bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical properties of polyethylene/ethylene vinyl acetate filled with calcium carbonate
Authors: Mitsuishi K. , Kodama S. , Kawasaki H. 
Published: December 2004

AbstractThe tensile behavior of polyethylene/ethylene vinyl acetate (PE/EVA) polymer blends filled with calcium carbonate (CaCO3) was studied using tensile and viscoelastic tests. The relations between tensile properties (modulus, strength, etc) of oriented and unoriented PE/EVA‐CaCO3, and void volume of polymer/CaCO3 interface, PE/EVA blend ratio, and CaCO3 content were investigated. The results indicated that the tensile strength and elongation of PE/EVA‐CaCO3 decreased with CaCO3 content and PE blend ratio for unoriented PE/EVA‐CaCO3 systems. In the case of oriented samples, the relative modulus (E/E, where E and E are the modulus of oriented composites and the modulus of oriented matrix, respectively) of PE/EVA‐CaCO3 is larger than that of PE/CaCO3 by increasing the EVA content relative to PE and CaCO3. The value of E/E can be simply expressed as the function of void volume and CaCO3 modulus to polymer matrix modulus.
Experimental determination of the evolution of internal stresses in a composite material: Case of a circular bilayered laminate glass‐resin
Authors: Wippler C. , Aboulfaraj M. , Schirrer R. , Pixa R. 
Published: December 2004

AbstractA nondestructive method is proposed to analyze the internal stresses of a circular bilayered laminate glassresin. It is based on the measurement by optical interferometry of small deformations of the laminate under the influence of temperature, time, or applied mechanical stresses of known value. For example, the stress induced by the curing of the thermosetting resin layer is determined and the postcuring relaxation of the stress is measured. Other possibilities or improvements of the method are indicated: The determination of the Young's modulus of the thermosetting resin as a function of time, the determination of the work‐hardening rate, and the determination of the ultimate properties of the laminate are just a few of them.
Elastic moduli and failure mechanism of composites made of spherical glass beads, of polyethylene using poly (4‐vinylpyridine graft butylacrylate) as an interface agent
Authors: Pegoraro M. , Severini F. , Di Landro L. 
Published: December 2004

AbstractGraft polymers were prepared by copolymerization of double bond terminated long chain poly(vinylpyridine), endowed with polar units interacting with glass, and butylacrylate (BA) having short groups interactive with polyethylene. These polymers were used to coat A glass beads which were mixed with polyethylene (PE) to obtain glass‐PE‐composites. Good adhesion due to the presence of the adhesive polymer, and to a glass hydrolyzing pretreatment, permits higher elastic moduli and higher tensile strengths than in their absence. The adhesive composition has some influence especially on the yield stress which is higher when using the g‐polymer endowed with longer BA branches. Theoretical predictions of the moduli are discussed and do not give satisfactory results when compared with the experimental values, except at low concentrations. Failure is observed to begin in the polar zone and its mechanism appears to be dependent on the presence or absence of adhesive.The experimental stress and strain at the beginning of failure are lower for untreated fillers. The specific volume variation \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{\Delta V}}{{V_O }} $\end{document} during the tensile test appears to be an important index of adhesion. Both the critical strain at which detachment begins and the slope of the \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{\Delta V}}{{V_O }} $\end{document} curve can be assumed as effective adhesion indexes.
Adhesion between polybutylene terephthalate and E‐glass. Measured with a microdebond technique
Authors: McAlea Kevin P. , Besio Gregory J. 
Published: December 2004

AbstractSingle‐fiber pullout tests are frequently used to characterize the interfacial adhesion between resin and fiber in reinforced composites. In this report, a fiber pullout experiment in which a drop of thermoplastic resin is sheared from a single fiber is described. Specialized apparatus, developed and constructed in our laboratory, as well as the techniques for sample preparation are discussed in detail. The interfacial shear strength of polybutylene terephthalate (PBT) in contact with silane‐treated E‐glass fibers is measured quantitatively.
Melt rheological properties of nickel powder filled polypropylene composites
Authors: Maiti S. N. , Mahapatro P. K. 
Published: December 2004

