bluuebunny/crossref_metadata_2025_split huggingface dataset:
Schallemissionsmessungen an beschichteten Stahlblechen
Authors: Moslé H. G. , Wellenkötter B. 
Published: December 2004

AbstractDie Schallemissionsmessungen an unterschiedlich beschichteten Stahlblechen zeigten, daß es mit Hilfe dieses Verfahrens möglich ist, das Schädigungsverhalten dieser Werkstoffgruppe zu untersuchen.Bei den galvanisch beschichteten Blechen war die Schallemission bei gleichem Substrat abhängig von:

dem abgeschiedenen Metall
der Zusammensetzung des Elektrolyten
der Abscheidungsstromdichte
der Schichtdicke.
Die Untersuchungen an den phosphatierten und/oder lackierten Blechen zeigten eine Abhängigkeit der Schallemission von:

der Art der Phosphatierung
der chemischen Zusammensetzung des Lackes
der Höhe der Einbrenntemperatur
der Bewitterung
der Schichtdicke.
Bei den bisherigen Untersuchungen wurde die Schallemission lediglich als Impulsrate registriert. Um gezieltere Aussagen über Enthaftungen und Rißbildungen zu ermöglichen und um Haftungsmechanismen über die Enthaftungsvorgänge aufzuklären wurde begonnen, Amplituden‐ und Frequenzanalysen der Schallemission von beschichteten Metallen vorzunehmen.
Kohlenstoff‐faserverstärktes Al2O3 und Mullit
Authors: Yasuda E. , Schlichting J. 
Published: December 2004

AbstractDie Hydrolyse von Metallalkoxyden (Al‐tri‐sec‐butylat und Methylsilanester) läßt sich zur Herstellung von kohlenstoffaserverstärkten Al2O3‐ und Mullit‐Verbundwerkstoffen heranziehen. Hierbei zeigte es sich, daß für Al2O3‐Matrix eine zusätzliche SiC‐Zwischenschicht die Haftung zwischen Faser und Matrix verbessert. Die hergestellten Verbundwerkstoffe zeigen deutlich verbesserte Werte für die Bruchzähigkeit.
Aufbau und Eigenschaften glasfaserverstärkter Eisenverbundwerkstoffe
Authors: Abels U. , Bergmann H. W. 
Published: December 2004

AbstractAus Karbonyleisenpulver und gemahlenen Glasfasern, Duran 50®, gelang es, durch Mahlen und gemeinsame Höchstverformung mittels Strangpressen eine neue Werkstoffvariante herzustellen.Trotz des niedrigen E‐Moduls der Glasphase kommt es zu einer anomalen Festigkeitssteigerung der Komposite bei zum Teil guten Dehnungswerten. Der lineare Abfall des E‐Moduls und der Gleichstromleitfähigkeit des Verbundmaterials bis zu 50 Vol% des Additives erklärt sich aus dem fasergerüstartigen Aufbau in Verformungsrichtung. Die starke Dämpfungsabnahme im KHz‐Bereich und der starke Abfall der Wärmeleitfähigkeit ist durch Phononenstreuprozesse an den Phasengrenzflächen Glas/Metall bedingt, die aufgrund des gelockten Querschnittgefüges in mannigfaltiger Form vorliegen.
Untersuchung verschiedener Schweißverfahren für die Nickel‐Basislegierung NiMo 16 Cr 16 Ti
Authors: Merz D. , Poweleit B. , Thiessen W. 
Published: December 2004

AbstractDie allgemeine gute Korrosionsbeständigkeit der Nickelbasislegierung NiMo 16 Cr 16 Ti gegen den Angriff stark oxidierender Säuren sichert diesem Werkstoff ein breites Einsatzgebiet. Die Legierung ist mit umhüllten Stabelektroden und nach Schutzgasschweißverfahren gut zu verarbeiten. Bevorzugt sollte jedoch das Schutzgasschweißen eingesetzt werden, da erhebliche Analyseunterschiede zwischen dem niedergeschmolzenen Schweißgut aus umhüllten Stabelektroden und aus blanken Stäben und Drähten bestehen. Das unterschiedliche Schweißgut hat Einfluß auf das Korrosionsverhalten und die Warmformgebungsmöglichkeiten von geschweißten Konstruktionen.
Mechanical properties of mica‐reinforced polypropylene composites
Authors: Trotignon J. P. , Sanschagrin B. , Piperaud M. , Verdu J. 
Published: December 2004

