bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ionic conductivity of hybrid films based on polyacrylonitrile and their battery application
Authors: Watanabe Masayoshi , Kanba Motoi , Nagaoka Katsuro , Shinohara Isao 
Published: April 2003

AbstractThe alternate current (AC) and direct current (DC) ionic conductivity of hybrid films composed of polyacrylonitrile (PAN), lithium perchlorate (LiClO4), and a plasticizer was studied. Three kinds of the plasticizer [ethylene carbonate (EC), propylene carbonate (PC), N,N‐dimethylformamide (DMF)] were used. Suitability of these hybrid films for lithium battery was investigated. The AC conductivity, which represents bulk ionic conductivity, was dependent on the component and the composition of the hybrid films, ranging from 10−4−10−8 Scm−1. The AC conductivity was mainly determined by the molar ratio of [plasticizer]/[LiClO4] in the hybrid films and increased with the increase in this ratio. The effect of the plasticizer on the enhancement in the AC conductivity was in the following order. DMF>EC>PC. The hybrid films with both electrodes of lithium showed the stable DC conductivity of about 1/10 of the AC conductivity, except for the hybrid films containing DMF. The hybrid films were found to be effective as a lithium ionic conductor. The galvanic cell. Li/sample/MnO2, at the discharge current density of 90 μA/cm2 showed the stable electromotive force of about 3 V for 70 h.
Separation of proteins by polymeric adsorbents containing azobenzene moiety as a ligand
Authors: Ishihara Kazuhiko , Kato Shinji , Shinohara Isao 
Published: April 2003

AbstractPolymeric adsorbents containing an azobenzene moiety as a ligand were prepared, and the photoinduced adsorption behavior of proteins to the adsorbent was studied. This method regulates by light the adsorption/desorption of proteins in hydrophobic chromatography. In the dark, the amount of protein adsorbed onto the adsorbent increased with increasing hydrophobicity of either adsorbent or protein. On irradiation with UV light, the amount of protein adsorbed decreased. Such a photoinduced change of the adsorption of protein was considered to be caused by the change of the hydrophobic interaction between the adsorbent and the protein due to the photoisomerization of the azobenzene moiety accompanying the polarity change of the adsorbent. It is also found that the desorption of protein was dependent on the balance of the hydrophobicity between the adsorbents and proteins. When column chromatography was carried out, the proteins were adsorbed in the dark and could be eluted after photoirradiation, with water as the single solvent. Furthermore, mixture of proteins could be separated by using a hydrophobic gradient column which was constituted by two polymeric adsorbents having different hydrophobicity.
Effect of particulate fillers on short jute fiber‐reinforced natural rubber composites
Authors: Murty V. M. , De S. K. 
Published: April 2003

AbstractThe effect of carbon black on the processing characteristics and physical properties of jute fiber‐reinforced composites and the role of silica and carbon black in promoting the adhesion between jute fiber and natural rubber have been studied. It was found that presence of silica is not essential to develop adhesion between fiber and rubber in the presence of carbon black. However, silica and carbon black can improve adhesion by minimizing the resin formation and controlling it to a low molecular weight species. Processing properties like green strength and mill shrinkage are improved by the addition of fiber. Carbon black does not affect mill shrinkage, but improves the green strength. Breakage of jute fiber during mixing is severe, but the extent of breakage is not affected by the presence of carbon black. The minimum loading of fiber to achieve reinforcement is reduced in the presence of carbon black. It was also found that the presence of clay in jute fiber rubber composites impairs the properties. Scanning electron microscopy (SEM) has been used to assess the failure criteria.
A heat and mass transfer study—analysis of continuous processes for the coloration of polyester fabric. II. Modelling and characteristics of the (polyester) fabric heating
Authors: Akaoui Sami E. 
Published: April 2003

