bluuebunny/crossref_metadata_2025_split huggingface dataset:
A high resolution negative working resist, LMR‐UV, for g‐ and i‐line lithography
Authors: Yamashita Yoshio , Jinbo Hideyuki , Kawazu Ryuji , Asano Takateru , Umehara Hiroshi 
Published: May 2005

AbstractLMR‐UV (“low molecular weight resist for uv lithography”), a naphthoquinone‐diazide sulfonic acid ester of a novolak resin, is a negative working resist. The mechanism of insolubilization of LMR‐UV is based on the facts that the naphthoquinone‐diazide moiety is decomposed to indenecarboxylic acid (polar compound) by photolysis upon UV irradiation and that the irradiated resist film insolubilizes in a non‐polar developer. LMR‐UV reliably forms 0.6 μm lines and spaces over a reflective substrate with steps by using a g‐line stepper having a 0.35 NA lens. 0.6 μm‐wide aluminum patterns over topography are obtained by use of g‐line exposure and reactive ion etching. By use of an i‐line aligner (NA = 0.42), LMR‐UV resolves 0.25 μm space patterns with overhang profiles. The profiles are due to the large absorption coefficient of 3.8 μm−1. 0.3 μm wide aluminum patterns are formed by i‐line exposure and lift‐off metallization.
Effect of drying conditions on the glass transition of poly(acrylic acid)
Authors: Park Jung‐Ki , Kim Dong‐Won , Kim Chul‐Hwan , Maeng Ki‐Suk , Hwang Taek‐Sung , Kim Young‐Chul 
Published: May 2005

AbstractSystematic changes of drying conditions of poly(acrylic acid) were tested to study their effect on the glass transition of the material. The materials were synthesized in two different mediums of water and benzene, respectively. The glass transition temperatures of the samples were determined by thermal analysis using DSC. The samples were also characterized by IR spectra. The glass transition of poly(acrylic acid) was found to be significantly dependent on the drying conditions and also dependent on the medium in which poly(acrylic acid) was prepared. The anhydride formation in poly(acrylic acid) was increased as the drying temperature was raised, resulting in the increase of the glass transition temperature. The “bound” water involved in the preparation of poly(acrylic acid) in water medium could affect significantly the glass transition of the sample. A significant discrepancy in the previously reported values of the glass transition temperature of poly(acrylic acid) seems to be due to the differences in the drying conditions of the materials.
Determination of unblended chain dynamic parameters of a polar discontinuous phase in an immiscible polymer blend
Authors: Havriliak S. , Banhegyi G. , Karasz F. 
Published: May 2005

AbstractA method is described by which the relaxation characteristics of a polar polymer in an included phase of an immiscible polymeric blend can be determined from those of the composite. The necessary prerequisite is that the relaxation regions of the matrix and of the dispersed phase do not overlap. First, the dynamic relaxation data of the composite is fitted to the Havriliak‐Negami function using a multi‐response fitting method. Next, the relaxation function for the included phase is determined using composite mixing equations and the data for the pure matrix. This method is demonstrated for dielectric data on a polypropylene/polyurethane (PP/PUR) composite containing 20 wt% polar additive. The resulting unblended relaxation function parameters of PUR are discussed and compared to other unblended PUR literature data. Blending PUR with PP did not change the shape of the relaxation process, did shift the maximum frequency by about half a decade, and significantly reduced the limiting values of the dielectric constants.
Studies on a diphenylether modified poly(phenyl‐1,4, phenylene terephthalate) liquid crystalline polymer and its blends with polycarbonate and polysulfone
Authors: Skovby M. H. B. , Kops J. , Weiss R. A. 
Published: May 2005

AbstractBlends of a thermotropic liquid crystalline polymer, LCP, (4,4′‐dicarboxy diphenyl ether modified poly(phenyl‐1,4‐phenylene terephthalate)) with polycarbonate and polysulfone were prepared and characterized with respect to their thermal properties, viscoelastic behavior, processability and mechanical properties. The processability of the thermoplastics was significantly improved by the addition of small amounts of LCP. This was also reflected by decreases in the steady shear viscosities, though the dynamic complex viscosities of the blends were generally similar or higher than those of the individual component polymers. Composite fibers were spun from the blends and the tensile moduli and strengths were consistent with a morphology of highly oriented LCP microfibrils with high aspect ratios dispersed in the thermoplastic fiber. The properties increased with increasing draw ratio.
Ultrasonic velocity and attenuation of polymeric solids under oscillatory deformation. III: Drawn films of high density and linear low density polyethylene and their blends
Authors: Nitta Koh‐Hei , Tanaka Akira 
Published: May 2005