AbstractThe influence of muscovite mica on the tensile, flexural, and mold shrinkage properties of composites with polypropylene (PP) were investigated. The best results in tensile and flexural properties at room temperature were observed for the physicochemical‐treated mica followed by silane‐treated mica. The mechanical properties could be correlated with the PP‐mica interactions, as observed in the scanning electron microscope (SEM). In the present study, with mica aspect ratio equal to about 30, the optimum performance was obtained for the average flake diameter 80 ⩽ d (μm) ⩽ 280. Finally, the results of coloration and weathering are discussed. It was found that the PP/30 percent mica formulation has superior weathering characteristics over the neat PP resin.
Industrial applications and properties of short glass fiber‐reinforced plastics
Authors: Santrach Drago 
Published: December 2004

AbstractShort glass fibers for reinforcements of plastics have been commercially produced for over three decades. During this period, they have been used in virtually every polymer, as well as in other matrices, such as concrete and plaster. Their tensile strength/cost performance is still three times that of Kevlar® and more than 30 times better than carbon fibers. Similarly, excellent modulus/cost performance and high temperature/cost performance can be achieved. This article gives a review of short‐fiber composites: their properties and use. Included is a comparison of compounding vs. in‐house blending, fiber/flake hybrids, and reinforced polymer blends. Finally, several new materials still in development stages will be examined.
Time‐dependence of crystal orientation in crystalline polymers
Authors: Stein R. S. 
Published: December 2004

AbstractThe results of two methods for studying molecular processes accompanying the deformation of polyethylene are described. The examination of spherulite deformation by observing light scattering patters along with measurement of the birefringence, stress and strain during the rapid extension of polyethylene shows that this initial structural deformation is essentially instantaneous. Dynamic x‐ray diffraction shows that this is followed by a slower relaxation involving change in the orientation of the crystals by two processes, the lower temperature one involving slipping of lamellae past each other and the higher temperature one involving viscoelastic flow of the crystals.
Effects of high hydrostatic pressure on the mechanical behavior of a crystalline polymer–polyoxymethylene
Authors: Sardar D. , Radcliffe S. V. , Baer E. 
Published: December 2004

AbstractThe true stress‐true strain behavior of polyoxymethylene, n(‐CH2O), as an example of a bulk semi‐crystalline polymer, has been investigated for constant hydrostatic environmental pressures from 1 atmosphere to 8 kilobars with the principal objectives of elucidating the factors controlling flow and fracture. Experiments were conducted in uniaxial tension at room temperature and constant strain rate. The tensile observations were supplemented by measurements of bulk compressibility and stress relaxation behavior at pressure.In contrast with metals and inorganic compounds, the modulus, yield stress and fracture stress of POM increase strongly with pressure by a factor of approximately three at 8 kilobars. The modulus increase is shown from the stress relaxation measurements to be associated with a pressure‐induced increase in the β‐transition temperature which points to the potential usefulness of the concept of pressure‐temperature super‐position of mechanical behavior. The characteristics of the pressure dependence of the yield stress demonstrate that yield criteria based on continum mechanics considerations, including the Mohr or Coulomb‐Navier criterion, are not valid for general deformation (non‐plane strain) conditions in this polymer. The concept of a critical volume change determining the initiation of yielding is suggested to be applicable to semi‐crystalline polymers. Comparison with analogous changes in yield stress with temperature points to an increasing contribution to the control of yielding by the initially disordered regions with increasing pressure or decreasing temperature. The fracture behavior observed at pressure eliminates the concepts of a critical stress as a fracture criterion for POM and of a simple reduction in normal stress at points of stress concentration as the principal effect of the applied pressure on fracture.
Effect of solvent treatments on the mechanical properties of nylon 6
Authors: Rubin J. , Andrews R. D. 
Published: December 2004

