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Interfacial shear strength studies using the single-filament-composite test. I: Experiments on graphite fibers in epoxy
RESIN MA TRICES Analysis of the mechanical properties and microstructures of bamboo-epoxy composites Shin, F.G., Xian, X-J., Zheng, W-P. and Yipp, M.W. Journal o f Materials Science Vol 24 No 10 (1989) pp 3483-3490 The tensile, compressive, flexural and interlaminar shear properties of bamboo-epoxy composites are investigated. Also the disposition of the bamboo fibres, parenchyma cells and the epoxy matrix under different loading conditions are examined using scanning electron microscopy. Results show that bamboo-epoxy laminates have a specific strength and specific modulus three to four times that of mild steel. Microstructural studies reveal that the inclusion of bamboo fibres in a plastic matrix helps to overcome the problems of bamboo cracking due to desiccation and bioerosion. Bamboo-epoxy composites have excellent mechanical properties, and are produced from abundant natural resources, and thus have great potential for development as a building or general purpose material. A comparative assessment of bolted joints in a graphite reinforced thermoset vs. thermoplastic Walsh, R., Vedula, M. and Koczak, J. X A M P E Quarterly Vol 20 No 4 (1989) pp 15-19 Bearing strength in a graphite reinforced thermoplastic, AS4/PEEK, and a graphite reinforced epoxy, IM6/3501-6 are determined in order to make a comparative assessment of bolted joints in the two systems. Three test geometry types are considered; single bolt single lap, double bolt single lap and single bolt symmetrical double lap. Two specimens for each test type are prepared; laminate configuration type and matrix type. Specimens are loaded in tension. The thermoplastic AS4/PEEK composite shows superior bolted joint performance to the epoxy composite for both specimen types. The durability of controlled matrix shrinkage composites Part I Mechanical properties of resin matrices and their composites Lain, P.W.K. and Piggott, M.R. Journal o f Materials Science Vol 24 No 11 (1989) pp 4068-4075 The use of expanding monomer additions to control the cure shrinkage of thermosetting
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resins has potential to substancially increase their toughness. In this paper spiro ortho carbonates were added to several epoxy resin systems. Samples of cast resin and pultruded carbon fibre composite were tested for porosity and mechanical properties. Impact resistance was found to greatly improve with little loss tensile and compressive properties. An epoxy system incorporating a compatible solvent was made up for comparison. This system exhibited no improvement in impact resistance and a decrease in composite shear strength. Elastomeric matrix-short fibers adhesion Ibarra, L. and Chamorro, C. Polymer Composites Vo110 No 4 (1989) pp 256--260 This paper discusses the effect of a silicaphenol-formaldehyde dry adhesive system on the properties of a styrene-butadiene-rubber containing 20 percent of short polyamide fibres. Replacement of natural silicate in the adhesive system by a hydrated magnesium silicate was also considered. Samples were characterised by vulcanisation properties, green strength, storage and dynamic moduli. The adhesive system was found to enhance green strength, storage moduli and relaxation energies for the composite. This indicates a better fibre/matrix interface has been formed when the adhesive was used. Interfacial debonding in polyamide - 6/glass bead composites van Hartinsveldt, E.A.A. and van Aarsten, J.J. Polymer Vol 30 No I1 (1989) pp 1984-1991 Using the volume-strain method the debonding of glass beads from a polyamide-6 matrix during tensile testing is investigated. A series of composites are considered, having four different concentrations of filler beads, either with or without y-amino propyl methoxysilane (~/-APS) coupling agent. It is shown that an increase in filler concentration results in a decrease in stress and strain at the debonding point. Tensile strength is enhanced by use of y-APS coupling agent. A model is proposed in which the elastic behaviour of the composite with both bonded and debonded filler particles is considered. Interfacial shear strength studies using the single-filament-composite test. h Experiments on graphite fibers in epoxy Netravali, A.N., H e n s t e n b u r g , R.B., Phoenix, S.L. and Schwartz, P. Polymer
Composites Vo110 No 4 (1989) pp 226--241 The single-filament-composite (sfc) test is an experimentally very simple yet analytically complex method for obtaining on the interfacial properties and strength of a composite system. In this paper 6 different epoxy blends were tested and distributions of fibre fragment lengths were produced. Birefringence patterns were observed near fibre breaks. A SEM was used to determine fracture patterns and the existence of debonding. The observed distributions of fibre lengths were interpreted using a Monte-Carlo simulation of a Poisson/ Weibell model for fibre strength and flaw occurrence. It was concluded that the interfacial properties cannot be accurately predicted using the present simulation model without modification. Local matrix properties and fibre/matrix interactions were found to play a key role in composite strength. Plasticity of brittle epoxy resins during debonding failures Robertson, R.E., Sporer, M.G., Pan, T-Y. and Mindroiu, V.E. Journal of Materials Science Vo124 No 11 (1989) pp 4106-4113 Plasticity in two brittle epoxy resin systems was investigated using two resin systems. The debonding fracture surfaces of glass-epoxy interfaces and in epoxy bi-layers were examined using SEM. Plastic deformation resulted in ridges being observed from material having been pulled up from the surface by a substantial amount. Various shapes were noted; irregularly shaped circles, craters, parallel ridges of varying orientation and paraboloids. Thermal and shear softening effects were consiidered as explanations of these observations. Scanning electron microscopy and X-ray fluorescence analysis of a polymer blend, glass fibre composite Saini, D.R. and Schultz, J.M. Polymer Composites Vo110 No 4 (1989) pp ?22-225 The X-ray microanalysis mode on a scanning electron microscope was used to obtain qualitative information on the morphology and composition of a composite blend system. This paper outlines the experimental techniques used to study a glass filled polymer blend of poly(phenylene sulfide) and high density polyethylene.
