bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on polymer blend of nylon 6 and polypropylene or nylon 6 and polystyrene using the reaction of polymer
Authors: Ide Fumio , Hasegawa Akira 
Published: April 2003

AbstractIn the presence of maleic anhydride‐grafted polypropylene, marked dispersibility of the polymer blend of isotactic polypropylene and nylon 6 was obtained. This appeared to be caused by the formation of a certain graft polymer between maleic anhydride in polypropylene and terminal amino groups of nylon 6. The same phenomenon was observed when polystyrene and nylon 6 were blended with styrene–methacrylic acid copolymer as the interpolymer. The existence of such a graft polymer was confirmed by solvent extraction, estimation of the amino group of nylon 6, and identification by differential scanning calorimetry. The physical properties, especially mechanical properties of nylon 6–polypropylene polymer blends, were remarkably improved with increase of maleic anhydride added to the polymer blend. On the other hand, the physical properties those of nylon 6–polystyrene polymer blends were very little improved even in the presence of good dispersibility.
Reaktionsverlauf während der Härtung eines Epoxidharzes mit Dimethylaminopropylamin
Authors: Eyerer Peter 
Published: April 2003

AbstractDer Vernetzungsverlauf eines Epoxidharz–DMAPA‐Systems wird mittels UR‐Spektroskopie, Kalorimetrie, Zugfestigkeits‐, Mikro‐ und Makrohärte‐, Gleichstromwiderstands‐ und Schubmodulmessungen untersucht. Die Bestimmung des zeitlichen Verlaufes der Glastemperatur während der Vernetzung führte zur physikalischen Aufklärung von Eigenschaftsanomalien bei höheren Vernetzungstemperaturen. Eine Erklärung für den eigenartigen Verlauf der Glastemperatur konnte dagegen nicht gegeben werden.
Préparation, structure et propriétés des membranes obtenues par greffage radiochimique d'acide acrylique sur des films minces de terphane en présence d'agents gonflants
Authors: Marchand J. , Puig J. R. 
Published: April 2003

AbstractLe greffage de films de 6 microns d'épaisseur en poly(téréphtalate d'éthylène glycol) (PTEG), de marque Terphane, avec l'acide acrylique, conduit à des membranes exploitables en électrodialyse mais inutilisables en osmose inverse. La technique radiochimique permet de réaliser le greffage dans des conditions très satisfaisantes. Les observations portant sur la cinétique du greffage, sur le gonflement des films greffés, sur leur resistance électrique, sur leur cristallinité et enfin sur leur structure révélée par microscopie électronique permettent de mieux comprendre le mécanisme du greffage et mettent en évidence des corrélations étroites entre la structure des films greffés, les conditions du greffage et les propriétés des membranes résultantes. Le rǒle joué par les zones amorphes dans le système considéré revět une importance primordiale: les zones amorphes sont seules susceptibles de recevoir l'acide acrylique et de permettre la formation en leur sein de poly(acide acrylique). Ce dernier s'accumule dans les zones amorphes où sa concentration tend vers une limite déterminée concurremment par deux facteurs. D'une part la barrière physique des zones cristallines s'oppose à l'extension du greffage. D'autre part les conditions měmes de la réaction, dans la mesure où l'état d'enchevětrement ou de réticulation qui peut s'établir entre les chaǐnes de poly(acide acrylique) finit par s'opposer à l'arrivée du monomère, peuvent créer éventuellement une seconde limite au développement de la réaction. Le diphényle utilisé comme agent gonflant paraǐt favoriser l'extension des zones amorphes par l'attaque des zones cristallines. Il est possible que sa présence conduise en outre à un poly(acide acrylique) de poids moléculaire plus faible donc de structure moins enchevětrée et plus ouverte à la diffusion de l'eau, ce qui expliquerait qu'une perméabilité à l'eau ait seulement pu ětre obtenue par greffage en présence de diphényle. L'acide formique utilisé également comme agent gonflant semble avoir eu un résultat opposé en donnant lieu à des taux de gonflement plus faibles. Il est possible que ce composé favorise la formation de poly(acide acrylique) de haut poids moléculaire aboutissant à un pseudo‐gel par enchevětrement moins facilement gonflable. En conclusion, ce travail montre que dans les conditions utilisées, le greffage du PTEG par l'acide acrylique tend vers un taux limite déterminé principalement par le degré de cristallinité. L'armature cristalline du PTEG n'est pratiquement pas altérée. Les propriétés du PTEG sont très diversement affectées par le traitement. La perméabilité à l'eau et la résistance mécanique sont peu modifiées plors que par contre la conductivité électrique est considérablement augmentée.
Effect of stoichiometric concentration of hardener and percentage styrene oxide diluent on the crosslinking and mechanical properties of an epoxy resin cured with DEAPA
Authors: Whiting D. A. , Kline D. E. 
Published: April 2003