AbstractThe effects of absorbed solvents and chemical agents on the stress‐strain and dynamic mechanical properties of nylon 6 film have been examined. The agents investigated were: water, benzyl alcohol, phenol and iodine. These materials produce changes in the crystalline structure as well as plasticization when they are absorbed. Repeated introduction and removal of phenol indicated that the change of structure takes place completely during the first absorption; after that, the effects of absorption are reversible. The pure plasticizer effect can therefore be observed by comparison of a sample containing plasticizer and a sample from which the plasticizer has been subsequently removed. The general effect of absorbed plasticizer (except for iodine) seems to depend primarily on the amount of plasticizer absorbed, and very little on its exact chemical nature. However, different agents can produce different crystalline forms. A method of analyzing the stress‐strain curve is hypothesized based on the concept of a two‐phase solid state structure consisting of a crystalline lattice imbedded in an amorphous matrix.
A macroscopic analysis of composites containing layered spherical inclusions
Authors: Matonis V. A. , Small N. C. 
Published: December 2004

AbstractThis investigation considers a hypothetical three‐phase ordered composite to permit the design of a new material both stiffer and tougher than the matrix phase alone. The required elastic solution is greatly simplified and was based on a single layered inclusion in an otherwise infinite matrix under uniaxial tension. The solution presented is exact and generalized to accommodate any number of concentric layers of different thickness and composition.
Fine structures and fracture processes in plastic/rubber two ‐phase polymer systems. I. Observation of fine structures under the electron microscope
Authors: Matsuo M. , Nozaki C. , Jyo Y. 
Published: December 2004

AbstractFine structures of several plastic/rubber two ‐phase polymer systems were studied by means of direct observations of ultrathin sections under the electron microscope using osmium tetroxide staining and a hardening procedure developed recently by Kato. Samples used are several types of both ABS polymers and high ‐impact polystyrenes, and several PVC/rubber blends and the results were discussed in relation to their dynamic viscoelastic properties. It is suggested that these studies may fruitfully be extended to clarify the structure ‐to property relationships by use of this method.
The effect of penetrant activity and temperature on the anomalous diffusion of hydrocarbons and solvent crazing in polystyrene part I: Biaxially oriented polystyrene
Authors: Hopfenberg H. B. , Holley R. H. , Stannett V. 
Published: December 2004

AbstractThe effects of temperature and penetrant activity on the sorption kinetics and equilibria of a series of alkanes in glassy, biaxially oriented polystyrene were studied. Normal isomers of pentane, hexane, and heptane cause crazing of polystyrene film samples at high penetrant activities (> 0.85). Crazing kinetics are identical to the kinetics of Case II transport. Transport of these normal hydrocarbons in glassy polystyrene in the temperature range 25 to 50°C is markedly non‐Fickian; limiting Case II transport is observed at activities in exces of 0.6. Sorption appears to be controlled by highly activated relaxation processes including primary bond breakage at these high penetrant activities. Fickian diffusion behavior is approached, however, as penetrant activity is reduced. Sorption of the branched isomers of these compounds does not result in polymer microfailure. The sorption kinetics of the branched isomers, although time dependent, appear to be controlled primarily by thermally activated diffusion rather than large scale polymer relaxations which control Case II transport.
Mechanical behavior of polytetrafluoroethylene around the room‐temperature first‐order transition
Authors: Koo G. P. , Andrews R. D. 
Published: December 2004

