bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of high‐strength/high‐modulus regenerated cellulose fibers from lyotropic mesophases
Authors: Gilbert R. D. , Hu Xuechao , Fornes R. E. 
Published: April 2003

AbstractCellulose triacetate (CTA) fibers were spun from a 35% (w/v) solution of CTA (molecular weight, 95,000) in trifluoroacetic acid (TFA)/CH2CL2 (60/40, v/v) using laboratory‐scale spinning equipment, an air gap, and cold MeOH as the coagulant. The resulting fibers, of large diameter (ca. 80 μm) were saponified with a variety of reagents. The regenerated cellulose fibers had tenacities and moduli as high as 1.6 and 50 GPa, respectively. The fiber properties did not show a dependence on which cellulose polymorph was present. It is suggestes that for highly oriented fibers, the cellulose molecular weight is the primary parameter that determines the strength and modulus. This emphasizes the advantages of using a lyotropic cellulosic mesophase which permits relatively low solution viscosities at high concentrations and high polymer molecular weights. © 1995 John Wiley & Sons, Inc.
Viscoelastic and elastic behavior of polypropylene and ethylene copolymer blends
Authors: Cassagnau P. , Espinasse I. , Michel A. 
Published: April 2003

AbstractThermorheological properties of an incompatible polymer blend of polypropylene inclusions dispersed in a ethylene copolymer matrix were discussed from the emulsion model developed by Palierne. Due to the different rheological behaviors with temperature of the two phases, such a system proved to be a judicious blend in order to consider the special cases of the model applications: (1) the two phases are viscoelastic liquids, (2) the dispersed phase is a solid elastic assimilated to rigid spheres in comparison with viscoelastic liquid behavior of the matrix, and (3) the two phases are elastic solids. At low frequencies, the rheological behavior of the blend was not correctly predicted by the model. So interactions other than hydrodynamics can exist in the intrafacial region, and physical entanglements between the chains of the two constituents leading to topological interactions may be assumed at the interphase. © 1995 John Wiley & Sons, Inc.
Synthesis and properties of methacrylonitrile–EPDM–2–vinylnaphthalene graft terpolymer
Authors: Lee Seung Wook , Park Duck Jei , Ha Chang Sik , Cho Won Jei 
Published: April 2003

AbstractThe graft terpolymer of methacrylonitrile (MAN) and 2‐vinylnaphthalene (2‐VN) onto ethylene‐propylene‐diene terpolymer (EPDM) was synthesized in toluene using benzoyl peroxide (BPO) as an initiator. The effects of EPDM content, mole ratio of 2‐VN to MAN, reaction time, reaction temperature, and initiator concentration on the graft copolymerization were examined. The synthesized graft terpolymer was identified by IR and 1H‐NMR spectroscopies. The light resistance, thermal stability, molecular weight, and tensile properties of the graft terpolymer were investigated by Fade‐o‐meter, thermogravimetric analysis, gel permeation chromatography (GPC), and a universal tensile machine (UTM). It was found that the light resistance and heat resistance as well as the tensile strength of the graft terpolymer are considerably better than those of the acrylonitrile‐butadiene‐styrene (ABS) terpolymer. © 1995 John Wiley & Sons, Inc.
Preparation and properties of new polycyclic aliphatic polyamides base on diamantane
Authors: Chern Yaw‐Terng , Fang Jea‐Shih , Chung Meng‐An 
Published: April 2003

AbstractA series of novel polycyclic aliphatic polyamides was synthesized by direct polycondensation of the 1,6‐diamantane dicarboxylic acid with various alicyclic diamines in N‐methyl–2–pyrrolidone (NMP) containing lithium chloride, using triphenyl phosphite and pyridine as a condensing agent. The polyamides had inherent viscosities of 0.33–0.49 dL/g. The glass transition temperatures of the these polyamides were in the range of 200–220°C, and the 5% weight loss temperatures were in the range were 290–319°C in nitrogen. © 1995 John Wiley & Sons, Inc.
Preparation of polyethyleneglycol (PEG) and cellulose acetate (CA) blend membranes and their gas permeabilities
Authors: Li Jintong , Nagai Kazukiyo , Nakagawa Tsutomu , Wang Shichang 
Published: April 2003