AbstractFirst it is shown how the equations used for the numerical solution of the transient heat transport to a body can be reduced to the simple transport model (of Paper I), which is commonly used in the textile literature for estimating the heat transfer coefficient (h) of the various fabric heating equipment. During the thermal treatment of a fabric that can be approximated by a geometrically stable homogeneous plate, the simple transport model should not be used for calculating h in cases of high heating rate equipment (e.g., direct contact units) instead; the numerical solution should be used. For a fabric that becomes geometrically unstable during a thermal treatment, like polyester knits, the h value obtained by fitting the numerical solution to the fabric heating rate measurement becomes an apparent coefficient that is the function of the fabric thermal history rather than the equipment heating efficiency. However, if the objective of the modelling is to represent the geometrically unstable fabric heating rate, the simple transport expression is a viable alternative to an otherwise intricate model.
Carbon‐fiber‐reinforced phenolics
Authors: Chang E. P. , Kirsten R. O. , Harrington H. J. , Slagowski E. L. 
Published: April 2003

AbstractCarbon‐fiber‐reinforced (CFR) phenolic composites with equivalent mechanical properties and much superior thermal stability to laboratory‐prepared and present commercial epoxy analogs have been achieved by reinforcing 35‐50 wt % of an amine‐catalyzed resole with either the Hercules' Magnamite carbon fabric or the Great Lakes' Varinit carbon fiber/glass cloth hybrid. Improvement of the interlaminar shear strength (ILSS) of the hybrid‐reinforced phenolic laminates was observed with increasing molding pressure and alternate carbon/glass/carbon/glass geometry. Sizings on the carbon fiber do not have any significant effect on the mechanical properties.
Mechanical properties of polypropylene/crosslinked rubber blends
Authors: Dao K. C. 
Published: April 2003

AbstractMechanical properties of rubber‐modified polymers are not single‐valued functions of rubber/matrix type and rubber content, but also vary with processing conditions. The variations in mechanical properties with processing conditions arise mainly from changes in rubber‐phase dispersion. In our past work, by lightly crosslinking the rubbers to increase their melt tenacity and strength, we have succeeded in producing fine and consistent dispersions despite diverse processing conditions. In this study, mechanical properties of polypropylene/lightly crosslinked rubber blends are compared with those of polypropylene/uncrosslinked rubber blends. The results indicate that, like dispersion, mechanical properties of polypropylene/crosslinked rubber blends also appear to be consistent and independent of process variables. The influences on mechanical behavior of degree of crosslinking, rubber content, and rubber/matrix type are also discussed.
High‐temperature coupling of high‐speed GPC with continuous viscometry. I. Long‐chain branching in polyethylene
Authors: Lecacheux D. , Lesec J. , Quivoron C. 
Published: April 2003

AbstractThe coupling of a high‐temperature liquid chromatograph (Waters 150C) with a home‐made continuous capillary viscometer is described. This detector is the only one suitable for high‐speed GPC when the small volume of the mobile phase prohibits the coupling with a classical viscometer. The pressure drop of the GPC effluent through the capillary is continuously measured along with the refractive index change. This dual detection leads to the determination of the intrinsic viscosity as a function of the elution volume, thus allowing a precise use of Benoit's universal calibration. The accuracy of our system is demonstrated in the case of the characterization of linear and branched polyethylene samples. The results concerning the average molecular weights as well as the branching factors (structure parameter g′ and long‐chain branching frequencyλ) are in close agreement with those obtained by the classical way (coupling traditional GPC and discontinuous viscometry). It is well known that an estimate of the λ coefficient is extremely dependent on several hypotheses. However, for a set of commercial low‐density polyethylenes, we obtained λ values about 0.5 × 10−4, with no marked change along the molecular weight range.
Static versus dynamic evaluation of cushioning properties of plastic foams
Authors: Gruenbaum Gad , Miltz Joseph 
Published: April 2003

AbstractThe protective properties of several plastic foams, represented by cushioning curves calculated from static stress–strain curves, were compared to those obtained in shock tests. It was found that the amount of energy absorbed in the two types of tests is almost the same, while the force applied to the product is about 30–50% higher in the dynamic test. Accordingly, the relatively simple static test may be used for choosing the most suitable foam for protection of a fragile product.
Addition polyimides. I
Authors: Varma Indra K. , Gupta Ashok K. , Sangita  , Varma D. S. 
Published: April 2003