AbstractViscoelastic nonlinearity was examined on uniaxially drawn films of high density and linear low density polyethylenes and their blends using dynamic ultrasonic measurements. It was found that nonlinearity due to plastic deformations, such as slippage and dislocations, occurs in the fibrous structures. Plastic deformations were different from those in corresponding undrawn films. For undrawn films, the formation and/or deformation of crystal defects and voids were caused by the disruption of spherulitic structures. Nonlinearity was smaller for drawn films than for undrawn films, suggesting that the superstructure of drawn films is more uniform and more stable for mechanical deformations.
Graft copolymerization of gelatin with poly(methyl methacrylate) in aqueous medium
Authors: Roy Papia , Kumar Anil 
Published: May 2005

AbstractThe grafting of poly(methyl methacrylate) onto gelatin in aqueous medium has been studied experimentally. The polymerization system is heterogeneous and the temperature and the initial concentration of gelatin charged in the reactor have been found to be extremely important. It is found that the amount of graft polymer increases rapidly and the formation of homopolymers is suppressed for large times. The predominantly graft polymer for the large times is essentially free from homopolymers and needs no separation. A theoretical model has been proposed which accounts for the heterogeneity in the reaction mass. The numerical solution of mass balance equations and its validation against experimental data suggests that graft copolymers react at the waterdroplet interphase at considerably higher rate.
Elastic‐plastic analysis of the deformation mechanism of PP‐EPDM thermoplastic elastomer: Origin of rubber elasticity
Authors: Kikuchi Yutaka , Fukui Takayuki , Okada Tetsuo , Inoue Takashi 
Published: May 2005

AbstractPolyolefinic thermoplastic elastomer (TPE) is a two‐phase material in which cured EPDM (ethylene‐propylene‐diene rubber) particles are densely dispersed in a PP (polypropylene) matrix. It can be melt‐processed at high temperatures and behaves like a vulcanized rubber at ambient temperature. The question is on its strain recovery, i.e., why the TPE can shrink back from the highly deformed states, even though the matrix consists of the ductile polymer. We constructed a two‐dimensional model with four rubber inclusions in ductile matrix and carried out the elastic‐plastic analysis on the deformation mechanism of the two‐phase system by FEM (finite element method). FEM analysis revealed that, even at the highly deformed states at which almost the whole matrix has been yielded by the stress concentration, the ligament matrix between rubber inclusions in the stretching direction is locally preserved within an elastic limit and it acts as an “in‐situ formed adhesive” for interconnecting rubber particles. It will provide a key mechanism of the strain recovery in the two‐phase system.
Effect of ultrasonic waves on foam extrusion
Authors: Isayev A. I. , Mandelbaum S. 
Published: May 2005

AbstractThe effect of ultrasonic waves upon foam extrusion has been investigated by using a special die attached to an extruder. The die consists of a special ultrasonic horn, having a circular channel, that vibrates at 20 KHz. Various ultrasonic amplitudes and flow rates were employed during extrusion of a foamed polystyrene. Ultrasonic waves were found to affect both die pressure as well as physical and mechanical properties of the foam. Increases in the amplitude of the ultrasonic waves resulted in a decrease of the pressure at the die entrance. The density of the foam was found to increase with an increase of the amplitude and a decrease of the flow rate. Extrudate swell was found to decrease with an increase in the amplitude. Ultrasonic waves also influenced cell size and distribution in extruded samples: increases in amplitude resulted in reduced cell size and in narrowing their distribution. These effects are likely caused by break up of large cells or by disruption of coalescence of small cells. The tensile strength and Young's modulus of samples of extruded foam were found to increase with ultrasonic treatment. A unique correlation of these mechanical properties with the density of the foam was established.
The permeability and compressibility of aligned and cross‐plied carbon fiber beds during processing of composites
Authors: Lam R. C. , Kardos J. L. 
Published: May 2005