AbstractMiscible blend membranes containing 10 wt % PEG of low molecular weight 200, 600, 2000, and 6000, and 10 wt %, 20 wt %, 30 wt %, 40 wt %, 50 wt %, and 60 wt % of molecular weight 20,000 were prepared to investigate the effect of PEG on gas permeabilities and selectivities for CO2 over N2 and CH4. The permeabilities of CO2, H2, O2, CH4, and N2 were measured at temperatures from 30 to 80°C and pressures from 20 cmHg to 76 cmHg using a manometric permeation apparatus. It was determined that the blend membrane, which contained 10% PEG 20,000, exhibited higher permeability for CO2 and higher permselectivity for CO2 over N2 and CH4 than those of the membranes that contained 10% PEG of the molecular weight ranging from 200 to 6000. The high PEG 20,000 content blend membranes showed remarkable permeation properties such that the permeability coefficients of CO2 and the ideal separation factors for CO2 over N2 reached above 200 barrer and 22, respectively, at 70°C and 20 cmHg. Based on the data of gas permeability coefficients, time lags, and characterization of the membranes, it is proposed that the apparent solubility coefficients of all CA and PEG blend membranes for CO2 were lower than those of the CA membrane. However, almost all of the blend membranes containing PEG 20,000 showed higher apparent diffusivity coefficients for CO2, resulting in higher permeability coefficients of CO2 than those of the CA membrane. It is attributed to the high diffusivity selectivities of CA and PEG 20,000 blend membranes that their ideal separation factors for CO2 over N2 were higher than those of the CA membrane in the temperature range from 50 to 80°C, even though the ideal separation factors of all CA and PEG blend membranes for CO2 over CH4 became lower than those of the CA membrane over nearly the full temperature range from 30 to 80°C. © 1995 John Wiley & Sons, Inc.
Swelling characteristics of block order networks prepared by styrene‐ethylene/butylene ABA triblock copolymer and styrene homopolymer binary blends
Authors: Konstantakopoulos I. C. , Valkanas G. N. 
Published: April 2003

AbstractMixed networks based on polystyrene (PS) and styrene‐ethylene/butylene triblock copolymer (SEBS) binary blends were synthesized via a postpolymerization Friedel‐Crafts‐type reaction employing styrene units and a bis‐chloromethylated crosslinking agent. The swelling behavior of the produced gels was studied in relation to network densty, SEBS/PS mass ratio, and solubility parameter of the swelling media, in a range of aliphatic, chlorinated, and aromatic solvents. Swelling characteristics of the mixed macronets were found to differ markedly from those of pure homopolymer gels. Selective swelling was observed in three different regions in respect to the solvent solubility parameter, in contrast to pure PS networks where adsorption was favored in a single region of solvents. This phenomenon was found to depend primarily on the SEBS/PS constitution of gels, while the solvent holding capacity depended directly on the crosslinking density. © 1995 John Wiley & Sons, Inc.
Chemical etching of polyimide film
Authors: Lian Syh‐Ming , Chen Ker‐Ming , Lee Rong‐Jer , Pan Jing‐Pin , Hung Aina 
Published: April 2003

AbstractChemical etching rates of BPDA/PDA/ODA/BMI polyimide film by an alkaline etching solution with the presence of different kinds of etchants were studied by film‐thickness measurement and UV absorption spectroscopy of dispersible etching residue. The etching rate of polyimide film in alkaline ethylene diamine solution is highest among the etching solutions studied in the present experiment. If an external bias voltage was applied during etching, the etching rate was increased. The effects of temperature, solubility of the etchant, and ultrasonic vibration on etching rate are also discussed. The presence of a radical in the process of etching reveals that the etching reaction is a type of radical chain reaction. © 1995 John Wiley & Sons, Inc.
Miscibility of poly(vinyl acetate) and vinyl acetate‐ethylene copolymers with styrene‐acrylic acid and acrylate‐acrylic acid copolymers
Authors: Bott R. H. , Kuphal J. A. , Robeson L. M. , Sagl D. 
Published: April 2003

