bluuebunny/crossref_metadata_2025_split huggingface dataset:
A theory of inclusions in viscoelastic materials
Authors: Radok J. R. M. , Tai Clement L. 
Published: April 2003

AbstractTwo important groups of viscoelastic materials may, in practical applications, be characterized by the presence of inclusions. In high polymers, the control of the production of homogeneous batches presents often unsurmountable difficulties and hence unintended regions of nonhomogeneity will result. In concrete structures, reinforcements are often introduced to ensure strength in tension, and these inclusions, while intentional, are bound to change the behavior of the bulk material. This investigation of the effects of circular cylindrical and spherical inclusions in infinite two‐ and three‐dimensional bodies, subject to uniaxial loading at infinity, has been based on linear viscoelastic theory. It has been assumed that the inclusions are either rigid, perfectly elastic or viscoelastic and that their boundaries are free or welded to the surrounding material. In all these cases, the behavior of the viscoelastic material surrounding the inclusions will differ essentially from that of the material without inclusions. For example, it may be shown that a single parameter material will exhibit several retardation or relaxation times. In view of this situation, the interpretation of experimental test results on viscoelastic materials as well as the practical usefulness of linear viscoelastic theory appear in a new light which is discussed on the basis of the available information.
Adhesion between viscoelastic and hard materials
Authors: Brunt N. A. 
Published: April 2003

AbstractThe steady of peeling off process of a resin layer from a hard substrate can be considered as a rate process, being greatly dependent on temperature. Formulae relating the rate of release, the temperature, and the load with the energy of adhesion and the number of contact points between resin layer and substrate are derived. In the experimental part the energy of adhesion is measured according to these formulae for a number of different combinations of the same resin with glass, glass after removal of the water layers ordinarily adsorbed on a glass surface, and stainless steel. In all these cases there is but very little difference between the real energies of adhesion. Of more importance are time and temperature of the curing of the resin.
Electrochemistry of poly(methyl vinyl ether‐maleic anhydride)‐polyvinyl alcohol membranes
Authors: Spencer H. G. , Hunt O. L. 
Published: April 2003

AbstractThe electrochemical properties of a series of baked poly(methyl vinyl ether‐maleic anhydride)‐polyvinyl alcohol membranes were investigated. Increased baking time and carboxylic acjd content reduced swelling and osmotic flow, and increased the concentration potentials. Near‐maximum concentration potentials were obtained for some membranes in a limited concentration range.
Non‐Newtonian flow of concentrated solutions of high polymers
Authors: Onogi Shigeharu , Kobayashi Tadashi , Kojima Yasuhiro , Taniguchi Yoshishige 
Published: April 2003

AbstractNon‐Newtonian flow of moderately concentrated solutions of polyvinyl alcohol (PVA) in water and polystyrene (PS) in toluene were measured with a Maron‐Krieger‐Sisko viscometer at various temperatures and concentrations. The usual dependences of the apparent and zero shear viscosities for two polymers on rate of shear, temperature, and molecular weight have been found. The log‐log plot of zero‐shear viscosity versus concentration can be represented by two straight lines intersecting at one point (critical concentration cc). The critical concentration in volume fraction of polymer, v2c, multiplied by the chain length Z is not constant but decreases with decreasing Z, although it has the same order of magnitude as the value of Zcv2 obtained from the log‐log plots of viscosity versus Z for many systems of polar and nonpolar polymers. The product ccρZ1/2 (ρ = density of the solution) is constant and independent of Z. To explain the constancy of this product, an equivalent sphere model is presented. When the volume fraction of spheres is assumed to be unity, the extension of molecules agrees very well with the unperturbed extension evaluated from intrinsic viscosity data in ⊖ solvent.
Adhesiveness of polyethylene mixtures
Authors: Bikerman J. J. , Marshall David W. 
Published: April 2003

