bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diffusion of dye mixtures in nylon 6. Binary mixtures of disperse dyes
Authors: Kim Jin‐Woo , Iijima Toshiro 
Published: April 2003

AbstractThe diffusion of binary dye mixtures of markedly different chemical constitutions (4‐nitro‐4′‐aminoazobenzene and 1‐amino‐4‐hydroxyanthraquinone) and of similar ones (1‐amino‐4‐hydroxyanthraquinone and 1,4‐dihydroxyanthraquinone) into nylon 6 film was examined. Apparent diffusion coefficients of dyes in the mixture within a single dyeing were determined by the film roll method at 60°, 70°, 80°, and 90°C. Diffusion coefficients of individual dyes used in a mixture of chemically dissimilar dyes are found to change little in comparison with single dyeings, while diffusion coefficients of dyes of similar structures are decreased appreciably. It is suggested that the latter effect is due to the interaction between two dyes in the fiber substrate.
Reactivity of poly(vinyl chloride) containing N‐methyl‐N‐carboxymethyl dithiocarbamate toward metal ions in heterogeneous system and effect of γ‐irradiation on the reactivity
Authors: Nakagawa Tsutomu , Taniguchi Junichi , Fujiwara Yukihiko 
Published: April 2003

AbstractThe reaction of poly(vinyl chloride) containing N‐methyl‐N‐carboxymethyl dithiocarbamate (PSDC) with metal ions in a heterogeneous system and the effects of γ‐irradiation on the reactivity were studied. Slurried PSDC has an affinity for a number of metal ions in aqueous solutions. On the basis of analyses for nitrogen and sulfur and on infrared spectra, a possible chelating structure for PSDC was deduced. The gaseous products evolved during the gamma radiolysis of PSDC under vacuum were measured. Although the dithiocarbamate group bonded to the main chain gave some protection against the dehydrochlorination of poly(vinyl chloride) component, a small amount of the carboxymethyl group was decomposed. It was found that with γ‐irradiation doses up to 30 Mrad, only about 1 mole‐% out of 17.6 mole‐% of N‐methyl‐N‐carboxymethyl dithiocarbamate in the polymer was decomposed. It was shown that the reactivity of the irradiated PSDC in water toward metal ions was almost the same as that before irradiation.
The determination of the addition variation and geometrical isomerism of a polybutadiene as a function of molecular weight by preparative gel permeation chromatography and infrared analysis
Authors: Mirabella Francis M. , Barrall Edward M. , Johnson Julian F. 
Published: April 2003

AbstractThe addition variation, 1,2 and 1,4 units, and the geometrical isomerism, 1,4‐cis and 1,4‐trans units, of a fractionated polybutadiene were determined as a function of molecular weight using preparative gel permeation chromatography followed by infrared analysis of the fractions. Both the addition variation and geometrical isomerism remained essentially constant across the molecular weight distribution.
Ultrahigh molecular weight polyethylene as used in articular prostheses (a molecular weight distribution study)
Authors: Crugnola Aldo M. , Radin Eric L. , Rose Robert M. , Paul Igor L. , Simon Sheldon R. , Berry Mark B. 
Published: April 2003

AbstractCurrently there is widespread use of ultrahigh molecular weight polyethylene (UHMWPE) acetabular components in total joint replacement prostheses. What has been most surprising about the wear of UHMWPE under such circumstances is the occurrence of brittle fracture. Such fracture had not been observed in the usual engineering tests done in the laboratory on UHMWPE. It was only when prosthese which had been removed from patients were examined or run in hip joint simulators with serum or synovial fluid as the lubricant, that brittle fracture was encountered. The problem of environment‐enhanced brittle fracture in plastics dates back to 1946. Interestingly, the phenomenon was first described in polyethylene. The prime variables involved are polymer molecular weight, sensitizing environment, stress filed, and temperature. Other things being equal, brittle behavior in polyethylene is extremely sensitive to the amount of low molecular weight polymer present. In the light of the foregoing we have studied the molecular weight distribution in six commercially available UHMWPE components. These were obtained from six different manufacturers. The specimens were characterized both on their bearing (wear) surfaces and in their interior bulk. The results obtained indicate that:

The UHMWPE components contain substantial amounts of low molecular weight polymer.
The UHMWPE components differ significantly in molecular weight distribution.
The UHMWPE components contain substantial amounts of crosslinked polymer.
Polymer flow through capillaries of variable diameter
Authors: Chee K. K. , Yap Y. H. , Rudin A. 
Published: April 2003

AbstractA polystyrene melt has been extruded through successive capillaries arranged to produce converging and diverging flow patterns through the twin orifices. Applied pressure at fixed mass flow rate through the combined dies is equal to the sum of the pressure drops in the single capillaries in both flow modes. The Bagley end correction was found to apply to each die in the sequence. Bagley plots were linear with a particular upper capillary at given apparent shear rate in the lower die. No effect of shear history could be detected on the viscous behavior of the polymer, but preshearing in converging flow produced a slight reduction in die swell.
Stress growth and relaxation of a molten polyethylene in a modified weissenberg rheogoniometer
Authors: Nazem F. , Hansen M. G. 
Published: April 2003

AbstractA Weissenberg rheogoniometer was modified1‐3 to improve sample temperature uniformity and constancy (to within ±0.5°C) and to give a quicker response to normal thrust changes (estimated gap change ≤0.1 μm/kg thrust; gap angle = 8.046°; gap radius = 1.2 cm; servomechanism replaced by an open‐loop cantilever spring of 10 kg/μm stiffness). Low‐density polyethylenes (IUPAC samples A and C, melt index at 190°C = 1.6) at 150°C were used in step‐function shear rate experiments. Inspection of marked sectors in the samples showed substantial uniformity of shear at values of Ṡ = 0.1, 2, and 5 sec−1; for Ṡ = 10 sec−1 and S ≤ 2 shear units (S = Ṡt), the shear was highly nonuniform at and near the free boundary. Using selected premolded samples A, scatter in seven replicate tests at Ṡ = 1.0 sec−1 did not exceed ±6% for N1(t) and ±5% for σ(t) (N1 = primary normal stress difference; σ = shear stress; t = time of deformation from the initiation of experiment at zero time). N1(t) and σ(t) data agreed with Meissner's1; for Ṡ = 0.1, 2.0, 5.0, and 10.0 sec−1, torque maxima occurred at S = 6 shear units, and thrust maxima occurred in the range of 10 to 20 shear units. σ(t) and N1(t) data do not satisfy the van Es and Christensen4 test for rubber‐like liquids with strain rate invariants included in the memory function. On cessation of shear (after a shear strain S at constant shear rate Ṡ), initial values of −dσ(t)/dt and −dN1(t)/dt were found to depend strongly on S, in some cases passing through maxima as S was increased. After shearing at Ṡ = 0.1 sec−1 for 500 sec, such that stresses became constant, stress relaxation data satisfied Yamamoto's5 equation of dN1(t)/dt = −2Ṡσ(t).
Development of an autographic falling‐weight impact system
Authors: Gonzalez Henry , Stowell W. J. 
Published: April 2003

AbstractThe objective of this project was to develop a system that would allow the determination of the energy absorbed during fracture in a falling‐weight impact test. Equipment was developed which would allow the force exerted by the impact tup on the specimen to be determined during the test. Using this information and the equations developed, it was possible to convert force‐versus‐time traces on an oscilloscope to energy absorbed. Tests were conducted to compare the autographic method with the normal falling‐weight method. The system was shown to give results which are similar to results from normal falling‐weight impact tests, but requires much fewer specimens. Tests can be made and results can be obtained on small sample sizes, since results are obtained for each specimen tested. Also, a more representative value of falling‐weight impact strength can be determined in cases where there are mixed failure modes. The autographic system may be used in those instances where there are limitations of material, and with further use it may eventually replace the normal falling‐weight impact determination.
Behavior of cellulose grafted with poly(methyl methacrylate) and polyacrylonitrile toward some direct and reactive dyes
Authors: Kamel M. M. , Hebeish A. 
Published: April 2003