AbstractTwo of the most important input parameters needed to simulate the processing of continuous fiber laminated composites are the fiber bed permeability and the portion of the autoclave load borne by the consolidating fiber network (compressibility). In this study we have experimentally examined how both these parameter change with resin volume fraction as pressure is applied and consolidation proceeds. For a unidirectional fiber bed, the Kozeny‐Carman equation can be used to predict both the transverse (perpendicular to the laminate plies) permeability (Kozeny constant, K′z = 11) and the axial (parallel to the fibers) permeability (Kozeny constant, K′X = 0.57). The axial permeability was found to be dependent on the surface tension of the permeant. For a unidirectionally aligned fiber, the measured transverse permeabilities varied from 1.1 × 10−10 cm2 to 12. × 10−9 cm2 while the axial values varied from 2.1 × 10−9 to 4.4 × 10−8 cm2 for a liquid volume fraction range of 0.25 to 0.5. Axial permeability measurements indicate that the permeability decreases with increasing off‐axis angle × (measured from the laminate axial direction). The off‐axis permeability behavior can be described by a modified Kozeny‐Carman equation. The fiber network compressibility can be described with a logarithmic relation which has been found valid for a large number of consolidated soils.
Pultruded fiber reinforced thermoplastic poly(methyl methacrylate) composites. Part II: Mechanical and thermal properties
Authors: Ma Chen‐Chi M. , Chen Chin‐Hsing 
Published: May 2005

AbstractA novel process has been developed to manufacture poly(methyl methacrylate) (PMMA) pultruded parts. The mechanical and dynamic mechanical properties, environmental effects, postformability of pultruded composites and properties of various fiber (glass, carbon and Kevlar 49 aramid fiber) reinforced PMMA composites have been studied. Results show that the mechanical and thermal properties (i.e. tensile strength, flexural strength and modulus, impact strength and HDT) increase with fiber content. Kevlar fiber/PMMA composites possess the highest impact strength and HDT, while carbon fiber/PMMA composites show the highest tensile strength, tensile and flexural modulus, and glass fiber/PMMA composites show the highest flexural strength. Experimental tensile strengths of all composites except carbon fiber/PMMA composites follow the rule of mixtures. The deviation of carbon fiber/PMMA composite is due to the fiber breakage during processing. Pultruded glass fiber reinforced PMMA composites exhibit good weather resistance. They can be postformed by thermoforming, and mechanical properties can be improved by postforming. The dynamic shear storage modulus (G′) of pultruded glass fiber reinforced PMMA composites increased with decreasing pulling rate, and G′ was higher than that of pultruded Nylon 6 and polyester composites.
Studies on the theory of single screw plasticating extrusion. Part I: A new experimental method for extrusion
Authors: Zhu Fuhua , Chen Liqin 
Published: May 2005

AbstractAn extruder specially designed for the study of the single‐screw plasticating extrusion process was constructed. Its barrel is equipped with glass windows which are located on both sides of it so that the full process of plasticating extrusion, solid conveying, melting, and melt conveying, can be clearly observed and recorded with photos and video recordings through the transparent windows. The solid profile X/W, the velocity of the solid bed Vsz, the forming positions of the upper melt film and the melt pool, and the position at which the break‐up of solid bed occurs, was easily determined with good accuracy. Many dynamic characters of the plasticating extrusion, such as the non‐plug solid conveying, the process of the break‐up of the solid bed and the disappearance of the, broken pieces of solid, were also observed in the experiments.
Studies on the theory of single screw plasticating extrusion. Part II: Non‐plug flow solid conveying
Authors: Fang Shizeng , Chen Liqin , Zhu Fuhua 
Published: May 2005