AbstractEpoxy resin was cured with diethylaminopropylamine (DEAPA) in amounts ranging from 10% to 50% of stoichiometric amount. The yield strength of resulting thermosets formed by heat curing at 75°C is found to increase with decreasing amount of hardener. This is attributed to a more densely crosslinked structure resulting from increased tertiary amine‐initiated epoxide–epoxide chain reaction and decreased primary and secondary amine–epoxide reaction. Infrared analysis and swelling data are also presented. Styrene oxide diluent is found to have a moderate effect on mechanical properties in the range from 10 to 25 parts per hundred (phr).
Structure development during melt spinning of linear polyethylene fibers
Authors: Dees J. R. , Spruiell J. E. 
Published: April 2003

AbstractApparatus has been developed for studying the development of crystallinity and orientation during the melt spinning of synthetic fibers. Tension in the fiber and temperature, diameter, and x‐ray diffraction patterns are measured as a function of distance from the spinneret for a running monofilament. Measurements are presented for linear polyethylene over a range of spinning variables together with other investigations carried out on the final as‐spun fibers. These data indicate that the development of crystallinity in polyethylene is controlled by a balance between increased crystallization kinetics caused by the stress in the fiber and a tendency for increased supercooling with change in any spinning variable that increases cooling rates in the fiber. The type of crystalline orientation observed, its development during the spinning process, and the changes observed with changes in spinning conditions suggest a model for the as‐spun fiber structure in which varying amounts of row nucleation and twisting of lamellar, folded‐chain crystal overgrowths occur depending on the spinning conditions. As‐spun fiber birefringence was shown to depend primarily on the crystalline orientation. Mechanical properties correlated well with c‐axis crystalline orientation function and spinline stress.
Crosslink density of elastomers. A new gas‐chromatographic method
Authors: Parks C. R. , Brown R. J. 
Published: April 2003

AbstractThe crosslink density of small microtomed samples of rubber vulcanizates has been determined using a gas‐chromatographic method for estimating the amount of solvent in the swollen rubber. The method may be used for determining the variation in crosslink density through thick rubber articles, for determining the change in crosslink density after aging service, or, for the investigation of rubber bonds and interfaces.
Studies of some peculiar effects of temperature on molten high‐density polyethylene properties
Authors: Tanaka Koichi , Takakura Makoto , Koshino Yuji 
Published: April 2003

AbstractMany HDPE samples show peculiar behavior of melt viscosity at low shear rate and melt strength at constant extrusion rate in a temperature region of about 200° to 250°C. It was found that the degree of the peculiarity of the behavior was affected by temperature, residence time at a temperature, the temperature rise rate, and the kind and quantities of additives. It was concluded that the peculiar effects were due to the crosslinking that a chemical reaction produced. An attempt was made to express the different behaviors of temperature dependence of melt viscosity among many HDPE samples by some simplified equations. It is suggested that both the peculiar changes with temperature of the melt viscosity and those of the melt strength may be produced by the same mechanism. The similarity of the phenomena between HDPE samples exposed to high temperatures and those crosslinked by γ‐rays was found. Finally, a possibility is discussed of predicting the processability of the resin and properties of final products before the processing operation.
Rapid assessment of weathering stability from exposure of polymer films. I. Real and simulated weathering of commercial ABS terpolymers
Authors: Davis A. , Gordon D. 
Published: April 2003