AbstractThe effect of the room‐temperature first‐order transition on the plastic yield behavior of polytetrafluoroethylene (PTFE) has been investigated. Stress‐strain curves were measured at different strain rates and temperatures. Tensile creep under constant dead load was also measured as a function of temperature and stress level. The effect of degree of crystallinity was investigated by using both a rapidly quenched and slow‐cooled polymer. Observations were extended to large deformations, so that the phenomenon primarily observed was plastic yield rather than linear viscoelastic behavior.The curve of yield stress vs. temperature in the temperature range from –50 to +68°C was found to be almost identical with the curve of elastic modulus vs. temperature; the yield stress shows a marked local decrease at the first‐order transition. The yield elongation was almost constant (at about 5%) over this same range, which is in accord with the above result. The more highly crystalline polymer is always more rigid than the less crystalline polymer at small deformations, but above 19°C its stress‐strain curve shows a “cross‐over” in stress level with the curve of the less crystalline polymer as extension increases. That is, above 19°C the less crystalline polymer shows a more rapid rate of “strain hardening”, even though the strain‐hardening effect is pronounced in both polymers. Attempts to apply time‐temperature superposition to creep data at different temperatures were partially successful; the lateral shifts required corresponded to an activation energy of approximately 80 kcal.The experimental observations suggest a model of the solid‐state structure of PTFE which could be described as an “elastic‐plastic network”, in which crystalline domains are connected by elastic amorphous regions, and in which the crystalline domains can flow plastically at sufficiently high stress or temperature.
The mechanical and other physical properties of polyelectrolyte salts in the solid state
Authors: Nielsen L. E. 
Published: December 2004

AbstractSalts of polyacrylic acid can be fabricated in heated molds using mixed powders of polyacrylic acid and metal oxides. Because of the strong intermolecular forces in these polyelectrolyte salts, they have elastic moduli several times greater than the moduli of conventional plastics. They also have very low coefficients of expansion and high compression strengths. Composites containing metallic and inorganic fillers have also been made and their mechanical properties measured.
Some physical properties of multilayered films
Authors: Schrenk W. J. , Alfrey T. 
Published: December 2004

AbstractSome properties of multilayered films are summarized in relation to the properties of the component materials. Polymers may be selected for co‐extrusion into layered films to obtain various combinations of properties, such as barrier, stiffness, heat sealability, optics, and toughness. Properly chosen combinations of high and low modulus materials exhibit mutual interlayer reinforcement. Permeabilities of multilayer films can be calculated from layer geometry and individual component properties.
Entrance flows of polymeric materials: Pressure drop and flow patterns
Authors: Boles R. L. , Davis H. L. , Bogue D. C. 
Published: December 2004

AbstractFlow at the entrance of a tube or channel is of interest in many polymer processes. Except for mathematical treatments at high Reynolds numbers and in creeping Newtonian flow, one must turn to empirical correlating equations and qualitative observations. These are discussed in two parts, one on pressure drop and the other on flow patterns. The discussion of pressure drop is largely a review, dealing with inertial, viscous, and elastic contributions to the pressure drop in tapered and sharp‐edged entrances; also presented are new data for a viscoelastic polymer solution in tapered cone entrances. In the section on flow patterns, stress birefringent data for a very elastic solution flowing into a channel entrance show an unusual effect: stress discontinuities, not unlike “shock waves,” upstream and downstream of the entrances. This is in contrast to Newtonian and less elastic materials in which the stress patterns change gradually between the developed flow region and the entrance region.
Viscoelastic behavior of boron fiber‐epoxy resin composites
Authors: Schrager M. , Carey J. 
Published: December 2004

AbstractA torsion pendulum study of boron fiber‐epoxy resin composites has shown marked deviations, at elevated temperatures, from the predicted behavior. A new damping peak at approximately 180°C as measured at 5 Hz is present which appears to be independent of the type of epoxy resin present in the matrix. This peak is attributed to interfacial effects between the boron fibers and the matrix resin. A linear model is tentatively proposed to explain this effect.
The interaction of alkoxy silane coupling agents with silica surfaces
Authors: Kaas R. L. , Kardos J. L. 
Published: December 2004

AbstractThe interactions of γ‐aminopropyltriethoxy silane (A‐1100), γ‐methacryloxytrimethoxy silane (A‐174), γ‐glycidoxytrimethoxy silane (A‐187), and ethyltriethoxy silane (A‐15) with silica surfaces have been studied by means of infrared spectroscopy. The results indicate that the major force holding the silane to the silica surface after application from dilute solutions is primary chemical bonding. These bonds are formed by a condensation reaction between silanols on the hydrolyzed form of the silane and hydroxyl groups on the silica surface. In the case of the amino‐silane (A‐1100), hydrogen bonding was found to exist but was of minor importance in bonding the silane to the surface. In studying the effects of the addition of water, acetic acid, or n‐propylamine to various silane treating solutions, it was found that n‐propylamine has a unique catalytic effect on the condensation reaction. This catalytic effect explains the observation that γ‐aminopropyltriethoxy silane is more reactive than the other silanes studied. It is felt that silanes not containing an amine group can be made more effective if they are applied in the presence of an amine catalyst.
Crystallization studies on deformed polybutene‐1 melts
Authors: Wereta A. , Gogos C. G. 
Published: December 2004