AbstractPoly(vinyl acetate) and vinyl acetate‐ethylene (VAE) copolymers compose one of the more important polymeric materials, widely employed in coating and adhesive applications. A new class of miscible polymer blends involving poly(vinyl acetate) and VAE with styrene‐acrylic acid and acrylate‐acrylic acid copolymers has been found. Experimental windows of miscibility as a function of the ethylene content for VAE copolymers and the acrylic acid content of the acrylate‐acrylic acid copolymers are observed (acrylate = methyl acrylate, ethyl acrylate, n‐butyl acrylate, and 2‐ethylhexyl acrylate). Employing well‐established analog heat of mixing measurements, predicted windows of miscibility were compared with experimental results. Fair qualitative agreement was observed and supported the hypothesis that specific rejection arguments can be employed to explain the observed miscibility. Failure to quantitatively predict miscibility based on the analog heat of mixing measurements may be due to the higher association tendencies of the model compounds relative to acrylic acid units in the high molecular weight polymers. No miscible combinations were found for methyl methacrylate‐acrylic acid copolymers or acrylate‐methacrylic acid copolymers in admixture with poly(vinyl acetate) or the VAE copolymers, thus indicating the sensitivity of phase behavior to minor structural changes. VAE (30 wt % ethylene) copolymers were also noted to be miscible with several polymers previously noted to be miscible with poly(vinyl acetate), namely, poly(vinylidene fluoride), poly(ethylene oxide), and nitrocellulose. © 1995 John Wiley & Sons, Inc.
Comparison of size distribution data from dynamic light scattering and size‐exclusion chromatography
Authors: Mrkviĉková L. , Porsch B. , Sundelöf L.‐O. 
Published: April 2003

AbstractThe intensity‐defined distribution functions of hydrodynamic radii of equivalent spheres, Rh, obtained from dynamic light‐scattering experiments using the CONTIN procedure via the Stokes formula were compared with distributions of gyration radii, Rg, determined by size‐exclusion chromatography. The number‐, weight‐, and intensity‐ (z)‐defined Rg distributions accessible from size‐exclusion chromatography experiments were calculated using the Flory‐Fox relation. Reliable ratios of average radii, Rg/Rh, for linear polystyrenes having narrow, broad, or bimodal molecular weight distributions were obtained in toluene. Care should be taken to utilize properly averaged experimental quantities. For instance, the CONTIN DLS data evaluation procedure yields the z‐average of the inverse of the hydrodynamic radius, 〈1/Rh〉z−1. © 1995 John Wiley & Sons, Inc.
Reactive processing of LLDPEs in corotating intermeshing twin‐screw extruder. I. Effect of peroxide treatment on polymer molecular structure
Authors: Lachtermacher Marly G. , Rudin Alfred 
Published: April 2003

AbstractCommercial ethylene‐octene linear low‐density polyethylene (LLDPE) polymers were reactively extruded with low levels of 2,5‐dimethyl‐2,5 di(t‐butylperoxy)hexane to modify their molecular structure and processing properties. Peroxide levels were kept low to avoid crosslinking. This article examines the effects of reactive extrusion in a corotating intermeshing extruder. Gel content analyses and examination of extruded thin tapes indicated that the products were gel‐free, but line‐broadening in high‐resolution 13C‐NMR spectra suggested that some crosslinking did occur. Molecular weight distributions were broadened toward higher molecular weights, as expected. SEC estimates of long‐chain branching in reacted polyethylenes were consistent with the results of 13C‐NMR analyses. Under our extrusion conditions, the products contained about one long branch per number‐average molecule. This result and data on changes in carbon‐carbon unsaturation indicate that the major chain extension mechanism is an end‐linking reaction between terminal vinyls or allylic radicals formed at chain ends and secondary radicals. Both types are produced by hydrogen abstraction on the LLDPE. All long branches originated at tertiary branch points. Changes in thermal behavior, as measured by DSC analyses, paralleled those observed by temperature‐rising elution fractionation (TREF). SEC molecular weight measurements and long‐branch determinations by SEC and 13C‐NMR can be used to quantify the effects of peroxide treatment on the molecular structure of polyethylenes. DSC and TREF techniques, however, appear to be more sensitive than are SEC or NMR. Relatively minor variations in the degree of mixing and temperature control during reactive extrusion have noticeable effects on the molecular structures of the peroxide‐treated LLDPEs. © 1995 John Wiley & Sons, Inc.
Continuous vapor phase polymerization of pyrrole. I. Electrically conductive composite fiber of polypyrrole with poly(p‐phenylene terephthalamide)
Authors: Xu Chaochou , Wang Peng , Bi Xiantong 
Published: April 2003

AbstractElectrically conductive polypyrrole (PPy)/poly(p‐phenylene terephthalamide) (PPTA) composite fibers have been prepared by continuous vapor phase polymerization at a speed of 0.5 ∼ 1.5 m/min. The main parameters have been examined, and the conducting fibers with the best properties of electrical conductivity 0.68 s/cm, tensile strength 2731 N/mm2, and the elongation at break 4.8% were obtained by using FeCl3 · 6H2O as the oxidizing agent. The results of elemental analysis, wide‐angle X‐ray diffraction analysis and SEM of the composite fibers are also reported. © 1995 John Wiley & Sons, Inc.
Sulfur vulcanization of polyisoprene accelerated by benzothiazole derivatives. I. Comparison of sulfur and 2‐mercaptobenzothiazole accelerated reactions
Authors: Gradwell M. H. S. , Mcgill W. J. 
Published: April 2003