AbstractChanges in the infared transmission spectra of thin films were used to follow the natural and artificial weathering of ABS terpolymers. Photo‐oxidation of the polybutadiene moiety, which is the major process involved, occurs only after a well‐defined amount of ultraviolet energy has been absorbed. Therafter, unsaturation decreases in a first‐order manner with respect to UV energy absorbed. Under artificial conditions with constant UV intensity, energy absorbed is synonymous with time, but this is not so in natural exposure because of the variability of solar energy and its UV content. The method permits rapid comparison of commercial grades of ABS with the advantage of using natural conditions. It has been shown that pigmentation (3.6 phr brown and 1.25 phr carbon black) increases weathering stability two‐ and fourfold respectively, as assessed by induction energy and rate of disappearance of unsaturation.
Rapid assessment of weathering stability from exposure of polymer films. III. Relative weathering stability of ABS and arylon, a related polymer blend
Authors: Davis A. , Gordon D. 
Published: April 2003

AbstractArylon, a blend of an aromatic polysulfone and a terpolymer of acrylonitrile–butadiene and α‐methylstyrene, weathers similarly to ABS. However its first‐order rate constant for the loss of unsaturation is only 0.39 cm2(Wh)−1 as against 0.80cm 2(Wh)−1 for ABS. This slower weathering is probably caused by the decrease in light intensity penetrating Arylon compared with ABS as a result of the high degree of light scattering observed in the former.
Spectroscopic investigation of hydrocellulose phenylosazones in cadoxen solution
Authors: Blair H. S. , Cromie R. 
Published: April 2003

AbstractSolutions of hydrocellulose phenylosazone in cadoxen are stable when oxygen is excluded. In the presence of oxygen, the absorption spectrum changes, but the change is partially reversible when nitrogen is bubbled through the oxidized solution. It is probable that a hydroperoxide of the hydrocellulose phenylosazone is formed initially and is then decomposed by the basic solvent. The work indicates the importance of using deoxygenated solvents and working in an oxygen‐free atmosphere when preparing cadoxen solutions of hydrocellulose phenylosazone.
Photochemical reactions of high polymers. XIII. Photografting of methyl methacrylate onto the polymers bearing thiosulfate groups
Authors: Tsunooka Masahiro , Ando Nobuya , Tanaka Makoto 
Published: April 2003

AbstractPolymers bearing pendent thiosulfate groups, that is, sodium poly(vinyl benzyl thiosulfate) (PVBB) and the sodium salt of poly(vinyl hydrothiosulfatoacetate)(PV AcB), were prepared. The photograft polymerization of methyl methacrylate onto these polymers was carried out. The relationships between irradiation time and conversion, degree of grafting, and grafting efficiency were investigated in the photograft polymerization. It was ascertained that the pendent thiosulfate groups acted as effective initiators for the graft polymerization. From the number of endgroups in the homopolymer formed along with the graft polymer, the mechanism of the graft polymerization was discussed and it was verified that the graft polymerization was initiated by the thiyl radical formed by scission of the sulfur–sulfur bond of the pendent thiosulfate group. An unusually high degree of grafting and extremely rapid polymerization rate observed in the graft polymerization suggested the dual functions of thiosulfate‐bearing polymer as initiator and emulsifier. It was found that addition of FeCl2 to this polymerization system increased the rate of polymerization and the degree of grafting but decreased the grafting efficiency. The effect of FeCl2 was interpreted by assumption of a photo‐redox reaction between thiosulfate group and Fe2+.
Photostabilizing effect of Ni(II) chelates in polymers. I. Polystyrene
Authors: Harper D. J. , McKellar J. F. 
Published: April 2003

AbstractThe photostabilizing effect of six Ni(II) chelates in films of polystyrene is compared with their efficiency in quenching triplet benzophenone and a correlation between the two established. In both polymer stabilizing and triplet quenching experiments, the diamagnetic chelates are more effective than the paramagnetic chelates, indicating that the structural arrangement of the ligand around the Ni atom is an important factor in both cases.
Interaction of melt spinning and drawing variables on the crystalline morphology and mechanical properties of high‐density and low‐density polyethylene fiber
Authors: White James L. , Dharod Khushal C. , Clark Edward S. 
Published: April 2003

