bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fundamental studies on solvent dyeing with tetrachloroethylene. III. Effect of water added to the solvent dyebath on the diffusion of disperse dyes in poly(ethylene terephthalate)
Authors: Morita Zenzo , Kuchiki Kanesada , Kobayashi Ritsuko , Motomura Hiromi 
Published: April 2003

AbstractThe diffusion and adsorption of disperse dyes on poly(ethylene terephthalate) (PET) from the tetrachloroethylene (TCE) dyebath were investigated by the method of cylindrical film roll when water was added to the TCE dyebath. The diffusion coefficients of three disperse dyes were increased with an increase in the addition of water to the TCE dyebath, and that of C.I. Disperse Violet 8 showed a peak. The solubilities of water in TCE in the absence and presence of disperse dye were measured at 90°C by Karl Fischer titration. The solubilities in TCE were 0.040 in the absence of dye and 0.041–0.045 g H2O/100 g TCE in the presence of disperse dye. In the presence of Violet 8, the solubilities showed a peak with increasing addition of water. The effect of water addition on the diffusion coefficients was attributed to the dissolution of water in the TCE dyebath. The water dissolved in TCE brought about an additional swelling of PET swollen previously by TCE. No marked influence on the surface concentration of dye was observed by the water addition to TCE.
Prediction of dynamic and transient rheological properties of polystyrene and high‐density polyethylene melts from the molecular weight distribution
Authors: Bersted B. H. 
Published: April 2003

AbstractA model relating the steady‐shear melt viscosity and elasticity to the molecular weight distribution in HDPE and polystyrene melts has been extended to predict the dynamic viscosity, modulus, and loss modulus. Limitations in the model as applied to the dynamic properties are discussed. The model is also applied to the transient response of stress growth during steady shearing. This application is considered useful because it may help describe nonsteady‐state flow of polymer melts in short dies and cyclic operations as employed in commercial molding equipment.
Purification of polymeric dyes by ultrafiltration
Authors: Cooper Anthony R. , Booth Robin G. 
Published: April 2003

AbstractUltrafiltration has been evaluated as a method for the purification of of polymeric dyes. Transport data for solvent and solutes were obtained for several polymer‐impurity mixtures and different membrane types. Relatively low molecular weight impurities were found to be significantly rejected by these membranes. A critical concentration of sodium chloride or sodium hydroxide was found to be necessary to effect efficient transport of these species. Gel permeation chromatography was used to monitor these separations and characterize the purity of the polymeric dyes produced. Impurity concentrations in the final product were typically less than 500 ppm.
Bulk polymerization of acrylonitrile. II. Model development
Authors: Garcia‐Rubio L. H. , Hamielec A. E. , MacGregor J. F. 
Published: April 2003

AbstractA model for bulk polymerization of AN is developed. It adequately predicts conversion‐time histories and molecular weight development in the temperature range of 40°–80°C with AIBN as initiator. It is shown that this model has predictive powers by simulating nonisothermal conversion–time histories.
Acrylonitrile copolymer films: Influence of modification by reaction with ethylene oxide on biological degradation
Authors: Courtney J. M. , Hood R. G. , Ewart J. M. 
Published: April 2003

AbstractThe biological degradation of acrylonitrile–dimethylaminoethyl methacrylate and acrylonitrile–acrylic acid copolymers has been studied by evaluating copolymer films in a continuous in vitro rumen system. The copolymer films were examined before and after modification by reaction with ethylene oxide gas. The degradation of the acrylonitrile–dimethylaminoethyl methacrylate copolymer followed a pattern similar to that occurring on thermal degradation. Modification by reaction with ethylene oxide gas, which induces CN conjugation, did not improve the resistance to degradation. The acrylonitrile–acrylic acid copolymer films disintegrated, but on prior modification by reaction with ethylene oxide they remained virtually unaltered. Modification of the acrylonitrile–acrylic acid copolymer results in crosslinking with an absence of CN conjugation, leading to improved resistance to biological degradation.
Formation and behavior of mechanoradicals in pulp cellulose
Authors: Hon David N.‐S. 
Published: April 2003

