bluuebunny/crossref_metadata_2025_split huggingface dataset:
A crystalline ethylene, acenaphthylene, n‐hexene‐1 terpolymer exhibiting both high modulus and high elongation
Authors: Bailey F. E. , Walter E. R. 
Published: December 2004

AbstractPolyolefins are generally known either as partially crystalline thermoplastics or as elastomers. With the finding in the ethylene‐acenaphthylene copolymer system of the unusual properties of high crystallinity, high modulus, and no independent beta thermomechanical transition at high comonomer contents, it appeared that it might be possible to prepare a block polymer system which would retain the desirable low temperature transition near −110°C and “hard” acenaphthylene copolymer segments as well. Attempts were made, and the resulting terpolymer is described. An intermediate crystallinity polymer of apparently broad composition distribution was obtained with the modulus of high density polyethylene but the elongational characteristics of low density polyethylene.
Effect of matrix ductility and interface treatment on mechanical properties of glass fiber mat composites
Authors: Gaggar S. K. , Broutman L. J. 
Published: December 2004

AbstractThe influence of matrix properties on randomly oriented glass fiber epoxy composites has been studied. It is shown that an increased ductility (flexibility) of the matrix does not result in greater elongation to failure of the composite under tensile and flexural loads. The tensile (and flexural) strength and the modulus of elasticity are decreased as the ductility of the resin is increased. It is concluded that since the matrix material is subjected to a triaxial state of stress when the composite specimen is subjected to uniaxial loads, the effect of matrix modulus, Poisson's ratio, and yield strength are more important than the matrix ductility measured under uniaxial stress. The effect on mechanical properties of various surface treatments applied to the fibers is also investigated. Finally, scanning electron micrographs are presented showing matrix cracks, fiber debonding, and fiber pull‐out.
Prediction of vinyl chloride monomer migration from rigid PVC pipe
Authors: Berens A. R. , Daniels C. A. 
Published: December 2004

AbstractData on the solubility and diffusion of vinyl chloride monomer (VCM) in PVC resin powders have been combined with published solutions of Fick's diffusion equation to yield predictions of the amount and rate of loss of residual VCM (RVCM) from rigid PVC pipe under storage and service conditions. The principal factors controlling VCM migration are the initial VCM content, thickness of the PVC section, temperature and the age of the PVC product. Analysis Solutions are presented for RVCM loss from freshly exturded pipe (uniform VCM concentration) into either the storage environment or the pipe contents. From these solutions, estimates are made for the real‐world situation of closed‐system service following variable storage periods. The validity of this approach for rigid PVC pipe in water‐service is supported by reasonable agreement between its predictions and experimental laboratory data on the VCM content of water stored in PVC pipes. Both the predictive model and experimental data indicate that PVC pipe containing ≤ mg/kg (1 part per million) residual VCM will result in VCM concentrations in water of less than 0.002 mg/kg ‐ under any expected service conditions.
Prediction of polyethylene melt rheological properties from molecular weight distribution data obtained by gel permeation chromatography
Authors: Shah Basit H. , Darby Ron 
Published: December 2004

AbstractA method is presented for predicting rheological characteristics, such as shear dependent (non‐Newtonian) viscosity and components of linear oscillatory (complex) response functions for polyethylene melts from molecular weight distribution data obtained from gel permeation chromatographic (GPC) analysis. The results are compared with measured values of the rheological functions obtained from a variety of instruments over an extensive range of shear rates‐and frequencies. The agreement between predicted and measured rheological functions is quite good for high density resins. However, for a low density resin the agreement is not as good, although still reasonable over a considerable range of conditions. It is concluded that the quality of the GPC data is the key factor in the degree of success of the method.
Fracture of fiber reinforced composites
Authors: McGarry Frederick J. , Mandell John F. , Wang Su Su 
Published: December 2004

