber composites were manually prepared for a fiber content ranging from zero to 20% (vol.). The uniaxially aligned samples displayed linear relations between both normalized elastic modulus and normalized thermal conductivity, and fiber content, for axially applied load and heat flux. For the random mat composite samples, similar results were obtained, with symmetry displayed in the plane of the mat. In both cases, measured axial thermal conductivity permits an evaluation of the axial elastic modulus. The Mathis surface probe used (US patent #5,795,064) is demonstrated as a non-intrusive indirect method of obtaining thermal conductivity for heat flux parallel (i.e. axial or transverse) to the plane of a sample. The method shows potential for use as an in-line monitoring device for the mechanical properties of molded composites. Des échantillons multicouches de composites (1) de fibres continues alignées dans le sens axial et (2) de fibres de verre en natte orientées aléatoirement, ont été préparés manuellement pour une teneur en fibre comprise entre 0 et 20 % (vol.). Pour les échantillons alignés dans le sens uniaxial, on montre l'existence de relations linéaires entre la teneur en fibre et le module élastique normalisé et entre la teneur en fibre et la conductivité thermique normalisée, pour une charge et un flux de chaleur appliqués dans le sens axial. Pour les échantillons de composite en natte aléatoire, des résultats similaires ont été obtenus, avec une symétrie observée dans le plan de la natte. Dans les deux cas, la conductivité thermique axiale mesurée permet une évaluation du module élastique axiale. On démontre que la sonde de surface Mathis utilisée (brevet US # 5,795,064) constitue une méthode indirecte non intrusive pour obtenir la conductivité thermique pour un flux de chaleur parallèle (c.-à-d. axial ou transversal) au plan de la surface de l'échantillon. La méthode montre du potentiel en tant que dispositif de surveillance en ligne pour les propriétés mécaniques des composites moulés. [source] An acoustic emission study on the fracture behavior of continuous glass fiber/polypropylene composites based on commingled yarnPOLYMER COMPOSITES, Issue 7 2008Yantao Wang The fracture behavior of continuous glass fiber reinforced polypropylene composites made of commingled yarn in the form of biaxial (±±45°) noncrimp warp-knitted fabric, twill woven fabric, and swirl mat, respectively, was investigated by virtue of single edge notched tensile (SEN-T) specimens. These composite laminates were manufactured by compression molding and cooled at two different rates (1°C/min and 10°C/min) during the last processing phase of the laminates. The failure mechanisms were studied by acoustic emission (AE) analysis. AE amplitude ranges corresponding to the individual failure modes have been identified. For biaxial noncrimp fabric reinforced materials, the failure mechanisms involved in the fracture procedure are governed by the interface related failure events. Higher cooling rate, which is accompanied by better fiber/matrix adhesion, results in not only the increase in the relative proportion of high-amplitude failure events, but also the occurrence of a large quantity of fiber fracture events. For woven fabric and mat reinforced composites, fiber-dominated failure mechanisms result in the higher fracture toughness when compared with biaxial noncrimp fabric composites. Under this circumstance, the change in cooling rate only results in the difference in the relative frequency of the individual failure modes. In addition, it is found out that the initiation fracture toughness of SEN-T specimens can be easily assessed by marking the load value which corresponds to the first point of AE signals emitted stably in AE events-displacement curves. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] Nanofilled polyethersulfone as matrix for continuous glass fibers composites: Mechanical properties and solvent resistance,ADVANCES IN POLYMER TECHNOLOGY, Issue 3 2010M. Aurilia Abstract Polyethersulfone (PES) is high performance thermoplastic polymer; however, its applications are limited by the poor resistance to several classes of solvents. Fumed silica and expanded graphite nanoparticles were used to prepare nanofilled PES by a melt-compounding technique with the view to improve the barrier properties. Solvent uptake at equilibrium and solvents resistance of nanofilled PES compounds were investigated by three different methodologies: (1) weight increase by methylene chloride absorption in a vapor-saturated atmosphere, (2) solvent uptake of acetone at equilibrium, and (3) decay of storage modulus induced by acetone diffusion. The storage modulus decay was measured by means of dynamic mechanical analysis on samples immersed in an acetone bath. The collected data were fitted to an ad hoc model to calculate the diffusion coefficient. The produced nanofilled PES showed a significant improvement in barrier properties and considerable reduction in acetone uptake at equilibrium, in comparison with the neat PES. Nanofilled PES compounds were also used to produce continuous glass fiber composites by the film-stacking manufacturing technique. The composites exhibited, by and large, improvements in flexural and shear strength. Their solvent resistance was evaluated by measuring the variation of mechanical properties after exposure to acetone for 1 and 5 days. These tests showed that the composites produced with the nanocomposite matrix did not exhibit higher solvent resistance than those prepared with neat PES, probably because of the deterioration of the fiber/nanocomposite-matrix interfacial bond in the wet state. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:146,160, 2010; View this article online at wileyonlinelibrary. DOI 10.1002/adv.20187 [source] | |||||||||||||||||||||||||