AbstractThe effect of additions to polyethylene wax on the breaking stress f of butt joints between two steel cylinders depended on the nature of the addition. Oleic acid lowered f in concentrations as small as 0.2%, and in presence of 1% oleic acid f was immeasurably small. Ethyl palmitate slightly diminished f (to about 1/5th of the initial value when the amounts of polyethylene and palmitate were equal), but this decrease was wholly due to the weakening of the polymer itself, and the ratio of f to the tensile strength of polyethylene‐palmitate mixtures was >1 at all compositions. Thus, with oleic acid above 0.2% improper, and with ethyl palmitate at all percentages, proper adhints were obtained. Stearone apparently formed a weak boundary layer and 4‐methyl‐2,6‐di‐tert‐butylphenol gave erratic results as it decomposed on heating and apparently reacted with steel. Addition of ethyl palmitate to polyethylene contaminated with oleic acid made the mixture adhesionable. The solubility of the contaminant in solid polyethylene was more important than polarity. The relation between the composition of an adhesive and the breaking stress of its adhints can be understood if the distinction between proper and improper joints is kept in mind.
Siloxy methylene oxide compounds
Authors: Ender H. H. 
Published: April 2003

AbstractSilicon containing chain and ring formals of the structures
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were synthesized from the reaction of a chlorosilane with formaldehyde or a formaldehyde donor in acid solution or in the presence of an HCl acceptor. Mono‐, di‐, tri‐, and tetrafunctional “silyl formals” were obtained; they are oily products of various degrees of polymerization and of relatively high refractive index and specific gravity. Silyl formals are stable at room temperature. They are useful intermediates in cases in which a siloxy group should be introduced into an organic molecule by reaction with an organic OH group or active hydrogen. Tri‐ and tetrafunctional silyl formals are effective crosslinkers in various systems.
Crosslink formation during aging of natural rubber vulcanizates
Authors: Maisey L. J. , Scanlan J. 
Published: April 2003

AbstractThe effect of antioxidant on the crosslinking reaction occurring during the oxidation of sulphur vulcanizates of natural rubber was investigated by using both continuous and intermittent stress relaxation measurements. Similarly, by means of continuous stress relaxation and equilibrium swelling measurements the crosslinking reaction in vacuum was followed. The presence of antioxidant or removal of air reduced considerably both continuous and intermittent relaxation and also the difference between them, which measures the crosslinking. The crosslink formation must therefore form part of the sequence of oxidative reactions.
The capillary flow of silicones
Authors: Johnson Donald L. , Baer Eric 
Published: April 2003

AbstractThe non‐Newtonian flow of silicone fluids in capillaries was investigated with special emphasis on the viscoelastic nature of entrance and exit effects. At low pressures the power law was obeyed, while at high pressures considerable deviations were observed, particularly with short capillaries. For capillaries with large length‐to‐radius ratios, the flow index and consistency approached the Newtonian values. Entrance effects were successfully analyzed by the method proposed by Bagley. At low shear stresses the end correction was dependent only on the geometry of the apparatus. An elastic contribution to the end correction was observed only at high shear stress, indicating a relatively mild viscoelastic behavior. Additional evidence indicating small elastic effects was obtained from swelling measurements of capillary jets.
Crosslinked polyesters from allyl glycidyl ether and maleic anhydride
Authors: Fischer R. F. 
Published: April 2003

AbstractAllyl glycidyl ether and maleic anhydride, mixed in equimolar quantities, cure together readily in the presence of air, peroxide, and/or Lewis acids. Outstanding properties of the castings formed are hardness (Barcol 50–60 at 25°C., 30 at 150°C.), clarity and heat distortion temperature (165–168°C.). Color is yellow to amber, and strength properties are adequate. Water resistance is fair. The mixture is too thin for convenient use in laminating, but it can be bodied by heating (1 hr., 110°C.), giving a syrup of 50 cpoise. In glass cloth laminates, through‐cure appears to be inhibited by the glass. The addition of styrene overcomes this effect. Small amounts are best (5–20%), since large quantities impair elevated temperature strength. Unusually good strength is attained even at 500°F., but resistance to aging at 500°F. is poor.
Polymeric ligands. V. Derivatives of dimethylglyoxime
Authors: Degeiso R. C. , Donaruma L. G. , Tomic E. A. 
Published: April 2003

AbstractMonomethacrylyldimethylglyoxime and dimethacrylyldimethylglyoxime were prepared by acylation of dimethylglyoxime with methacrylyl chloride. Monoallyldimethylglyoxime and diglycidyldimethylglyoxime were prepared by alkylation of dimethylglyoxime sodium salt with allyl bromide and epichlorohydrin, respectively. The monomethacrylyl derivative formed a copolymer with methyl methacrylate and the dimethacrylyl derivative yielded a homopolymer. Nickel chelates could be formed from both polymers. Diglycidyldimethylglyoxime was easily copolymerized with a number of diamines. A polymer formed as a by‐product from the preparation of the diglycidyldioxime was easily cured with m‐phenylenediamine.
The effect of extraction and rubber purity on the stress relaxation of dicumyl peroxide vulcanizates
Authors: Dunn J. R. 
Published: April 2003