AbstractCrosslinking of 4,4′(bismaleimido)diphenyl ether (BM) was investigated in presence of bis(m‐aminophenyl)methylphosphine oxide (BAP), tris(m‐aminophenyl)phosphine oxide (TAP), diaminodiphenyl ether (E) and 3,3‐bis(p‐aminophenyl)phthalide (AP). These crosslinked resins were examined for thermal stability by thermogravimetric analysis. A slight decrease in initial decomposition temperature, the temperature of maximum rate of weight loss, was observed, though the char yield in nitrogen atmosphere at 800°C did not change appreciably. Glass‐cloth‐reinforced laminates were fabricated from BM and amine mixtures. An improvement in mechanical properties was observed in the presence of phosphorus‐containing di‐ and triamines.
Transient sorption of sulfur dioxide in epoxy resin of aliphatic diglycidyl ether
Authors: Ranade G. R. , Nadgir V. M. , Plank C. A. , Laukhuf W. L. S. 
Published: April 2003

AbstractDiffusion of sulfur dioxide in epoxy resin of aliphatic diglycidyl ether was studied performing differential sorption kinetic measurements at temperatures ranging from 1°C to 45°C and activities varying from 0.12 to 0.55. The diffusion of sulfur dioxide appears to be Fickian over the entire temperature range studied. There is a marginal increase in the diffusion coefficient with increase in concentration. The diffusion coefficients evaluated from both “small times” data and “large times” data are in reasonable agreement.
Crosslinking kinetics and network formation in organic coatings containing hexamethoxymethylmelamine
Authors: Bauer D. R. , Budde G. F. 
Published: April 2003

AbstractWe have developed a kinetic model of the crosslinking reaction of hydroxy‐functional acrylic copolymers with fully alkylated melamines. This model accurately describes the extent of the crosslinking reaction as a function of cure time and melamine concentration in coating films. Using this model, we have determined the effects of acid catalyst concentration and strength and the effects of cure temperature on the rate constant of the crosslinking reaction. The rate constant is proportional to the catalyst concentration and to the square root of the acid constant of the catalyst. The temperature dependence of the rate constant follows an Arrhenius rate law with an activation energy of 12.5 kcal/mol independent of catalyst type. Amine salts of p‐toluenesulfonic acid have been compared with p‐toluenesulfonic acid as catalysts in these coatings at different bake temperatures. These kinetic results have been used in a network structure model to calculate the cure response of these coatings as a function of formulation variables.
Effect of metal cyanourates on some properties of PVC
Authors: Gancheva Tamara Stancheva , Kolarova Maria Nikolova , Marinova Atanasia Todorova , Alaminov Christo 
Published: April 2003

AbstractThe effects of barium, lead and calcium cyanourate on the properties of poly(vinyl chloride) and its compositions were investigated. In concentrations up to 2 vol. % they decreased the Tg and Tm of the polymer. Physical and mechanical properties (tensile strength, impact strength, and hardness) are improved. The thermostability (dynamic and static) increases with increasing concentration.
Stabilization of gamma‐irradiated poly(vinyl chloride) by epoxy compounds. III. Conjugated double bonds and degree of unsaturation in gamma‐irradiated PVC–stabilizer mixtures
Authors: Lerke G. , Lerke I. , Szymański W. 
Published: April 2003

AbstractThe concentration of conjugated polyene sequences was studied in γ‐irradiated PVC with 4% admixture of four epoxy stabilizers: diglycidyl ether of 2,2‐bis(4‐hydroxy‐3‐methylphenyl)propane (I), styrene oxide (1,2‐epoxy ethyl benzene) (IV), epoxidized ricinus oil (VI), and epoxidized soybean oil (Drapex 6.8) (VII). As in the former investigations (Papers I and II), the process of the formation of the polyenes occurs in two stages. The concentration of polyene sequences with n double bonds, Hn the total amount of polyene sequences, ∑Hn, the average length of the polyene sequence, n, and the two extents of reaction x and p, were computed. The stabilizing effect of all compounds used agrees with the increasing content of epoxy groups. The addition of stabilizers diminishes the value of n. The decrease of the fraction of long sequences and the increase of short ones occurs. Apart from the binding of evolved HCl, the protective effect towards the macromolecules of PVC consists mainly in the inhibition of growth of chain dehydrochlorination by the epoxy groups.
Differential gel permeation chromatography for quality control
Authors: Runyon J. R. 
Published: April 2003