AbstractAn experimental study of the spinnability and the variation in crystallinity and orientation in high‐density and low‐density polyethylene fibers with melt spinning and drawing conditions has been carried out. Three polymers (two high‐density and one low‐density) and eicosane (C20H42) were studied. The maximum spinnability was in the lower molecular weight high‐density polyethylene. Hermans‐Stein a, b, and c crystallographic axis orientation factors were computed from wide‐angle x‐ray scattering patterns. In the spun fiber, small take‐up velocities cause the b axis to become perpendicular to the fiber axis in each fiber. The c axis increasingly orients itself parallel to the fiber axis as take‐up velocity increases. The a axis orientation is different for each polymer. The results are interpreted in terms of modern theories of crystalline morphology, specifically the development of row structures. In the drawing experiments, the two high‐density polyethylenes necked. A phenomenological theory of necking is discussed. The a, b, and c axis orientation factors were determined for different stages of drawing. In the necked regions and in completely drawn fibers, the c axis was parallel to the fiber axis and the a and b axes are perpendicular to the fiber axis. The tangent Young's modulus and tensile strength of the spun fibers increased with take‐up velocity and in the drawn fibers were an order of magnitude higher than in the spun fiber. The mechanical properties of spun fiber may be correlated with the c axis (Hermans) orientation factor. The drawn fiber shows significant variations in Young's modulus and tensile strength at constant unit cell orientation.
Studies on melt spinning. V. Elongational viscosity and spinnability of two‐phase systems
Authors: Han Chang Dae , Kim Young Woo 
Published: April 2003

AbstractIsothermal melt spinning experiments were carried out to investigate the elongational flow behavior and spinnability of polymer blends and a calcium carbonate‐filled polypropylene. Blends chosen for study were mixtures of polystyrene (Dow Chemical, Styron 678) with high‐density polyethylene (Union Carbide, DMDJ 4309), and mixtures of polystyrene (Dow Chemical, Styron 686) with high‐density polyethylene (Union Carbide, DMDJ 4309). For the study, measurements were taken of the thread diameter by photographic techniques and of the thread tension by means of a Saxl tensiometer. These measurements were later used to determine the elongational viscosity of the material investigated. It was found that, in all the blends and filled systems investigated, the elongational viscosity decreases with elongation rate and that the relationship between the elongational viscosity and blending ratio is very complex. An attempt is made to offer explanations of the observed complicated relationship with the aid of microphotographs of fiber samples, which display the complexity of fiber morphology in two‐phase systems. It was also found that there exists some correlation between the elongational viscosity and the maximum stretch ratio which may be considered as representing fiber spinnability.
Water permeability of poly(diallyl isophthalate) films
Authors: Rybicky J. , Marton J. P. 
Published: April 2003

AbstractThe prepolymer of diallyl isophthalate is employed as a material for a moistureprotective coating which is applied in the solution form, free of radical initiator. The effect of the absence of radical initiator, temperature and time of cure, and thickness of coat is evaluated in terms of the permeability of water through the protective films of the polyphthalate. Temperature of the noncatalytic cure can be as low as 170°C, and the presence of an initiator in the coating formulation does not bring about any improvement in the moisture resistance of the films.
Effect of resin chemisorption and crosslinking on various fiber properties of cotton
Authors: Patel S. B. , Kulshreshtha A. K. , Mehta P. C. 
Published: April 2003

AbstractChemisorption and crosslinking of cotton cellulose has been carried out with DMEU, DMPU, DHEU, and DMDHEU. Various physicochemical properties of resin‐treated samples have been studied and the data subjected to a linear regression analysis. Using the techniques of liquid retention and optical microscopy it has been found that the chemisorbed cotton is characterized by a lower level of bound resin, greater amount of methylol HCHO, and higher swellability of structure in comparison to the crosslinked cotton. This difference of behavior between the two cottons is attributed to greater rigidification and a collapse of porous structure in crosslinked cotton as a result of catalytic activity at the curing temperature. For various resin‐treated samples there exists a linear relationship between the strength and recovery characteristics of single fibers and those of fiber bundles. The losses in fiber strength and extensibility are found to be proportional to the level of bound resin in various samples. Crosslinked fibers show appreciably higher magnitudes of elastic recovery and bundle crease recovery than chemisorbed fibers. The significance of these results is discussed.
Electric field‐assisted grafting of 4‐vinylpyridine on an activated cation exchange membrane
Authors: Belliveau John F. , Bobalek Edward G. , Simard Gerald L. 
Published: April 2003