AbstractAn apparatus was designed and built which allowed an investigation concerning the morphology and kinetics of crystallization of a deformed polybutene‐1 melt. The polymer was quenched from a temperature above its melting point to one of two crystallization temperatures. The supercooled melt was then sheared and allowed to crystallize isothermally while the internal stress in the melt was continuously recorded. A polarizing microscope was employed for the simultaneous study of the resulting morphological changes. By properly accounting for thermal contractions within the apparatus caused by the quenching operation, as well as the imposed shear strain, a strain history of the polymer during crystallization was developed. From this strain history and the assumption that the volume contraction resulting from crystallization was isotropic, approximate kinetics of crystallization in a deformed polymer melt were determined.
Lower Newtonian viscosities of polystyrene
Authors: Chee K. K. , Rudin A. 
Published: December 2004

AbstractA falling coaxial cylinder viscometer was used to measure the melt flow behaviour of a commercial polystyrene with Mw 260,000. The shear stress region extended down to 0.6 × 104 dynes/cm2 and shear rates were as low as 3 × 10−2 sec−1 at 186°C. The shear rate‐shear stress plots were linear at low shear stresses with slopes (differential viscosities) of 3.3 × 105 poises at total shear less than 120 units and decreasing differential viscosity with higher total shear. The flow curves at relatively low total shear were initially dilatant and became pseudoplastic with increasing shear stress. The inflection point represents a Newtonian apparent viscosity, which agrees fairly well with literature values for polystyrenes of the same Mw. Newtonian apparent viscosity is characteristic of a point value of shear stress and shear rate and is not necessarily a plateau region. Observation of a Newtonian region with decreasing shear stress or shear rate does not prove that this flow regime persists unchanged to zero values of the experimental parameter. The existence and magnitude of the Newtonian apparent viscosity reflects shear history of the polymer as well as its constitution and molecular weight distribution.
Application of holographic interference technique to mechanical studies of polymeric solids
Authors: Matsuoka S. , Wallder V. T. , Beauchamp H. L. 
Published: December 2004

AbstractHolographic reflective interference patterns arising from a small displacement of the surface of polymer solids provide a very sensitive means for detecting the internal stress related to molecular orientation, as well as measuring very small time dependent deformations not accessible by conventional means. Applicability of this technique using 6328Å laser light on various mechanical studies in polymeric solids is discussed.
Differential thermal analysis using high frequency dielectric heating II. Curing kinetics studies
Authors: Wald S. A. , Winding C. C. 
Published: December 2004

AbstractA previous paper described the theory and equipment of Differential Thermal Analysis using High Frequency Dielectric Heating, DTA/HF. Curing studies using DTA/HF on cis‐1,4‐polyisoprene rubber filled with 50 phr of CaCO3 and containing from 1.5 to 4.5 phr of dicumyl peroxide (DCP) curative indicated that below about 185°C, the curing reaction was first order with respect to DCP; the mean activation energy was 32.6 kcal/mole; and the heat of reaction ranged from 60 to 80 kcal/mole DCP. These results are in agreement with published results. Above 185°C both thermodynamic and kinetic evidence implied that the reaction mechanism changed; the first order peroxide decomposition no longer controlled the overall rate of reaction.The curing of both stereo styrene‐butadiene rubber (SBR) and cis‐1,4‐polybutadiene rubber (BR) containing 50 phr of CaCO3 and 0.5 phr of DCP was found to follow first order kinetics as expected. The magnitude of the heat of curing was used to determine the frequency of a vinyl propagation‐type cross‐linking reaction. Eight to 36 crosslinks per molecule of DCP were obtained. This reaction became more extensive at high temperature, in agreement with published results.