AbstractThe melt rheological properties of nickel powder filled polypropylene composites were investigated. The effect of filler concentration on shear stress‐shear rate data, melt viscosity and melt elasticity parameters were determined by using a capillary rheometer. The study shows that the materials follow a power law in viscous behavior over the entire range of shear rates investigated and that the viscosity increases and elasticity decreases as filler concentration is increased up to a critical value. However, beyond the critical filler content melt viscosity decreases while melt elasticity increases. The effect of temperature on the viscoelastic properties of filled polypropylene was also investigated.
Applications of diffuse reflectance fourier transform infrared spectroscopy to fiber‐reinforced composites
Authors: Cole K. C. , Noël D. , Hechler J.‐J. 
Published: December 2004

AbstractDiffuse reflectance Fourier transform infrared (FT‐IR) spectroscopy can be used to obtain infrared spectra directly from the surface of composite materials with little or no sample preparation. It is thus of interest as a nondestructive method for industrial inspection. In many cases, the IR spectra provide detailed information concerning the chemical composition and molecular structure of the material. The technique works particularly well for carbon‐fiber composites. This paper describes the principles involved, some factors which influence the quality of the spectra, and a number of examples of applications. These include the characterization of epoxy matrices (composition, curing, degradation), the detection of surface contamination, and the determination of the degree of crystallinity in poly(phenylene sulfide)‐based composites.
Mechanical and rheological properties of carbon black filled polyethylene
Authors: Malik Tariq M. , Carreau Pierre J. , Grmela Miroslav , Dufresne Alain 
Published: December 2004

AbstractThe mechanical and rheological properties of high density polyethylene filled with carbon black have been examined. Two sources of carbon black (one commercial and other obtained from a pyrolysis process) and various treatments have been studied. The rheological measurements in the melt state has been performed on a Rheometrics stress rheometer and a capillary rheometer. These materials possess outstanding hardness and toughness showing great potential for structural application. Comparison of carbon black from two sources showed that the carbon from the pyrolysis process has a good potential as a reinforcing agent. It was found that surface treatment reduces the particle‐particle interactions and improves the filler dispersion. The relationship between the yield stresses, filler percentage, surface modification by the coupling agents and mechanical properties is discussed.
Rheological study of mica‐filled polypropylene as influenced by a coupling agent
Authors: Rochette A. , Choplin L. , Tanguy P. A. 
Published: December 2004

AbstractThe rheological behavior of mica‐filled polypropylene (PP) composites was investigated within the domain of linear viscoelasticity. The effect of mica concentration and of a silane coupling agent on material functions such as the complex viscosity (η*), the storage modulus (G') and the loss modulus (G") was examined. The dimensions of mica flakes were measured before and after coating with silane. The affinity of PP for the treated and non‐treated mica was characterized. It was found that, for low mica concentration (<30% by weight) the composite exhibits the classical viscoelastic behavior of a homogeneous material. For higher mica concentration, the material shows a strong heterogeneity as evidenced by an important drift at low frequencies in a Cole‐Cole representation. It was also found that the presence of a silane coupling agent moves this critical concentration value up to 40% by weight.
High temperature polyimides, chemistry and properties
Authors: Scola Daniel A. , Vontell John H. 
Published: December 2004

AbstractSelected polyimide resins are capable of long term use at 316°C for over thousands of hours in an inert atmosphere, and approximately 2000 hours in air. This attractive feature of polyimides has provided an avenue for applications at elevated temperature (316°C) as adhesives, coatings, and secondary structures in the form of fiber reinforced polyimide composites. The chemistry and properties of thermoplastic and crosslinked polyimides, including addition‐type polyimides, will be discussed. The chemical considerations of both commercial and experimental polymer materials, Avimid N, PMR‐15, LARC TPI, IP‐600, L‐20, and L‐30 as they affect processing are reviewed. General physical, thermal, mechanical, and thermo‐oxidative stability properties of polyimides are presented Room temperature and 316°C mechanical properties of unaged and 1000 hr 316°C aged high temperature polymer composites will also be discussed.
Viscosity and die swell of acrylonitrile‐butadiene‐styrene filled with glass beads and glass fibers
Authors: Yilmazer Ulku 
Published: December 2004