AbstractPolyisoprene compounds with sulfur and with sulfur and 2‐mercaptobenzothiazole (MBT) were vulcanized by heating in a differential scanning calorimeter (DSC) at a programmed rate. The reaction was stopped at various temperatures along the thermogram and the product analyzed by determining the crosslink density and crosslink type, and by determining the amount of extractable curatives and soluble reaction products by high‐performance liquid chromatography. DSC cure curves and plots of crosslink density and extractable sulfur vs. temperature for the unaccelerated and MBT accelerated compounds can be made to coincide by shifting them along the temperature axis. It is suggested that MBT accelerated sulfur vulcanization occurs by the same mechanism as unaccelerated sulfur vulcanization, with SH+ ions from MBT adding across the carbon–carbon double bond, thus increasing the rate at which the reaction is initiated. © 1995 John Wiley & Sons, Inc.
Nitrogen solubilities in low‐density polyethylene at high temperatures and high pressures
Authors: Lee James G. , Flumerfelt Raymond W. 
Published: April 2003

AbstractAn apparatus for the determination of the solubility of gases in polymers at high pressure and high temperature is described. The solubilities of nitrogen in low‐density polyethylene (PE800E) at 394–450 K at pressures between 10 and 125 atm are reported. Empirical correlations are obtained which represent the Flory–Huggins interaction parameter χ, solubility coefficient KH, and activity coefficient of dissolved gas Ω2 as functions of temperature and pressure for the above system. © 1995 John Wiley & Sons, Inc.
Development of poly(vinyl alcohol) hydrogel for waste water cleaning. II. Treatment ofN,N‐dimethylformamide in waste water with poly(vinyl alcohol) gel with immobilized microorganisms
Authors: Okazaki Masaki , Hamada Tosihiro , Fujii Hiroaki , Kusudo Osamu , Mizobe Akio , Matsuzawa Shuji 
Published: April 2003

AbstractThe activated sludge that had been sufficiently cultivated with DMF‐containing waste water was entrapped and immobilized in spherical poly(vinyl alcohol) (PVA) hydrogel particles. Features of numbers and distribution of bacteria in the resultant PVA gel were estimated. The DMF‐decomposing bacteria namedBacillus cereusD‐1 was isolated. Several morphological and physiological responses of the bacteria were revealed. Spherical PVA gel with the DMF‐decomposing bacteria prepared through of freezing and thawing was tested for treatment of DMF‐containing effluent. Test results have shown the ability of stable operation and maintenance at the same capacity of 1 kg/m3/day by both a basic study and a bench plant test. © 1995 John Wiley & Sons, Inc.
Cure and physical properties of thermoplastic modified epoxy resins based on polyethersulfone
Authors: Mackinnon Alexander J. , Jenkins Stephen D. , Mcgrail Patrick T. , Pethrick Richard A. 
Published: April 2003

AbstractDielectric, mechanical, thermal, rheological, and electron microscopy measurements are reported for five series of thermoplastic modified amine cured epoxy resin systems. The epoxy and thermoplastic components have been systematically changed to investigate the factors affecting the phase separation process. Data reported cover both changes in the physical properties occurring during cure and also of the final cured matrix. Dielectric data obtained from fully cured materials exhibits a Maxwell–Wagner–Sillers relaxation process characteristic of a phase separated morphology. Correlation of dielectric relaxation and electron microscopy data indicates that the phase structure changes with the thermoplastic content and composition of the epoxy phase. The mechanical properties change significantly at about 20–25% (w/w) of incorporated thermoplastic, coincident with the formation of a cocontinuous phase morphology. © 1995 John Wiley & Sons, Inc.
Electrical behavior of polycarbonate doped with nickel chloride
Authors: Amin M. , Mounir M. , Darwish K. A. , Elez M. Abu 
Published: April 2003