AbstractThe mechanical degradation of pulp cellulose fiber was studied at ambient temperature and at 77°K. ESR findings reveal that mechanical degradation occurs via free‐radical routes. Three types of mechanoradicals contributing singlet, doublet, and triplet ESR signals are identified. The singlet signals are derived from the alkoxy radicals at C4positions as a consequence of the cleavage of glucosidic bonds, the radical pairs generated at C1positions contributing the doublet signals. Triplet signals are derived from the C2and C3positions due to the cleavage of C2and C3bonds. Of these radicals, alkoxy radicals are the most stable at ambient temperature. Carbon radicals are capable of interacting rapidly with oxygen molecules to produce peroxy radical intermediates, where alkoxy radicals are inert toward oxygen molecules. ESR study also reveals that cellulose mechanoradicals are capable of initiating vinyl polymerization. MMA propagating radicals are identified when the monomers are in contact with cellulose mechanoradicals. The ability of mechanoradicals to initiate graft copolymerization from cellulose fiber is discussed.
Temperature dependence of reinforcement in the composites polyurethane rubber–crosslinked polymeric filler
Authors: Kolařík J. , Hudeček S. , Lednický F. , Nicolais L. 
Published: April 2003

AbstractThe temperature dependence of the components of the complex tensile and shear modulus of composites thermoplastic polyurethane rubber (Estan 5707)–crosslinked polymeric filler has been determined using torsional pendulum and Rheovibron viscoelastometer techniques. For comparison, dynamic mechanical properties of the system Estan 5707–glass beads were determined. The temperature dependence of the relative modulus (modulus of composite/modulus of matrix) of the former composites exhibited a pronounced maximum at about 50°C above the glass transition temperature of the matrix. This maximum of reinforcement was discussed in terms of (a) immobilized interfacial layer, (b) broadening of the spectrum of relaxation times, and (c) increase in the glass transition temperature of the matrix. From the excess reinforcement, i.e., the discrepancy between experimental data and theoretical prediction, an apparent thickness of the immobilized layer was calculated.
Elucidation of the fine structure of poly(vinyl chloride) by hydrogenation and 13C‐NMR analysis of low molecular weight fractions
Authors: Schwenk Ulrich , Cavagna Friedrich , Lömker Franz , König Inge , Streitberger Horst 
Published: April 2003

AbstractThe following experiment was performed based on the assumption that the characteristic structural features of high molecular weight poly(vinyl chloride) (PVC) should be present to the same extent in its low molecular weight fractions. Two PVC fractions of molecular weight, 1500 and 800, respectively, (0.14% of total polymer) were isolated from bulk PVC (Mn 32,000) by extraction with methanol. This extract was transformed into paraffins by a new hydrogenation method using an excess of Raney nickel in order to facilitate identification. 13C‐NMR spectral data of the paraffins showed that almost 2 out of 1000 carbon atoms were linked to a side chain with more than five carbon atoms, and 5 out of 1000 carbon atoms were methyl branched. Gas chromatography‐mass spectrometry (GC–MS) analyses confirmed that the low molecular weight paraffins consisted of a sequence of even‐numbered homologs. These findings suggest indirectly that the surprisingly low degradation temperature of PVC is due to the arrangement of the chlorine atoms rather than to the branching of the alkyl chain.
Copolymers of 3,3′,4,4′‐tetraaminobiphenyl and 1,2,4,5‐tetraaminobenzene with 1,1′‐bis(glyoxalyl)‐ferrocene and 1,1′‐bis(phenylglyoxalyl)ferrocene
Authors: Vernois Michel , Williams H. Leverne 
Published: April 2003

AbstractFour monomers were synthesized and four copolymers prepared. The polymers were dark‐colored, poorly soluble, crystalline products. The x‐ray photographs were typical of triclinic crystals. The polymers degraded at temperatures lower than those characteristic of the analogous homopolymers. The recovered polymers were ferromagnetic.
The measurement of dynamic flexile properties of fibers with a rheovibron viscoelastometer
Authors: Murayama Takayuki 
Published: April 2003

AbstractA new method for measurement of dynamic flexile mechanical properties was developed by a modification of the Rheovibron viscoelastometer. The Rheovibron instrument is useful for obtaining dynamic tensile mechanical properties of films and fibers over a wide temperature range. A new flexile grip and procedure were used for measuring dynamic mechanical properties of material in the flexile mode using the Rheovibron instrument. The dynamic flexile properties on polyester, nylon 66, and acrylic fiber are presented.
PVC powder extrusion. Melting properties and particle morphology
Authors: Kulås Finn Ragnar , Thorshaug Niels Peter 
Published: April 2003