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COMPOSITES. MARCH 1990
resins has potential to substancially increase their toughness. In this paper spiro ortho carbonates were added to several epoxy resin systems. Samples of cast resin and pultruded carbon fibre composite were tested for porosity and mechanical properties. Impact resistance was found to greatly improve with little loss tensile and compressive properties. An epoxy system incorporating a compatible solvent was made up for comparison. This system exhibited no improvement in impact resistance and a decrease in composite shear strength. Elastomeric matrix-short fibers adhesion Ibarra, L. and Chamorro, C. Polymer Composites Vo110 No 4 (1989) pp 256--260 This paper discusses the effect of a silicaphenol-formaldehyde dry adhesive system on the properties of a styrene-butadiene-rubber containing 20 percent of short polyamide fibres. Replacement of natural silicate in the adhesive system by a hydrated magnesium silicate was also considered. Samples were characterised by vulcanisation properties, green strength, storage and dynamic moduli. The adhesive system was found to enhance green strength, storage moduli and relaxation energies for the composite. This indicates a better fibre/matrix interface has been formed when the adhesive was used. Interfacial debonding in polyamide - 6/glass bead composites van Hartinsveldt, E.A.A. and van Aarsten, J.J. Polymer Vol 30 No I1 (1989) pp 1984-1991 Using the volume-strain method the debonding of glass beads from a polyamide-6 matrix during tensile testing is investigated. A series of composites are considered, having four different concentrations of filler beads, either with or without y-amino propyl methoxysilane (~/-APS) coupling agent. It is shown that an increase in filler concentration results in a decrease in stress and strain at the debonding point. Tensile strength is enhanced by use of y-APS coupling agent. A model is proposed in which the elastic behaviour of the composite with both bonded and debonded filler particles is considered. Interfacial shear strength studies using the single-filament-composite test. h Experiments on graphite fibers in epoxy Netravali, A.N., H e n s t e n b u r g , R.B., Phoenix, S.L. and Schwartz, P. Polymer
Composites Vo110 No 4 (1989) pp 226--241 The single-filament-composite (sfc) test is an experimentally very simple yet analytically complex method for obtaining on the interfacial properties and strength of a composite system. In this paper 6 different epoxy blends were tested and distributions of fibre fragment lengths were produced. Birefringence patterns were observed near fibre breaks. A SEM was used to determine fracture patterns and the existence of debonding. The observed distributions of fibre lengths were interpreted using a Monte-Carlo simulation of a Poisson/ Weibell model for fibre strength and flaw occurrence. It was concluded that the interfacial properties cannot be accurately predicted using the present simulation model without modification. Local matrix properties and fibre/matrix interactions were found to play a key role in composite strength. Plasticity of brittle epoxy resins during debonding failures Robertson, R.E., Sporer, M.G., Pan, T-Y. and Mindroiu, V.E. Journal of Materials Science Vo124 No 11 (1989) pp 4106-4113 Plasticity in two brittle epoxy resin systems was investigated using two resin systems. The debonding fracture surfaces of glass-epoxy interfaces and in epoxy bi-layers were examined using SEM. Plastic deformation resulted in ridges being observed from material having been pulled up from the surface by a substantial amount. Various shapes were noted; irregularly shaped circles, craters, parallel ridges of varying orientation and paraboloids. Thermal and shear softening effects were consiidered as explanations of these observations. Scanning electron microscopy and X-ray fluorescence analysis of a polymer blend, glass fibre composite Saini, D.R. and Schultz, J.M. Polymer Composites Vo110 No 4 (1989) pp ?22-225 The X-ray microanalysis mode on a scanning electron microscope was used to obtain qualitative information on the morphology and composition of a composite blend system. This paper outlines the experimental techniques used to study a glass filled polymer blend of poly(phenylene sulfide) and high density polyethylene.