AbstractThe dc electrical conductivity (σ) and permittivity (ε′) of polycarbonate (PC) discs doped with different concentrations of NiCl2 are studied. Both (σ) and (ε′) increase with increasing the concentration of NiCl2, with a maximum value at 30 wt %. The activation energies for pure and doped PC are 0.49 and 0.53 eV, respectively. The increase in the electrical conductivity with increasing NiCl2 concentration is attributed to the formation of chargetransfer complexes (CTC); the increase in ε′ may be due to the rise in the interfacial polarization which results from the increase in boundaries between PC and NiCl2 phases. The currents in PC discs, both pure and doped with NiCl2, in the high‐field region are attributed to space charge limited conduction. The time dependence of conduction current before and after reversal of applied voltage is also investigated. Some parameters such as the density of mobile ions and their drift mobilities are estimated. © 1995 John Wiley & Sons, Inc.
Vascular endothelial growth factor: A regulator of vascular morphogenesis in the Japanese quail embryo
Authors: Finkelstein Eric B. , Poole Thomas J. 
Published: April 2003

AbstractExperiments in mouse embryos indicate that a critical level of VEGF is required for normal vascular development, as mice lacking a single VEGF allele die at midgestation. Thus VEGF concentration may be a determinant of the size and location of major blood vessels during formation of the primary capillary plexus. Ectopic VEGF delivery was used to examine the effect of VEGF concentration on early vascular patterning in the quail embryo. VEGF was delivered by implanting VEGF‐soaked heparin chromatography beads at three rostral‐caudal locations in embryos with six somite pairs, which allowed us to study the effect of VEGF on different cellular activities. Ectopic VEGF resulted in significant changes in the vascular pattern at three rostral‐caudal levels. Quantitation demonstrated an increased vascularity in the area of the implanted VEGF bead compared to the vascular pattern of embryos with control beads. Areas lateral to the dorsal aortae that are normally avascular became vascularized, and there was an apparent fusion between the dorsal aorta and lateral capillary plexus. Anat Rec Part A 272A:403–414, 2003. © 2003 Wiley‐Liss, Inc.
Multimode software defined radio receiver using direct conversion and low‐IF principle: Implementation and evaluation
Authors: Yoshida Hiroshi , Kato Takayuki , Tomizawa Takeshi , Otaka Syoji , Tsurumi Hiroshi 
Published: April 2003

AbstractIn recent years, software defined radio has attracted attention as radio with features that can be freely changed by software. The authors have previously proposed a concept for a receiver that converts the entire bandwidth of a desired system to digital signals and selects the signals of the desired channel in the digital stage. In addition, they have applied this concept to propose a basic configuration of a software defined radio using the direct conversion and low intermediate frequency (low‐IF) principle. In this paper, the authors investigated a specific implementation of the previously proposed wideband analog stage using the direct conversion and low‐IF principle and digital stage having an image rejection function and evaluated this implementation through experiments using the 1.5‐ and 1.9‐GHz bands. The results showed that a 10‐MHz wideband was implemented for the bandwidth and that at least 25 dB was obtained for the image rejection ratio by using the direct conversion principle and at least 61 dB was obtained by using the low‐IF principle. In addition, the authors performed the evaluation using the entire receiver and confirmed that the implementation was error free for multiple modulation modes. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(10): 55–65, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10004
Reliable multicast using adaptive caching
Authors: Tajima Yoshitake , Morikawa Hiroyuki , Aoyama Tomonori 
Published: April 2003

AbstractIn this paper, we present a detailed description of the Reliable Multicast using Adaptive Caching (RMAC) system and protocol, and describe its performance evaluation. From the idea that support based on functional processing in the network is essential to efficiently perform reliable multicast, routers that process the RMAC protocol are introduced by RMAC. RMAC can improve retransmission efficiency by packet caching and retransmission at the routers. The required cache size can be decreased by distributing the caching among the routers to adapt to the congestion. The performance evaluation by a simulation showed that RMAC has lower recovery latency compared to conventional techniques and improved scalability with respect to the number of receivers. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(10): 89–99, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1179
A nonscan DFT method for RTL circuits based on fixed‐control testability
Authors: Nagai Shintaro , Wada Hiroki , Ohtake Satoshi , Fujiwara Hideo 
Published: April 2003

AbstractIn this paper, we will newly define the fixed‐control testability as the property of the data paths for which the hierarchical test generation is easy; and based on it we will propose a design for testability (DFT) method for register transfer level (RTL) circuits. In the proposed method, since it is based on the hierarchical test generation using combinational test generation method and nonscan design, the test generation time and test execution time can be shortened drastically compared to the full‐scan design method, and the test at real operation speed (at‐speed test) is possible; and the complete fault detection efficiency can be guaranteed. Moreover, the effectiveness of the proposed method will be shown by experiments using benchmark circuits. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(10): 43–55, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10119