AbstractA non‐plug solid conveying theory for plasticating extrusion is proposed in this paper. The polymer granules are treated as‐bulk pellets which move down the screw channel at different speeds, rather than as a plug which never experiences deformation during extrusion. The pellets system is considered as a linear elastic system, and can only resist compressive forces but riot tensile forces. Based on elastic mechanics and virtual work principles, a mathematical model for non‐plug solid conveying is proposed. Finite element method (FEM) is used to determine the relationships between internal stress and velocity profiles of the pellets in the screw channel, the internal stress states at any point in the screw channel, etc. The prediction also proved the existence of the optimum depth of the screw channel and the optimum helix angle of the screw. Most of the experiments have been carried out on an extruder with glass windows it its barrel. The experiments confirm the validity of the theory.
Modeling of the impregnation process during resin transfer molding
Authors: Chan Albert W. , Hwang Sun‐Tak 
Published: May 2005

AbstractA model has developed for simulating isothermal mold filling during resin transfer molding (RTM) of polymeric composites. The model takes into account the anisotropic nature of the fibrous reinforcement and change in viscosity of the polymer resin as a result of chemical reaction. The flow of impregnating resin through the fibrous network is described in terms of Darcy's law. The differential equations in the model are solved numerically using the finite element technique. The Galerkin finite element method is used for obtaining the pressure distribution. A characteristics based method is used to solve the non‐linear hyperbolic mass balance equation. The finite element formulation facilitates computations involving the motion of the polymer resin front characterized by a free surface flow phenomenon.
Thermal stress induced damage in a thermoplastic matrix material for advanced composites
Authors: Adams Mary Elizabeth , Campbell Gregory A. , Cohen Arie 
Published: May 2005

AbstractIn this paper, we analyze the basic physics of residual stress development during cooling of thermoplastic composite matrix materials. The analytical model presented here examines development of the stress field during cooling off a cylinder of thermoplastic matrix material. The residual stress field predicted by the model is compared to observations of the differences in microstructure of polymeric materials with different processing histories. The results of the investigation indicate that changes in the matrix related to processing conditions can contribute to damage formation in composites.
Influence of maleic anhydride as a coupling agent on the performance of wood fiber‐polystyrene composites
Authors: Maldas D. , Kokta B. V. 
Published: May 2005

AbstractThe lack of polar groups in thermoplastics (e.g., in polystyrene) provides low adhesion with cellulosic fibers. To improve compatibility between reinforcement and matrix, maleic anhydride (MA) was selected as a coupling agent for wood fiber‐filled polystyrene composites. In general, the mechanical properties improved along with increased concentrations of MA, initiator (e.g., benzoyl peroxide) and wood fiber up to a certain limit and then decreased. The concentrations of MA and fiber which produced maximum improvements in the mechanical properties varied according to wood species, pulping techniques and type of polystyrene. Moreover, properties were further enhanced when another coupling agent (e.g., isocyanate) was used in addition to the MA.
Reinforcing high density polyethylene with cellulosic fibers. I: The effect of additives on fiber dispersion and mechanical properties
Authors: Raj R. G. , Kokta B. V. 
Published: May 2005

AbstractHigh density polyethylene (HDPE) was reinforced with 0‐40 wt% of wood flour (aspen). The effects of: stearic acid, mineral oil, maleated polyethylene wax, and sodium silicate on the tensile and impact strength of the composite were studied. The comparison of tensile properties of the composites showed that the addition of maleated polyethylene wax produced a significant increase in tensile strength, with the increase in filler concentration, while the tensile modulus remained relatively unaffected. Microscopic studies of the composites indicate a better dispersion of the fibers in the polymer matrix when stearic acid was used.
Computer simulations of crystallinity gradients developed in injection molding of slowly crystallizing polymers
Authors: Hsiung C. M. , Cakmak M. 
Published: May 2005

AbstractA model is developed to simulate the crystallinity gradients developed in injection molding of slowly crystallizing polymers. In this model, effects of nonisothermal and stress‐induced crystallization kinetics are taken into account through phenomenological relationships. Computer simulations included calculations of the temperature, velocity, and pressure distributions as well as two dimensional crystallinity distributions in the final products. In addition, effects of various processing conditions: mold temperature, injection flow rate, and holding time are also included in the calculations. The crystallinity gradients obtained through computer simulations agree with the experimental results obtained with poly (p‐phenylene sulfide) under a variety of processing conditions.
Development of cracks in injection moldings of poly (2,6‐dimethyl‐1, 4 phenylene ether)
Authors: Wagner Alan H. , Kalyon Dilhan M. 
Published: May 2005