AbstractThe extrusion of unplasticized PVC powder has been studied. Powder blends with low amounts of lubricants have been used in order to observe differences between structurally different PVC powders. Experiments with varying screw speeds indicate that resins consisting of agglomerated, small, globular primary particles are more sensitive to shear and deformation in the extruder channel than more compact particles. Frictional heat seems to be dissipated inside loosely agglomerated resin particles, possibly because of a larger internal surface. This additional heat, which depends on the shear rate, influences the melting behavior considerably. Scanning electron microscopy shows that PVC particles seem to melt without first breaking into smaller particles. A comparison between bulk‐polymerized and suspension‐polymerized PVC with nearly the same particle structure reveals a close similrity in melting properties. The results obtained in this work indicate that structural differences may explain the differences in melting behavior often observed when rigid PVC blends are extruded.
Diffusivity and solubility of organic vapors in modified polyethylene films. III. Solubility studies
Authors: Aboul‐Nasr Osman T. , Huang Robert Y. M. 
Published: April 2003

AbstractA dynamic absorption technique was employed to determine the solubility of benzene, hexane, and heptane in modified polyethylene films. Films were modified by solvent annealing, crosslinking, and combinations thereof. Solvent annealing was found to increase the solubility while crosslinking led to its diminution. The effect of combined treatment on the solubility was found to be dependent on the sequence of treatment, the swelling power of the conditioning agent, and the irradiation dose. A slight effect of the solvent‐diffusant pair was also observed. The solubility of the various vapors in crosslinked films was found to vary linearly with temperature. Solubility of some vapors in some of the conditioned films showed maxima with respect to temperature. The changes in solubility were explained in terms of the relative changes in the molecular volume of the diffusant and of the segmental mobility of the network chains with the various experimental conditions.
Solvent barrier property for fluorinated polyethylene
Authors: Hayes L. J. , Dixon D. D. 
Published: April 2003

AbstractSolvent barrier studies for fluorinated polyethylene have shown that the fluorinated surfaces reduce the rate of permeation for many solvents. The barrier property has been related to physical and chemical properties of the solvent. For instance, solvents having a dielectric constant between 7 and 10 were not retained as well as solvents with a dielectric constant less than 7.
Partially dehydrochlorinated PVC. II. Reactions with dienophiles and hydroxylating agents
Authors: Wirsén Anders , Flodin Per 
Published: April 2003

AbstractSamples of poly(vinylchloride) containing polyene sequences were made by partial dehydrochlorination by alkali in tetrahydrofuran solution, by alkali in dioxane, and thermally in dimethyl‐formamide. The reactions of polyene PVC were followed by UV spectrophotometry. Dienophiles were found to have relative reactivities similar to those found in reactions with low molecular‐weight dienes. The reaction with maleic anhydride yielded polymers which after hydrolysis contained carboxyl groups. Hydroxylation was made with osmium tetraoxide and performic acid. With the latter reagent the reaction proceeded to complete disappearance of the UV‐absorption peaks from trienes and higher polyenes: Gel permeation chromatography analysis showed that hydroxylation could be made with only minor changes in molecular‐weight distribution. The formation of gel upon thermal dehydrochlorination in DMF was shown to be due to physical cross linking probably arising by crystallization of polyene segments. The adhesion of the hydroxylated and carboxylated polymers to glass and stainless‐steel surfaces was investigated. Films adhered stronger as the degree of dehydrochlorination of the polyene PVC used to make the derivative increased. Samples with long sequences adhered much stronger than those containing short sequences of corresponding degrees of total substitution.
The manganic hydroxide–hydrazine system as an initiator of vinyl polymerization. III. The emulsion polymerization of methyl methacrylate
Authors: Rahman A. , Brown C. W. 
Published: April 2003

AbstractEmulsion polymerization of methyl methacrylate with the manganic hydroxide–hydrazine system has been studied. An attempt was made to corroborate earlier evidence that the initiation may involve a surface reaction on an insoluble manganese compound. The surface area of the manganic hydroxide was varied, and the effect of this variation on the rate of decomposition of hydrazine was examined. A correlation was found between the polymerization rate and the surface area of the precipitate.
Flame‐retardant effect of tris(2,3‐dibromopropyl) phosphate on polystyrene
Authors: Inagaki Norihiro , Sakurai Shiro , Katsuura Kakuji 
Published: April 2003