AbstractFor the direct comparison of similar polymers, as, for example, for quality control, differential gel permeation chromatography provides a simple, sensitive technique that is relatively insensitive to operational variables. One polymer is chosen as a standard and a solution of that polymer is used as the eluent in an otherwise conventional GPC. Differential chromatograms of slightly different polymers are both positive and negative with respect to the baseline. Positive portions represent an excess and negative portions a deficiency as compared to the standard. As in conventional GPC, the elution volumes of the differences indicate the molecular size ranges of the differences. The algebraic sum of the differences is zero. Examination of the raw curves with only general information about calibration and operating conditions tells nearly as much about the differences as carefully executed conventional GPC with complex data reduction.
Rheological properties of mixtures of molten polymer and fluorocarbon blowing agent. I. Mixtures of low‐density polyethylene and fluorocarbon blowing agent
Authors: Han Chang Dae , Ma Chin‐Yuan 
Published: April 2003

AbstractThe viscosities of mixtures of low‐density polyethylene and fluorocarbon blowing agent were determined from the measurement of wall normal stress along the longitudinal axis of a capillary die. For the study, three different grades of commercial high‐pressure low‐density polyethylene were used, together with the following fluorocarbon blowing agents, dichlorodifluoromethane (FC‐12), dichlorotetrafluoroethane (FC‐114), and blends of FC‐12 and FC‐114. In the experiment, blowing agent concentration and melt temperature were varied for each combination of polymer and blowing agent employed. Analysis of the experimental data has led to a correlation between the viscosity reduction factor (VRF) and the blowing agent concentration, in which VRF is defined as the ratio of the viscosity of polymer‐blowing agent mixture to that of the polymer alone. It was found that the correlation obtained is independent of shear rate and temperature and dependent upon only the type of fluorocarbon blowing agent. The practical significance of the correlation is discussed. We have shown that the entrance pressure drop obtained in the absence of phase separation in the entrance region may be used as a measure of the elastic properties of mixtures of fluorocarbon blowing agent and low‐density polyethylene resin.
Morphology of polyurethane modified by plasticizing, blending, or reinforcing
Authors: Blaga A. , Feldman D. 
Published: April 2003

AbstractThe morphology of modified thermoplastic PU has been studied by SEM and DSC. The PU was modified by addition of various amounts of dibutyl phthalate (DBP) plasticizer, vinyl polymers (PVA, PVAc, PVC, VAc–VC copolymer), polysiloxane or fiber reinforcement (glass or cotton) to diolpolyether, followed by mixing and vigorous stirring with dephenylmethane diisocyanate. SEM observations indicated that PU and its modifications have a cellular (foam) structure. A homogeneous matrix was observed in binary blends of PU and DBP in ratios of 20:1 down to 6.6:1; PVA, PVAc, VAc–VC copolymer with a weight ratio of 40:1, PU containing glass fiber (20:1) or cotton fiber (40:1). Blends of PU—with PVA at a weight ratio of 20:1, with PVC in ratios from 20:1 down to 5:1, or with polysiloxane polymer—were heterogeneous and thus not miscible, as evidenced by SEM observations. With the exception of the PU—PSO mixtures, the thermal behavior of the heterogeneous blends did not permit any conclusion regarding miscibility.
Resorbable materials of poly(L‐lactide). II. Fibers spun from solutions of poly(L‐lactide) in good solvents
Authors: Gogolewski S. , Pennings A. J. 
Published: April 2003

AbstractFibers of poly(L‐lactide) (PLLA) with a tensile strength up to 1.2 GPa and Young's modulus in the range of 12–15 GPA were obtained by a hot drawing of fibers spun from solution of PLLA in good solvents such as dichloromethane and trichloromethane. The tensile strength of fibers was strongly dependent on the molecular weight of PLLA and on polymer concentrations in the spinning solution. Changing of the polymer concentration in the spinning solution gives rise to formation of fibers with different shape and porosity. Fibers spun from 10–20% solutions at room temperature exhibit a regular structurization, due to the melt fracture. These fibers had knot strengths up to 0.6 GPa, whereas fibers with a smooth surface spun from more dilute solutions had weaker square knots up to 0.3 GPa.
Electron spin resonance measurements of Cu++ distribution in cation exchange membranes
Authors: Vásquez R. , Ávalos J. , Volino F. , Pineri M. , Galland D. 
Published: April 2003