AbstractCharacteristics of the fracture of fiber reinforced plastic composites are described in terms of the elastic stress distribution at the crack tip, the mechanism of crack tip damage, and the modes and conditions of final fracture. The three‐dimensional, stress field at the tip of a sharp crack in a laminate is presented and contrasted to traditional two‐dimensional models. The response of the material in the form of inter‐ and intraply damage formation and growth under increasing load is characterized, and its effect in blunting the main crack is examined. The final fracture conditions, which may range from quasi‐brittle to notch insensitive, are discussed and related to the damage zone extension. Observed and anticipated effects of various material and geometric parameters are also discussed.
New techniques for mixing viscous reacting liquids. Part I. Mechanical means to improved laminar mixing
Authors: Rotz Christopher A. , Suh Nam P. 
Published: December 2004

AbstractA discussion of the basic mechanisms and governing laws for liquid mixing is used to motivate new design concepts for more efficient mixing equipment. In this part of the paper, the use of V‐grooves in the inner cylinder of a concentric cylinder mixer is examined. The purpose of the grooves is to induce vortex‐like motions in the fluids in order to overcome the negative effects of interface orientation on mixing performance. Results show that the grooves are efficacious in increasing the effectiveness of the mixer. Descriptions of the experimental and analytical work done to characterize the design and to prove its efficacy are presented in detail. Scale‐up parameters are also discussed.
A critical examination of the prepreg resin flow experiment
Authors: Roller M. B. 
Published: December 2004

AbstractThis paper takes a critical look at the applicability of the currently accepted Resin Flow Method of prepreg evaluation. The Resin Flow test is generally a high pressure, small dimension lamination experiment which is used to characterize materials processed tit high pressures and large dimensions. Several simple experiments are described which support previously reported theory and provide a basis‐for more meaningful comparison of materials based on appropriate scaling via an analytical flow model.
An experimental technique for predicting foam processability and physical properties
Authors: Bigg Donald M. , Preston Joseph R. , Brenner Douglas 
Published: December 2004

AbstractThermoplastic foam properties and processing stability depend strongly on the ability to obtain the proper rheological properties for the polymer melt at temperatures where the decomposition of a chemical blowing agent may be controlled. An experimental technique has been developed which allows stable processing conditions to be determined for the continuous extrusion of foamed thermoplastics with known foam properties. The technique involves a thermal analysis of the polymer‐blowing agent formulation to determine the range of controllable extrusion temperatures. Rheological analysis was carried out using a slit die to establish a relationship between the thermal blowing characteristics of the polymer composition and rheological data which correlate with foam extrudability and the physical properties of the foam. This provides a means of predicting both processability and foam properties which aid in the scale‐up to production. The rheological‐foam property correlations were confirmed by continuous foam extrusion on a laboratory extruder.
Finite element analysis of calendering
Authors: Kiparissides C. , Vlachopoulos J. 
Published: December 2004

AbstractThe general equations describing the flow of Newtonian and non‐Newtonian fluids in the gap of two calender rolls were simplified by making use of the lubrication approximation. The resulting equations were solved by the finite element method. The results are in excellent agreement with existing analytical solutions for Newtonian fluids. New results were obtained for pressure, velocity profiles and sheet thickness of non‐Newtonian fluids for symmetric and asymmetric calendering (different roll diameters, different roll speeds). The solution of this problem demonstrated the great possibilities offered by the finite element method in solving Theological problems of practical significance, particularly whenever complicated wall boundaries or free surfaces are involved.
Rheological properties of incompatible blends of two elastomers
Authors: Shih C. K. 
Published: December 2004

AbstractMold flows and melt viscosities of an incompatible bi‐component EPDM and “Viton” fluoroelastormer system were examined. A marked reduction in the melt viscosities of either component was observed when a small amount of the other component was present. It was speculated that the phenomenon was a result of a slippage between the polymer and the coated capillary surface due to the presence of a minor amount of the incompatible polymer. Evidence is given to indicate that this effect cannot be accounted for using the “melt structural heterogeneity” mechanism proposed for a different system by Andtrianova.
Increase of adhesive bond strength through the mechanochemical creation of free radicals: I
Authors: Brenman M. , Lerchenthal Ch. H. 
Published: December 2004