AbstractThe influence of forced diffusion by a d. c. electric field on the graft polymerization of ionic 4‐vinylpyridine onto a host membrane was determined. The host was a commercial cation exchange membrane. Initiation was by a redox couple of titanious ions at the exchange sites of the membrane and t‐butylhydroperoxide in the bulk solution along with the monomer. Undesirable effects of electrode reactions were avoided by isolation of the electrode compartments with permselective membranes. Measurements were at monomer concentrations of 0.05, 0.1, and 0.2M and d.c. current densities of 0.08 and 0.16 mA/cm2. Applying the field accelerated the graft rate and provided greater control of the amount and distribution of the polymer than when free diffusion alone directed the reaction. This suggests possible value of forced diffusion by an electric field to tailormake membranes to special properties such as in the case of ampholytic mosaic membranes.
Compressive behavior of worked plastics
Authors: Shayota Mofak , Babcock Stephen G. 
Published: April 2003

AbstractThe effect of temperature and loading history on the compressive stress–strain properties of two plastics is described. Polypropylene and nylon cylindrical specimens were reduced in height by 20%, 40%, 60%, and 80%, at room temperature and 25°F below the melt point and at two different deformation rates. Test specimens were cut from these worked billets along two directions, axially and radially. Subsequent compressive stress–strain tests were run using an Instron tester. Results of these tests are presented and compared with the stress–strain curve of the virgin material.
Thermodynamic properties of liquid polyethylene
Authors: Maloney D. P. , Prausnitz J. M. 
Published: April 2003

AbstractThermodynamic properties of molten polyethylene are calculated for the temperature range 100° to 300°C and for pressures up to 3000 atmospheres. The calculations are based on limited experimental data augmented by a corresponding‐states correlation and an empirical equation of state. Specific volume, internal energy, enthalpy, entropy, and solubility parameter are presented as functions of temperature and pressure. The results of this study may be useful for engineering design in the high‐pressure polyethylene process.
Dispersions or solutions? A mechanism for certain thickening agents
Authors: Taylor N. W. , Bagley E. B. 
Published: April 2003

AbstractHydrolyzed starch–polyacrylonitrile (H‐SPAN) graft copolymers form highly viscoelastic mixtures with water, even at concentrations less than 1% by weight. In many ways these mixtures behave like ordinary polyelectrolyte solutions, but dilution experiments revealed that linear reduced viscosity–concentration plots could not be obtained even under ostensibly isoionic dilution conditions. This result, combined with a determination of gel content from centrifugation studies, led to the conclusion that high viscosity H‐SPAN water mixtures consist of swollen, deformable gel particles closely packed in intimate contact. Under high dilution or at high ionic strength conditions, the gel particles no longer are tightly packed, solvent is present in excess, the viscosity drops precipitously, and the thickening action effectively disappears. For comparative purposes, a commercial thickening agent (Carbopol 941) was examined and found to act in the same way. All reduced viscosity‐concentration curves obtained by dilution, either with salt solutions or water, can be shifted to a single normalized reduced viscosity plot. This shift is done by using as the concentration variable the quantity cQ, where c is the polyelectrolyte concentration and Q is the swelling which the gel particles undergo in an excess of solvent at the corresponding total ionic strength of the solution of concentration c.
Mechanism of low profile behavior in unsaturated polyester systems
Authors: Pattison Victor A. , Hindersinn Raymond R. , Schwartz Willis T. 
Published: April 2003

AbstractThe mechanism by which low profile character is achieved in unsaturated polyester systems has been investigated. Using techniques of microscopy, data are developed that support a model in which micro stress cracking is induced to relieve stress promoted by polymerization shrinkage. Thus the strain is accommodated internally in a molded part, rather than through macroscopic shrinkage of the article.