AbstractThe flame‐retardant effect of tris(2,3‐dibromopropyl) phosphate (TBPP) on polystyrene was investigated using thermogravimetry, infrared spectroscopy, gel permeation chromatography, and electron spectroscopy for chemical analysis (ESCA). The following results and conclusions were obtained: (1) The addition of TBPP (about 3 wt%) to polystyrene had flame‐retardant properties. (2) The addition of TBPP resulted in lowering the temperature of the burning surface and the amount of volatile products. TBPP increased the thermal stability of polystyrene. (3) TBPP inhibited oxidative attack on polystyrene. In the presence of TBPP the formation of peroxide groups at the burning surface was inhibited. It is inferred that this inhibition decreases the evolution of flammable fuels from the burning surface and contributes flame‐retardant properties. There is a lesser possibility that TBPP acts as a physical barrier that limits oxygen access. At present there is no idea of why TBPP inhibits thermoxidative reactions of polystyrene.
Complexes of tetramethylthiuram disulfide with zinc dialkyldithiocarbamates and their role in the sulfur vulcanization of natural rubber
Authors: Ducháček V. , Frenkel R. 
Published: April 2003

AbstractTetramethyl thiuram disulfide, which functions as an inhibitor of the zinc dialkyldithiocarbamate‐accelerated sulfur vulcanization, has been investigated by Mooney scorch measurements at 120°C and continuous measurements in a Vuremo curometer at temperatures from 100 to 140°C. The inhibition effect is due to the formation of a complex with zinc dialkyldithiocarbamate. The stability of the complex was calculated using the Hückel method which includes charge self‐consistency on the central atom. The calculations are in a good agreement with the experimental results which illustrate that tetramethylthiuram disulfide, unlike an actual prevulcanization inhibitor, plays a significant role in all the stages of vulcanization. It decreases the crosslinking rate and increases the ultimate extent of vulcanization and its activation energy.
Deformational, swelling, and potentiometric behavior of ionized gels of 2‐hydroxyethyl methacrylate–methacrylic acid copolymers
Authors: Ilavský M. , Dušek K. , Vacík J. , Kopěek J. 
Published: April 2003

AbstractThe deformational, swelling, and potentiometric behavior of ionized water‐swollen gels of 2‐hydroxyethyl methacrylate (HEMA)–methacrylic acid (MA) copolymers used in biomedical and separation applications was investigated. With increasing degrees of neutralization α, the swelling degree strongly increases and the modulus Gs decreases. For the copolymers with MA content ⩾ 30 mole‐%, the dependence of Gs on α passes through a minimum. Comparison of the results with the modified theory of rubber elasticity shows that the decrease in Gs at low concentrations of charges on the chain is controlled mainly by the degree of swelling. At higher α, both the finite extensibility of network chains, caused by a high degree of swelling, and electrostatic interactions contribute to Gs. The dependence of the interaction parameter χ on the volume fraction of polymer in the gel, v2, is independent of α and closely resembles the dependence obtained for other hydrophilic polymers.
Polymerization of acrylamide compounds onto Fe plates: An alternative route for applying polymer coatings
Authors: Mengoli Giuliano , Daolio Sergio , Giulio Ugo , Folonari Carlo 
Published: April 2003

AbstractAcrylamide and some of its derivatives were polymerized onto the surface of Fe plates by causing a slight corrosion of Fe to Fe2+ in the presence of perdioxy compounds. In water within a suitable pH range, the acrylamide monomers are likely to store at the metal–solution interface and to absorb on the iron surface. Thus, the polymerization takes place in situ, leading to the formation of uniform film coatings; the presence in the solution of a radical inhibitor imparts considerable stability to the bulk of the system. The dependence of the polymerization kinetics on several variables such as pH, monomer concentration, and peroxide concentration has been determined, and some characteristics of the resulting coatings were investigated.
High‐strength/high‐modulus fibers of p‐phenylene oxadiazole/n‐methyl hydrazide copolymers—a new class of high‐performance organic materials
Authors: Bach Hartwig C. , Dobinson Frank , Lea K. R. , Saunders J. H. 
Published: April 2003