AbstractViscose rayon fibers modified with polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA) were dyed with some direct and reactive dyes. Exhaustion rate of the dye onto fibers was governed by the amount and nature of the polymer grafted. In general, the dye affinity for cellulose and dye exhaustion onto fibers decreased as the graft yield increased. Dye affinity for the PAN–cellulose graft copolymers was greater than that found with PMMA–cellulose graft copolymers. Except in a few cases, the tendency of cellulose graft copolymers of ca. 13% graft to accept direct dyes was more than that of the untreated cellulose, whereas the affinity of reactive dyes for cellulose graft copolymers of up to ca. 43% polymer was more than that of untreated cellulose. The dye fixation, based on the weight of cellulose component, increased as the graft yield increased. The dyeability of cellulose oxidized with ceric ammonium nitrate was also examined. Oxidation of cellulose prior to dyeing reduced the affinity of the dye for cellulose.
Investigation of high‐density polyethylene film surface treated with chromic acid mixture by use of 2,4‐dinitrophenylhydrazine
Authors: Kato Koichiro 
Published: April 2003

AbstractHigh‐density polyethylene films were treated with chromic acid mixture. 2,4‐Dinitrophenylhydrazine was reacted on the treated films. The changes in amounts of 2,4‐dinitrophenylhydrazones formed in the films were inferred by comparing the absorptions in the ultraviolet spectra. The changes in the film surfaces by chromic acid mixture treatment were investigated by comparing the changes in the amount of the hydrazones with changes in water wettability of the treated films. Scanning electron micrographs of the treated film surfaces were taken. Oxidation of the film surface zone, partial breakdown of polymer in the film surface zone, and oxidation of surface zone bared from the film inner zone seem to have occurred with increase in treatment time. When the treatment temperature was raised, the increase in carbonyl groups in the surface of the high‐density polyethylene film with rise in treatment temperature seems to have been prevented by an increase in partial breakdown of polymer in the film surface.
Polyblends. I. Mechanical properties of polyblends of butadiene–acrylonitrile elastomers and copolymers of vinyl stearate and vinyl chloride
Authors: Jordan Edmund F. , Artymyshyn Bohdan , Riser George R. , Wrigley A. N. 
Published: April 2003

AbstractSeveral nitrile rubber elastomers were polyblended, across the composition range, with selected polymeric compositions containing vinyl chloride. The compositions incorporated were (a) bulk poly(vinyl chloride) (PVC); (b) copolymers of vinyl stearate and vinyl chloride containing, respectively, 0.21, 0.36, and 0.47 weight fraction of the vinyl ester; and (c) mixtures containing the same weight fractions of di‐2‐ethylhexyl phthalate (DOP) with PVC. Mechanical, viscoelastic, optical, and volatility properties were studied on all blends in this first paper. To accurately compare the mechanical properties of polyblends of different systems, a criterion of mechanical equivalence was taken as the observance of similar stresses at break for compositions selected to have identical 100% moduli. Optimum mechanical equivalence, therefore, occurred at the largest ratios of 100% modulus to break stress for all systems compared. Optimum mechanical property equivalence was observed for NBR blends with PVC and for similar blends of both internally and externally plasticized systems containing 0.21 weight fraction of plasticizer. However, considerably more nitrile rubber was needed for PVC blends to acquire the properties of the plasticized systems. Mechanical equivalence was observed, but was not optimum for systems having more plasticizer because tensile strengths were lower. Polyblending with NBR improved the toughness and low‐temperature properties of starting vinyl stearate copolymers. Improved toughness was indicated by the expansion of areas under stress–strain curves. Refractive index matching appeared to explain the transparency of the best films and their relative freedom from haze. On heating at 85°C, poly(vinyl chloride) and the copolymer polyblends suffered no volatility loss. Volatility of DOP from the blends was 1.5 times greater than for PVC–DOP mixtures. Because modulus–temperature curves and mechanical Tg values of the filler component shifted with composition, the mechanical behavior of these blends was in harmony with an accepted standard of interdomain compatibility.
Polyblends. II. Isochronal viscoelastic parameters for polyblends of butadiene–acrylonitrile elastomers and copolymers of vinyl stearate and vinyl chloride
Authors: Jordan Edmund F. , Artymyshyn Bohdan , Riser George R. , Wrigley A. N. 
Published: April 2003