AbstractA new technique for improving the strength of bonded joints between various materials and different adhesives is described. Increased strength was obtained by mechanical Surface Activation Beneath Reactive Adhesives (SABRA). This technique results in higher bond energies due to the creation of free radicals. The surfaces were activated by abrasion with emery paper in the presence of the adhesive itself (epoxy), or of some suitable primer such as methyl methacrylate, acrylonitrile (AN) or hydrogen sulfide gas. The effects of this technique were demonstrated by four different methods: 1) Improved wetting of standard epoxy or water drops on the treated surface. 2) Achievement of bond energies between primers and polymeric surfaces exceeding the energy of solution in solvents, which were revealed by attenuated total reflectance infrared. 3) The detection of free radicals created by bond scission during abrasion by means of diphenylpicryl hydrazyl, (DPPH), a free radical scavenger, monitored by spec‐trocolorimetry, 4) Destructive testing of single lap joint test Pieces, scarfed tube joints and pee) test samples. These experiments will be described in a second paper. The theoretical base of the new approach is supported by a tentative estimate of energies set free by mechanochemical creation of free radicals and the excess heat released during abrasion.
Thermoplastic urethane elastomers V. Compatible and incompatible blends with various polymers
Authors: Seefried C. G. , Koleske J. V. , Critchfield F. E. 
Published: December 2004

AbstractVarious blends over extended compositional ranges have beer, prepared for combinations of a thermoplastic urethane elastomer with polystyrene, a styrene‐acrylonitrile copolymer, a polyhydroxyether (Phenoxy A), and poly(vinyl ethyl ether). The thermoplastic urethane elastomer was based on a polycaprolactone diol of approximately 2100 number average molecular weight, 4,4′‐diphenylmethane diisocyanate and 1,4‐butanediol at a molar ratio of 1/2/1, respectively. At ambient temperature, the tensile properties of the blends typically are intermediate between the values of the two separate components. Characterizations of the dynamic mechanical properties of the blends show the relative degree of compatibility for the thermoplastic urethane elastomer and the respective polymers. Two separate glass transitions are obtained for blends of polystyrene and the styrene‐acrylonitrile copolymer with the thermoplastic urethane elastomer. This behavior demonstrates that these blend systems are incompatible. The blends of Phenoxy A and the thermoplastic urethane elastomer exhibit a single glass transition for which the temperature is dependent on the respective concentration of the components. These mixtures are considered to be compatible in nature.
The stress‐strain behavior of materials exhibiting andrade creep
Authors: Berry G. C. 
Published: December 2004

AbstractThe stress‐strain behavior of a material exhibiting Andrade creep (for which the creep compliance is linear in the cube‐root of time) has been calculated for loading at constant strain rate \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm \varepsilon}\limits^{\rm .} $\end{document} and at constant stress rate \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \sigma \limits^. $\end{document} for the limiting case of linear viscoelastic behavior and at constant \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \sigma \limits^. $\end{document} for one type of nonlinear viscoelastic response. The recoverable strain after the stress has been removed has also been calculated for these three cases. The results of the calculations are compared with experiment.
An extensiometer for molten plastics
Authors: Rhi‐Sausi Jorge , Dealy John 
Published: December 2004