Abstractp‐Phenylene oxadiazole/N‐methyl hydrazide copolymers were prepared by polymerization of terephthalic acid, dimethyl terephthalate, and hydrazine sulfate in fuming sulfuric acid, and coagulation of the polymer was obtained in aqueous sulfuric acid. Fibers spun from these copolymers have unusually high strength and modulus, making these materials attractive for the reinforcement of articles such as tires. Yarn tenacities of 16–21 gpd and moduli of 350–450 gpd were obtained. Yarn of these copolymers showed no significant degradation under conditions to which a tire cord material is subjected in tire building and end use. In their performance in vehicle tires, tire cords were found to be competitive with other reinforcing agents such as fiber glass, steel, and commercial poly(p‐phenyleneterephthalamide).
Grafting onto polyester fibers. III. Electrokinetic properties of acrylic acid and acrylonitrile‐grafted polyester fibers in the presence of cationic dyes
Authors: Lokhande H. T. , Mody N. R. , Rao K. N. , Rao M. H. 
Published: April 2003

AbstractThe electrokinetic properties such as zeta potential, surface charge density, and surface conductivity of polyester fibers grafted with acrylic acid and acrylonitrile were measured when cationic dye solutions were streamed through. The presence of the cationic dyes on the surface of the fibers and their specific adsorption at the carboxylic groups in the acrylic acid graft copolymer produce lowering of zeta potential. The decrease in surface charge density as the percent graft increases is due to the decrease in surface area of the fibers due to the adsorption of the cationic dyes. The same trend is observed with acrylonitrile‐grafted fibers. The surface conductivity of the acrylonitrile‐grafted polyester fibers increases with increase in dye concentration of the streaming solution. The results for the 27.4% grafted sample differed from those of the 7.32% and 12.1% grafts, which is indicative of the formation of a three‐dimensional network causing change in both the physical structure as well as the chemical nature of the surface of the substrate.
Application of the fung equation to the constant strain rate behavior of plasticized polyvinyl chloride
Authors: Dehoff Paul H. 
Published: April 2003

AbstractA quasilinear viscoelastic equation originally proposed by Fung to characterize the uniaxial viscoelastic behavior of rabbit mesentary is used in this study to characterize the viscoelastic behavior of plasticized polyvinyl chloride for strains up to 24%. An experimentally determined relaxation function is used to predict the constant strain rate behavior of plasticized polyvinyl chloride. The predictive ability of the Fung equation is also compared with the well‐known BKZ and Lianis theories. It was found that the Fung equation agrees quite closely with the BKZ and Lianis theories but that all three theories showed only moderate agreement with experiment.
Hydrophilic interpolymer membranes from crosslinked blends of poly(vinylalcohol), poly(styrene sodium sulfonate) and poly(vinyl methyl ether–alt–maleic anhydride)
Authors: Gryte Carl C. , Chen J. , Kevorkian V. , Gregor Harry P. 
Published: April 2003

AbstractInterpolymer ion exchange membranes were prepared from a compatible casting solution that contained poly(styrene sodium sulfonate), poly(vinyl methyl ether–alt–maleic anhydride), and poly(vinyl alcohol). Crosslinking of the films was accomplished through the formation of ester linkages that were stable in aqueous environments. Membrane properties (water content, capacity, concentration potential, equivalent conductivity) were measured over a wide range of membrane compositions. Ultrafiltration was carried out with a feed solution that was 0.01N in KCI and 15 ppm in erythrosin. Rejection and hydraulic permeability data were reported as a function of membrane composition.
Plasma polymerization of tetrafluoroethylene
Authors: Nakajima K. , Bell A. T. , Shen M. , Millard M. M. 
Published: April 2003

AbstractThe plasma polymerization of C2F4 was carried out in both continuous wave and pulsed rf discharges to establish the effects of reaction conditions on the kinetics of polymer deposition and the polymer structure. ESCA spectra of the polymer show evidence for CF3, CF2, and CH2 groups. Under conditions favoring low deposition rates, the dominant functional group is CF2. At higher deposition rates the concentration of CF2 groups is reduced and a more crosslinked polymer is produced. Both polymer deposition rates and polymer structures were essentially identical when using continuous wave and pulsed rf discharges.