AbstractCracks in injection molded articles adversely affect their appearance as well as their ultimate properties. In this study, we have investigated the spontaneous development of cracks in samples molded from an engineering plastic in the absence of external loading. The specimens of a well characterized poly(2,6‐dimethyl‐1,4 phenylene ether), PPE, were injection molded employing a 40t Van Dorn injection molding machine and industrial practices. The initiation and development of cracks in the molded articles were monitored for a period of eighty weeks. The presence and the frequency of the cracks were found to depend on the operating conditions employed during the molding, the shape of the cavity, the presence of Irregularities at the mold surface, and the particular location observed. The results were elucidated under the light of the results of microstructural analyses including residual stress and birefringence distributions on both compression and injection molded specimens of the engineering plastic.
Impact response of composite laminates with a hemispherical indenter
Authors: Pang S. S. , Zhao Y. , Yang C. , Griffin S. A. 
Published: May 2005

AbstractA model for predicting the contact duration, force, indentation, and displacement under impact has been developed for impact of a composite laminated plate with a hemispherical indenter. The governing equations were first proposed and then solved with the initial conditions along with the peak force condition. An expression forr each parameter has been obtained in a simple expression through straightforward derivation. Both static and dynamic tests have been conducted. Ten impact tests were conducted using a weight drop tower tester. Comparison between the, model predictions and the experimental data on the impact duration and impulse are provided, and were found to be within 14% for all tests involved. Comparison of the impact force‐history also shows good accord.
Styrene maleic anhydride and styrene glycidyl methacrylate copolymers as in situ reactive compatibilizers of polystyrene/nylon 6,6 blends
Authors: Chang Feng‐Chih , Hwu Yih‐Chyun 
Published: May 2005

AbstractThe reactive type copolymers styrene maleic, anhydride (SMA) and styrene glycidyl methacrylate (SG) are used as in situ compatibilizers in polyblends of polystyrene (PS) and nylon 6, 6 (N66). Both copolymers can react with N66 to form copolymers as effective compatibilizers to reduce interfacial tension and increase phase adhesion. However, the toughness of the compatibilized blends is significantly lower than of the corresponding noncompatibilized blends. Only a small fraction of SMA is actually reacted in a typical melt blending, and SG copolymer seems to be more reactive than SMA. The unreacted copolymers are expected to be distributed mostly in the PS phase because of their structural similarity. The reacted copolymers are not exclusively distributed along the interface; some may distribute in both matrices. SMA is known as a very brittle polymer, and the way it is distributed can greatly influence the toughness of the resulting blends. PS is also very brittle relative to N66, and moreover a high amount of SMA in the N66 phase is detrimental since N66 is responsible for the toughness of PS/N66 blends. The better compatibilized blends have the tendency to bring more SMA and reacted SMA into the N66 phase. The relative detrimental effect on the inherent toughness of N66 is much more severe than in case of PS, if they contain the same amount of SMA. This study demonstrates that polyblends with good compatibilizers do not guarantee toughness improvement. The way the compatibilizers affect the inherent properties of the matrix needs also to be taken into consideration.
Application of the Flory‐Huggins theory to the system chloroform‐polystyrene‐butadiene rubber
Authors: Geveke D. J. , Danner R. P. 
Published: May 2005

AbstractAccording to the Flory‐Huggins theory for polymer blends, the polymerpolymer interaction parameter, χ23, must be positive for incompatible polymers. Previous studies of the incompatible ternary system chloroform‐polystyrerne‐butadiene rubber yielded negative values of χ23 using a solution method based on the Flory‐Huggins theory with the chloroform‐butadiene rubber interaction parameter used as input. An alternate solution method using the chloroform‐polystyrene interaction parameter as input has been used to obtain positive values of χ23 for this incompatible system. This variation in results indicates that the interaction parameters obtained using the Flory‐Huggins theory are not physically meaningful. They are, however, useful as correlating parameters. Both sets of results, although quite different, are shown to correlate the experimental data identically well. In addition, the appropriate equations are presented for the case where one of the solvent‐polymer interaction parameters is concentration dependent.