AbstractShear viscosity and die swell ratio of acrylonitrile‐butadiene‐styrene filled with glass beads and glass fibers were measured. The relative viscosity of the composites increased with filler content, but decreased with shear rate. At low shear rates, fiber filled systems had higher relative viscosities than bead filled systems. At high shear rates, the opposite was observed. The die swell ratio of the unfilled material increased linearly with the logarithm of the shear rate. Systems highly filled with glass beads or fibers showed a maximum in the die swell ratio at medium shear rates. The magnitude of the maximum in the die swell ratio increased with the filler content and the die length, up to a certain length, in a series of dies that had the same radius. The presence of a maximum in the die swell ratio of the filled melts is explained by an order‐disorder phenomenon observed earlier by Wu.
Weld line studies on transfer‐molded thermosetting composite materials
Authors: Eduljee R. F. , Gillespie J. W. 
Published: December 2004

AbstractMultiple gating and the presence of inserts make weld lines (also known as knit lines) almost unavoidable in commercially produced moldings. These weld regions may be significantly weaker in strength than the bulk material away from the weld line. Hence, a molded section containing a weld line will only be as strong as the weld line, no matter how strong the surrounding bulk material. The influence of processing history on weld line performance is essential to optimally designed transfer‐molded composite products with discontinuous‐fiber‐reinforced molding materials. This study has therefore been directed toward experimentally characterizing the weld line strength of a bulk molding compund (BMC) and a thick molding compound (TMC) as a function of the mold temperature, fill time/fill rate, and the postbake operation.
Elastomeric matrix‐short fibers adhesion
Authors: Ibarra L. , Chamorro C. 
Published: December 2004

AbstractThis paper analyzes the effects of the addition of a three‐component dry type adhesive system on the properties of composite SBR (styrene‐butadiene rubber) material containing 20 percent short polyamide (5 mm length and 60 μm diameter). The curing times are extended and green strength is doubled. The replacement of the silica component in the system by a natural silicate is not only feasible, but proves to be favorable for certain properties, such as the storage modulus E′, which becomes less sensitive towards temperature changes. Dynamic property measurements provide evidence of an additional dispersion corresponding to the matrix‐fiber interface located around 40 to 50°C, which does not occur in the composites without adhesive. The activation energies of the main relaxation process of these materials are determined, amounting to 175 KJ/mol for the matrix and 250 KJ/mol for adhesive‐containing composites, as a consequence of the formation of strong bonds between both phases.
Parameters affecting interlaminar stresses in tapered laminates under static loading conditions
Authors: Daoust J. , Hoa S. V. 
Published: December 2004

AbstractTapered laminates by internal ply drop‐offs have been studied. An extensive finite element program has been developed for microcomputers using displacement formulation. A 20 node, three dimensional element was used. Parameters which can influence the strength of the laminate were studied. These parameters include the location of the drop‐off in the thickness direction, the degree of resin filling inside the drop‐off, the shape of the drop‐off, the effect of width of laminate, and the orientation of the lamina where the drop‐off was made. Locations of failure based on maximum stress criterion were btained. Crack growth stimulation was also performed by consecutive removal of failed elements. Results show that crack growth is not continuous.
Permeability characteristics of multilayer fiber reinforcements. Part II: Theoretical model
Authors: Adams Kurt L. , Rebenfeld Ludwig 
Published: December 2004

AbstractThe permeability characteristics of multilayer fiber networks generally differ from those of the constituent layers. In heterogeneous assemblies, the effective in‐plane permeabilities and flow anisotropies are governed by the high permeability layers or directions. Based on the observation that a transverse flow mechanism contributes to filling the low permeability layers, a semipermeable wall model has been constructed to analyze encroaching flows into multilayer systems. The model identifies three flow regimes: a region in which the layers act independently and are governed by single layer solutions, a region in which the layers act as a unified homogeneous system governed by the single layer solution with weighted average properties, and a region intermediate to these extremes. A comparison of model simulations and experimental data demonstrates that the model has good predictive capabilities.
Electrochemical polymerization of xylene derivatives on carbon fiber
Authors: Li Hong , Moshonov Aharon , Muzzy John D. 
Published: December 2004