AbstractIsochronal viscoelastic parameters were obtained for the polyblends of nitrile rubbers with internally and externally plasticized poly(vinyl chloride) (PVC) whose mechanical properties were studied in the previous paper. Thus, the room‐temperature mechanical properties of the previous paper were extended to included a wide temperature range in this work. Phase immiscibility, indicated by the observance of two glass transition temperatures, using differential scanning calorimetry, was observed for most of the polyblends. In contrast, blend compatibility was indicated by mechanical measurements, because the inflection temperatures of the isochronal curves (Ti) shifted with blend composition. It was concluded that mechanical spectroscopy‐monitored volume elements large enough to include contributions to viscoelastic response from both phases; this caused the curves to shift with composition. On the other hand, the much shorter‐range segmental responses characteristic of Tg produced transitions at the discrete temperature intervals representative of each phase. Using a relation between torsional stiffness at room temperature and tensile strength, failure strengths with respect to temperature were estimated and compared at varied free‐volume increments (T − Tg) up to 50°C. Approximate equivalence was found by this procedure for fillers of bulk PVC and those containing 21 wt‐% of both internal and external plasticizer, in analogy with findings for mechanical property optimization of the previous paper. Low‐temperature properties and viscoelastic response of the polyblends containing vinyl stearate copolymers were greatly improved over their neat state. In addition, data from isochronal temperature–composition diagrams suggested viscoelastic equivalence, but greater ease of processability for the blends containing vinyl ester, compared to the others.
Oxidation behavior of isoprene/styrene copolymer and butadiene/styrene copolymer
Authors: Sakota Kazuyuki , Okuno Kenji , Okaya Takuji , Tsuchiya Shizuo 
Published: April 2003

AbstractThe oxidation behavior of emulsion isoprene/styrene copolymer (SIR) and emulsion butadiene/styrene copolymer (SBR) by heat aging of ultraviolet irradiation in air has been investigated from the change of gel fraction, intrinsic viscosity, molecular weight distribution, and mechanical properties. Upon oxidation by heat aging, SIR predominantly undergoes chain scission and shows only a slight change of mechanical properties, whereas SBR predominantly undergoes crosslinking and sharply becomes brittle. Upon oxidation by ultraviolet irradiation, SIR undergoes both chain scission and crosslinking and shows almost no substantial change in mechanical properties, whereas SBR predominantly undergoes crosslinking and sharply becomes brittle. The probability ratio of chain scission to crosslinking with oxidation by heat aging or ultraviolet irradiation was determined by the method of Charlesby et al. The results can reasonably explain the oxidation behavior of the copolymers described above.
Effects of cyclic loading on the dynamic viscoelastic properties of crosslinked polymers reinforced with randomly distributed short glass fiber
Authors: Kodama Minekazu 
Published: April 2003

AbstractThis study describes the effects of the application of cyclic uniaxial loading on the viscoelastic response properties of two crosslinked copolymers which contain short, randomly distributed glass fibers as reinforcing agents. The additional viscoelastic dispersion, observed with unstressed glass‐filled polymers and which occurs somewhat above the primary glass transition temperature of the matrix resin, disappeared as a result of the applied cyclic loading. A concurrent lowering of the rubbery modulus of the composite was observed.
Oxidative degradation of poly(vinyl chloride)
Authors: Decker Christian 
Published: April 2003

AbstractRates of oxygen consumption and formation of oxidation products were determined in γ‐initiated oxidation of poly(vinyl chloride) (PVC) at 25°C. Data are given for five dose rates and correlated on the basis that the overall oxidation is the sum of two reactions that are first order and half order in rate of initiation. The principle oxidation product is hydroperoxide, formed by the half‐order reaction, whereas alcohol and carbonyl compounds result mostly from first‐order reactions. These products account for 77–80% of the total oxygen absorption. The presence of oxygen was found to increase twofold the rate of dehydrochlorination of irradiated PVC. A reaction scheme is developed which assumes that a significant fraction of the interactions of tertiary peroxy radicals is nonterminating and yields alkoxy radicals which propagate or decompose by β‐scission. This decomposition occurs mostly by splitting off a chlorine atom with formation of a ketone and, to a lesser extent, by CC cleavage which accounts for the observed decrease in molecular weight of the oxidized PVC. Polystyrene was found to be much more resistant to oxidation than PVC. A classification of some commercial polymers in function of their susceptibility to oxidation is proposed.
Theoretical predictions of the elastic moduli of polymer‐impregnated hardened cement paste and mortars
Authors: Whiting D. , Kline D. E. 
Published: April 2003