AbstractA new rheometer has been developed to measure the extensional viscosity of molten thermoplastics at typical extrusion temperatures. It is at the same time versatile and easy to operate. One end of the test specimen is held in a fixed position by an oil‐cooled chimp mounted on the end of a force transducer. The other end of the specimen is held by, a moving, oil‐cooled chimp. The moving clamp is suspended from a carriage mounted on a ball nut which travels on a long lead screw. The lead screw is driven by an electric motor operating through a gear box, and its speed can be controlled to produce either a constant stress (creep) or a constant strain‐rate (stress growth) experiment. Experimental results have verified that in the “constant strain rate” mode the strain rate does rise rapidly to a constant level. Measurements on several polyethylene resins indicated that the extensional viscosity rises with strain rate at low strain rates.
Toughness and brittleness of plastics: A summary of an ACS/SPE symposium
Authors: Deanin Rudolph D. 
Published: December 2004

AbstractA recent and joint ACS/SPE symposium featured 40 papers on the fundamental mechanism of brittle fracture, low‐speed crazing and fracture, high‐speed impact mechanisms, fatigue failure, multi‐phase polymer systems, and reinforcing fibers. A survey of these papers indicates the present state of our knowledge in this field, and the rapid progress it is making toward the development of high‐performance plastic materials.
The rheology of suspensions of titanate fibers in polymer solution
Authors: Onogi Shigeharu , Mikami Yoichi , Matsumoto Takayoshi 
Published: December 2004

AbstractThe, Theological properties of suspensions of relatively small amounts of titanate fibers in polystyrene solution have been measured by means of a Weissenberg rheogoniometer. The titanate fibers employed have diameters smaller than 0.5 micron and aspect ratios higher than 40. It has been found that the rheological properties of the suspensions are markedly time dependent; the steady‐flow shearing stress increases with increasing time when the rate of shear is changed abruptly from an initial high value to a considerably lower final value. This behavior can be attributed to the re‐formation of a structure formed by the dispersed fibers and broken at higher shear rates. The dynamic storage modulus G′ also depends strongly upon the re‐formation of the structure. Although the structure reformation process under shear appears too complicated to be analyzed satisfactorily, an attempt has been made to generalize the experimental data with a simple equation.
The role of intercrystalline links in the environmental stress cracking of high density polyethylene
Authors: Frayer Paul D. , Tong Paul Po‐Luk , Dreher William W. 
Published: December 2004

AbstractResults of dynamic mechanical spectroscopy, infrared spectroscopy, and tensile stress‐strain data show that the non‐ionic surfactant Igepal CO‐630, often used as a stress cracking agent, and water are absorbed by high density polyethylene to cause an internal stress relaxation of the intercrystalline tie molecules. The resulting molecular rearrangements produce changes in both the crystalline and amorphous regions. Thus, a molecular mechanism is proposed for the long‐term aging process based on the results of accelerated aging in the presence of an environmental stress cracking agent.
Permeation and sorption in inhomogeneous polymer membranes
Authors: Frisch H. L. 
Published: December 2004

AbstractRestricting the discussion to isothermal transport of a single penetrant in a polymer sample, we define convection and diffusion. We distinguish carefully between diffusion in homogeneous and inhomogeneous samples. In the latter case, the diffusion flux is no longer directly proportional to the gradient of the concentration, i.e., Fick's first law does not hold. We point out, unless an external force responsible for convection can be identified, that diffusion with convection in a homogeneous medium is in many instances indistinguishable mathematically from diffusion in an inhomogeneous medium with microscopic inhomogeneities. Finally, we list a number of exact results available for permeation and sorption parameters for thin slab of a dilute inhomogeneous material. These parameters all yield the same value of the diffusion coefficient if the latter is constant. On the other hand, these parameters provide different functional information about the partition coefficient and diffusion coefficient for an inhomogeneous polymer‐penetrant system.
Chemorheological changes in crosslinked epoxy resins subjected to large strains
Authors: Katz Dov , Buchman Alisa 
Published: December 2004