AbstractElectron spin measurement of the local Cu++ concentrations have been performed in different cation exchange membranes by comparison with reference frozen aqueous solutions of Cu++ salts. Comparison of the obtained values with the average chemical concentrations has therefore permitted direct evidence of microphase separation in these systems. Local concentrations approximately four times larger than average chemical concentrations have been found. Information about composition of this ion‐containing phase has also been obtained from changes in local Cu++ concentrations versus water content.
The time–temperature dependence of the complex modulus of keratin fibers
Authors: Danilatos G. D. , Postle R. 
Published: April 2003

AbstractThe dynamic modulus and loss angle of wet keratin fibers have been measured at frequencies between 6 and 1500 Hz in the temperature range 0.2–45°C. Some further measurements were performed at different relative humidities. These results have been compared with other known results, and the agreement or discrepancies found are discussed. A theoretical curve fit has been introduced for a selected set of experimental results.
A new method of determining the optical properties of cotton fibers using polarizing interference microscopy
Authors: Żurek W. , Zakrzewski S. 
Published: April 2003

AbstractThe refractive indices, birefringence, and cross‐sectional area of cotton fibers was measured using interference polarizing microscope constructed by M. Pluta. A new technique was suggested by realizing the measurements at the perpendicular position of the duplicated image of fiber to the interference fringe. The proposed procedure is a combination of modification of Hamza method and Pluta dual wavelength method, and it was possible to measure at once the three mentioned features of single fiber at one time.
Miscible blends of a vinylidene chloride/vinyl chloride copolymer with aliphatic polyesters
Authors: Woo E. M. , Barlow J. W. , Paul D. R. 
Published: April 2003

AbstractA copolymer of vinylidene chloride and vinyl chloride containing 13.5% by weight of the latter has been solution blended with four aliphatic polyesters: poly(ϵ‐caprolactone), poly(2,2‐dimethyl‐1,3‐propylene adipate), poly(1,4‐cyclohexanedimethylene succinate), and poly(2,2‐dimethyl‐1,3‐propylene succinate). Each blend was examined visually and by differential scanning calorimetry. All blends with the copolymer form a single miscible amorphous phase at all compositions and all temperatures except for the latter mentioned polyester, which exhibits liquid–liquid phase separation at temperatures above a measured cloud point curve. Information about interactions between the components in each blend is estimated from melting point data and discussed.
Compatibility of poly(2,6‐dimethyl‐1,4‐phenylene oxide)/poly(fluorostyrene‐co‐chlorostyrene) blends
Authors: Vuković Radivoje , Kurešević Vjera , Šegudović Nikola , Karasz Frank E. , Macknight W. J. 
Published: April 2003

AbstractThe compatibility of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) with random copolymers of ortho‐ and para‐fluorostyrene as well as with ortho‐ and para‐chlorostyrene of various copolymer compositions was examined. The compatibility was studied by DSC and visual observation of film clarity. It was found that copolymers of ortho‐fluorostyrene with para‐chlorostyrene containing 15–74 mol % p‐CIS are compatible with PPO in all proportions. Compatibility of the PPO/poly‐(ortho‐fluorostyrene‐co‐ortho‐chlorostyrene) system was observed for copolymers containing between 15 and 36 mol % ortho‐chlorostyrene. Copolymers of para‐fluorostyrene with para‐chlorostyrene, as well as copolymers of para‐fluorostyrene with ortho‐chlorostyrene appear to be incompatible with PPO at 210°C.
Reinforcement as a hindrance in the disentanglement of unknotted chains
Authors: Macarthur A. , Stephens H. L. 
Published: April 2003

AbstractObservation of many tangles supports a loop mechanism of entanglement in macroscopic systems. The untangling of an unknotted tangled cord gives curves resembling the behavior under constant stress of an uncrosslinked elastomer. Reinforcement as a function of filler loading has been calculated for a model system consisting of uniform spherical particles in an unknotted tangled matrix. These calculated curves show the maxima found in real systems. Reinforcement also increases with decreasing particle size. The effect on the entanglement of porous particles and particles forming surface attachments with the polymer have been considered. The maximum in the calculated reinforcement curve shifts toward higher filler loading with increasing surface activity. This shift is independent of particle size and suggests a method for assessing the relative effectiveness of different coupling agents.