AbstractElectrochemically initiated polymerization on carbon fibers is an attractive process for combining fibers with a polymer matrix. An aromatic monomer, α,α′‐para‐xylene, was successfully polymerized on carbon fibers in a three‐compartment electrolysis cell. A composite topreg with 40 volume percent of polymer was obtained. The polymer coating has a porous texture. The polymerization is rapid and efficient. Polymerization conditions and composite thermal properties are described.
Effects of reactive and non‐reactive fiber coatings upon performance of graphite/epoxy composites
Authors: Rhee H. W. , Bell J. P. 
Published: December 2004

AbstractInterlayers of controlled composition and thickness were applied to commercial graphite fiber bundles by electrochemical copolymerization, and the impact and interlaminar shear strength of composites from these coated fibers were examined. Glycidyl acrylate/methyl acrylate copolymers represented coatings that were reactive to the epoxy matrix during curing; acrylonitrile/methyl acrylate copolymers represented non‐reactive systems. The reactive systems showed 10 to 30 percent simultaneous improvement in impact and interlaminar shear strengths, while the non‐reactive system failed at the interlayer‐epoxy interface and showed no improvement. There is an optimum interlayer thickness of 0.1 to 0.15 micron; the possible reasons are discussed. A detailed scanning electron microscope study illustrates how the structure of the composite fracture surface varies with the systematic changes in interlayer reactivity, composition, and thickness. Determination of the locus of failure is discussed. The observations are consistent with the mechanical property measurements.
The significance of microcomposites as experimental models
Authors: Wagner H. D. , Rubins M. , Marom G. 
Published: December 2004

AbstractThis paper demonstrates the usefulness of careful experimental work with model composite materials, such as thin polymeric films in which single fibers are accurately positioned, in at least two respects: to assess the validity of a theory for a given physical property, and to accurately probe the effects of various parameters on the behavior of composites. Working with such model composites has obvious advantages, such as the full control of experimental parameters, the possibility of introducing perturbative effects in a controlled way, and the possibility of verifying theoretical models in the range of low fiber content. Indeed, macroscopic composite materials contain various types of defects and perturbative effects, such as fiber misalignment or slack, fiber‐poor regions, voids, etc., which bias any quantitative assessment of mechanical and physical properties, and preclude the accurate verification of theoretical schemes. One difficulty in working with microcomposite models, also recalled here, is the need for an appropriate “scaling‐up” procedure to the level of macroscopic composites.
Determination of matrix‐dominated mechanical properties of fiber composite lamina
Authors: Lyon R. E. , Schumann D. L. 
Published: December 2004

AbstractA test methodology that utilizes unidirectional, hoop‐wound tubes to determine matrix‐dominated mechanical properties of unidirectional fiber composite lamina is described. Longitudinal shear modulus and strength as well as transverse Young's modulus, transverse tensile strength, and transverse compressive strength are obtained from a single thin‐walled tube specimen and fixturing design. Data presented for two carbon‐fiber‐reinforced epoxy composite materials illustrate the simplicity and precision of the described procedure.
Processing effects and damage tolerance in poly(etheretherketone) composites
Authors: Uralil F. S. , Newaz G. M. , Lustiger A. 
Published: December 2004

AbstractThermoplastic composites in general have been found to display improved resistance to impact damage over their thermosetting counterparts. However, in earlier work, we presented data that suggested that in poly(etheretherketone) (PEEK) based composites, damage tolerance may be adversely affected if cooling rates are too slow in the processing of these parts. In this work, ultrasonic C‐scan and compression‐after‐impact testing were implemented on PEEK APC‐2 plaques cooled at three different cooling rates, in addition to toughened epoxy and bismaleimide plaques processed conventionally as a comparison. It was found that the damaged areas as measured ultrasonically varied significantly between the PEEK samples cooled at different rates, and that under the slowest cooling conditions, the damaged areas approached those of the thermosetting systems tested. However, because compressive strengths before impact were found to be greater on slow cooling, the differences in compression‐after‐impact were less dramatic than one would have expected from the C‐scan results alone. Variations in crystallinity as well as spherulite size were the source for the differences in damaged areas as well as in compressive strength.
Effect of surface treatment of pitch‐based carbon fiber on mechanical properties of polyethernitrile composites
Authors: Itoi Masaaki , Yamada Yukiharu , Pipes R. Byron 
Published: December 2004