AbstractHardened coment pastes with water‐to‐cement (w/c) ratios of 0.4 and 0.6 and hydration times of one, three, seven, and 28 days were oven dried and subsequently impregnated with an epoxy resin formulation which was then polymerized in situ at 75°C. Portland cement mortars containing Ottawa sand and asbestos fibers as filler were also subjected to this impregnation process. Dynamic elastic moduli (E′) were measured at audio frequencies over a range of temperatures (100–400°K). Experimental values were compared with moduli calculated using various theoretical approaches based on two‐phase composite materials theory. Best agreement between experimental and calculated results occurs when Wu's theory for spherical polymer inclusions was applied to a cement‐based matrix. In the case of polymer‐impregnated mortars, experimental and theoretical results are in closest agreement at low temperatures and at low volume fraction of filler.
Slow release of water‐soluble salts from polymers
Authors: Narkis Nava , Narkis Moshe 
Published: April 2003

AbstractRelease rates of NaCl and NaF from mixtures with polystyrene, polyethylene, thermosetting polyester, and crosslinked polyethylene have been studied. Salt/polymer granules were prepared by melt mixing under different conditions. The release process was studied in batch as well as continuous systems. The salt release from polymer into water depends on such parameters as salt content, temperature, water flow rate, and salt particle size.
Water‐soluble polymers as retention aids in a model papermaking system. II. Poly(vinylpyridines)
Authors: Howard G. J. , Hudson F. Lyth , West Jeremy 
Published: April 2003

AbstractThree poly(4‐vinylpyridines) and a poly(2‐vinylpyridine) were studied for their effectiveness at increasing the retention of titanium dioxide a model papermaking system at pH 3.8. All the polymers are very efficient retention aids and do not greatly increase the time for the paper sheet to be formed. They are well adsorbed by both cellulose fibers and titanium dioxide. Although fiber suspensions are weakly flocculated by the poly(vinylpyridines), pigment suspensions are stabilized. Flocculation studies on mixed suspensions show that the poly(vinylpyridines) have a powerful heterocoagulation effect which mirrors the retention results. Some results are also reported in which the pH is brought to 6.5; under these conditions, polymer adsorption and its consequent effects compete with polymer precipitation.
Calibration of gel permeation chromatography columns using polydisperse polymer standards
Authors: McCrackin Frank L. 
Published: April 2003

AbstractTwo methods of calibrating gel permeation chromatography columns are given. The first method uses polymer standards that may have broad molecular weight distributions. Either the weight‐, number‐, or viscosity‐average molecular weight of each standard must be known. This method neglects column peak spreading. The second method requires polymer standards of moderately narrow molecular weight distributions for which both the weight‐ and number‐average molecular weights are known. However, the second method determines both the column peak spreading and calibration of the column. The second method is applied to calibration of a column using polystyrene standards. The column peak spreading is found to be small and independent of molecular weight for this column.
Bimodal character of polyester–solvent interactions. III. The effects of morphology on the nature of the interaction of nonaqueous solvents with the aromatic and the aliphatic ester residues of poly(ethylene terephthalate)
Authors: Knox B. H. 
Published: April 2003

AbstractThe extent of solvent‐induced shrinkage, swelling, and crystallization of polyester is found to be dependent on the initial morphology of the material. However, the nature of the interaction of the nonaqueous solvents with the aromatic and the aliphatic ester residues of poly(ethylene terephthalate) is found to be independent of morphology and only dependent on the differences in the stereochemical nature of the given solvent and polyester residue.
The absorption of direct dyes by crosslinked cellulose. I. The equilibrium of dyeing
Authors: Ibe E. Chianakwalam , Valko Emery I. 
Published: April 2003

AbstractThe effect of the degree of chemical crosslinking of cellulose with two bifunctional crosslinking agents dimethylol ethylene are (DMEU) and bis (hydroxyethyl) sulfur (BHES), on the equilibrium absorption of the direct dyes Chlorazol Sky Blue FF (C.I. Direct Blue 1) and Chrysophenine G (C.I. Direct Yellow 12) has been reported. The results show the increasing reduction of equilibrium dye absorption with increasing crosslink density. However, the maximum loss of absorption is about less than half of the amount absorbed by uncrosslinked cellulose. The results have been interpreted by reference to the parameters affecting the free energy of dyeing and the relevant models (pore model and gel model) available for explaining the fine structure of swollen cellulose.