AbstractChemorheological changes in epoxy resins subjected to large strains while heated were observed earlier, but the subject was not treated quantitatively. This paper describes the investigation of an epoxy resin—Epon 826, of known chemical, structure, crosslinked with two different amines. By means of a simple calibrated apparatus, the epoxide samples were subjected to large strains in a non‐oxidizing atmosphere and in air. They were heated to different temperatures for various times; the results were compared with data obtained from unstrained samples kept in otherwise the same conditions. The results show a linear‐logarithmic relation between the torsion modulus, G(10) and the time of applied strain at a certain temperature and also a linear relation between G(10), and 1/T°K, both above T(10). The results obtained in swelling experiments support the data from 10 sec torsional modulus vs temperature measurements. An increase in the amount of solubles and in Mc is observed on extending the time of heating. A clear difference in properties between the strained and unstrained samples, kept in otherwise the sane conditions, is observed and the contribution of the applied strain to chemorheology has been shown. Both systems of crosslinked Epon 826 showed the same general behavior, although the specific data were different.
The deep drawing of thermoplastics
Authors: Miles M. J. , Mills N. J. 
Published: December 2004

AbstractThe theory of deep drawing, which has been developed for metals, is examined critically for thermoplastics. Two special characteristics of thermoplastics, the strong orientation hardening after initial yielding and the ease of crack formation and growth, are shown to vitiate the usual correlation between the drawability of the sheet and the low strain plastic behavior of the material. Attempts to improve the limiting draw ratio of thermoplastics, by biaxially rolling sheet prior to forming, are shown to be effective only if the polymer does not craze easily under tensile stresses.
The examination of poly(5‐hexene‐2‐one sulfone) as a positive‐working photoresist
Authors: Himics R. J. , Ross D. L. 
Published: December 2004

AbstractA novel photoresist material is described, consisting of a copolymer of 5‐hexene‐2‐one and SO2, which performs with or without the addition of sensitizers. This photoresist forms non‐tacky films that adhere well to silicon oxide without requiring thermal treatment. They also have useful sensitivity, can be developed to form highly‐resolved images, are inert to conventional etchants, and are readily removed after etching. The synthesis, characterization, and a possible mechanism for photodegradation are presented.
A study of the photochemical reaction between poly(vinyl alcohol) and aqueous chromate ion
Authors: Lee Van Nice H. , Farlee Rodney 
Published: December 2004

AbstractThe photochemical reaction between poly(vinyl alcohol) (PVA) and chromate ion in aqueous solution has been studied by ultraviolet spectroscopy and electron paramagnetic resonance (EPR). The first step of the reaction appears to be formation of a PVA‐chromate ester. No further detectable chemical changes occur unless the ester is irradiated. Spectral sensitivity data indicate the reaction is initiated only by the chromate ester charge transfer absorptions at approximately 370 nm and 450 nm. EPR indicates an equilibrium concentration of Cr (V) during irradiation arid a decrease in concentration of Cr(V) following second order kinetics upon cessation of irradiation. The final reaction product is Cr (III) complexed with the hydroxyl groups of the PVA. The reaction rate is a function of pH between pH 12; however no detectable reaction occurred above pH 12. A mechanism is proposed for the PVA‐chromate photoreaction in solution.
Theoretical considerations on the sensitivities of electron beam resists
Authors: Tsuda Minoru , Oikawa Setsuko , Suzuki Akira 
Published: December 2004

AbstractA theoretical study has been carried out in order to explain the sensitivities of electron beam and X‐ray resists. A preliminary investigation reveals that the behavior of these resists, on irradiation by high energy radiation, may be considered to be the electronically‐excited species in the polymer. To elucidate the chemical reactions in the excited states the adiabatic potential curves are calculated by the INDO/S procedure, which considers all the valence electrons and all the singly excited electronic configurations. Polyethylene and polyisobutylene were chosen as representative of crosslinkable and degradable polymers, respectively, since there is a parallelism between the beam sensitivity of resists and the effects of high energy radiation on polymers. Polyisobutylene has many antibonding curves favorable for the main chain scission in the excited states and polyethylene does not except for one improbable state. It was concluded that degradability is explainable by the ease of bond fission in the excited states; the crosslinkability is considered to be nondegradable property.