AbstractThe effect of surface treatment of pitch‐based carbon fiber on a new engineering thermoplastic resin, polyethernitrile, was investigated. Pitch‐based carbon fiber (CF) was treated in two separate oxidizing solutions. In the first method, a nitric acid solution was used as an oxidizing agent. In the second method, a hydrogen peroxide solution was used. Both methods demonstrated that each of these solutions was a satisfactory oxidizing agent for the pitch‐based CF. These treated fibers were combined with polyethernitrile polymer by the powder impregnation method, and unidirectional laminates were obtained. Improvements in both interlaminar shear strength and transverse flexural strength were achieved. The laminates fabricated from the treated CF maintained the same longitudinal flexural strength as laminates from the untreated control. In addition, scanning electron micrographs of composite fracture surfaces also showed excellent bonding of the treated fiber.
Mechanical and microscopic investigation of whisker‐reinforced silicone rubber
Authors: Weber Mark E. , Kamal M. R. 
Published: December 2004

AbstractFranklin Fiber whisker‐reinforced silicone rubber composites were molded using both transfer and compression molding. Processing parameters, such as sprue design, milling procedure, and mold temperature were varied. The fiber orientation in the composites is anisotropic and independent of sprue design and mold temperature, but dependent on milling procedure. Fiber attrition is significant for all samples. The Young's modulus is affected by fiber orientation. The experimental modulus values are higher than those predicted by the Halpin‐Tsai equations for short fibers.
Analysis and characterization of prepreg tack
Authors: Ahn K. J. , Seferis J. C. , Pelton T. , Wilhelm M. 
Published: December 2004

AbstractAs part of an engineering analysis and experimental methodology to characterize prepreg tack, a compression‐to‐tension test was optimized to enhance reproducibility and generate intrinsic property data. With the resulting stress‐strain compression and tension data, a theoretical model was developed to describe tack as a bulk viscoelastic property of a prepreg laminate stack. Using the viscoelastic analysis, four intrinsic material parameters to characterize prepreg tack could be defined. These were 1) relaxed modulus, 2) unrelaxed modulus, 3) relaxation time, and 4) initial void content of the prepreg stack. Relaxed and unrelaxed moduli of the prepreg stack were independent of temperature, while the relaxation time was highly dependent on temperature and matrix viscosity. In addition, the relaxation time was found to be influenced by resin/fiber content and prepreg surface characteristics, which also influenced the void content of the prepreg stack. Using these measured parameters, good agreement was observed between theory and experimental data for both the stress‐strain curve of the tack test and the simplified compression tack index (CTI*), defined as the ratio of output energy of the prepreg stack during tensile unloading to input energy during compressive loading.
The effects of additives on curing properties, resin contents, and mechanical properties of graphite/epoxy composites
Authors: Shu Wen‐Yung , Lin King‐Fu 
Published: December 2004

AbstractThe effects of additives such as boron trifluride‐monoethylene amine (BF3MEA) and fumed silica in the TGDDM/DDS epoxy formulations on the curing properties, resin contents, and mechanical properties of their graphite/epoxy (Gr/Ep) composites were investigated. The addition of BF3MEA increased the viscosity of resin as well as the resin contents of cured laminates because of its catalytic effect. Although the fumed silica was considered a thickening agent, it also acted like a co‐catalyst with BF3MEA. As the resin content of cured laminates was increased, the excess resin was likely to accumulate in the interlaminar region, which increased the interlaminar shear strength but decreased the flexure strength as well as the interlaminar fracture toughness value, GIC.