AbstractThe oxidative stress relaxation of peroxide vulcanizates of various grades of natural rubber has been investigated at 100°C. The rubbers were examined both with and without hot acetone extraction before or after cure. Highly purified rubber vulcanizates exhibited autocatalytic relaxation, but those based on crêpe or smoked sheet did not, because they retained natural antioxidant even after extraction. Autocatalysis was no longer found in extracted purified rubber vulcanizates if these were prepared from a mix containing phenyl‐β‐naphthylamine. The presence of such an antioxidant reduced network scission but had less effect upon the amount of crosslinking taking place during aging.
Permeation rate constants for water and salt flux through synthetic membranes
Authors: Skiens W. E. , Mahon H. I. 
Published: April 2003

AbstractWater and salt fluxes through synthetic membranes were measured as functions of pressure. In the pressure range 0–60 atm. both the water permeation rate constant and the salt permeation rate constant were independent of pressure. The water flux increased linearly with pressure driving force (hydraulic‐osmotic). The changes in salt flux were small. These changes were proportional to changes in the activity of the salt solutions due to concentration and pressure effects. Good agreement was obtained between the experimental flux data and the kinetic equations describing the process.
A contribution to the theory of periodate oxidation of starch
Authors: Mejzler D. , Schmorak J. , Lewin M. 
Published: April 2003

AbstractThe mathematical theory of periodate oxidation of unfractionated starches was studied. The degrees of polymerization (DP) of the amylose and amylopectin components of the starch were considered to be unknown, whereas the proportion of amylose in the starch, the repeating chain length of the amylopectin component, and the amount of formic acid evolved on quantitative oxidation were considered to be experimentally ascertainable and thus known. The treatment thus reduces to an approximate solution of one equation with two unknowns. It is shown that certain inequalities are then valid, when the following information can be obtained: (1) the upper and lower DP limits of each component, (2) the extent of degradation of a randomly degraded starch, and (3) the maximum relative errors involved in the determination of the DPs of the components by the periodate method. A numerical example is given to show the application of the method in laboratory practice.
Effect of addition of cations on the simultaneous grafting of styrene to rayon by gamma–irradiation
Authors: Suzuki Ikuo , Ogawa Seiji 
Published: April 2003

AbstractSimultaneous radiation grafting of styrene to rayon in the presence of atmospheric oxygen was accelerated when the rayon was immersed in an aqueous solution of some reducing cation. The irradiation time required for the same amount of grafting as in the case of no addition of salt is reduced by 40 min. or more on the addition of TiCl3, SnCl2, SnCl4, NiCl2, CrCl3, or CoCl2, while FeCl2 has little effect on acceleration. This acceleration is chiefly due to the decrease in the induction period caused by the oxygen in polymer phase. The mechanism of acceleration of grafting is discussed in relation to radiolysis of aqueous solution involving cation.
Polyhydroxyethers. III. Ester derivatives
Authors: Reinking N. H. , Barnabeo A. E. , Hale W. F. , Mason J. H. 
Published: April 2003

AbstractThe esterification of high molecular weight hydroxyether polymers, derived from dihydric phenols and epichlorohydrin, has been studied. The esters of an assortment of monobasic acids, both organic and inorganic, were prepared by reaction of acid halides, anhydrides, esters or free acids with the secondary hydroxyl group in the polymer repeating unit. The effects of the structure of the acid radical and the degree of esterification on polymer properties were determined. In general, esterification resulted in a lowering of the major glass transition temperature of the polymer. This was true at all levels of esterification. Decreased chain symmetry and decreased hydrogen bonding appeared to be the major causes of the observed effect. Permeability of the polymers to oxygen and water vapor was increased by esterification. The increases was found to correlate well with the size and polarity of the acid radical. Some additional properties of the ester derivatives were examined in less detail.
Colorimetric method for measuring polyester degradation due to weathering
Authors: Gray V. E. , Wright J. R. 
Published: April 2003

AbstractChemical changes occurring in thermoset polyesters during exposure to solar and carbon‐arc radiant energy were determined quantitatively by a color reaction with a diamine, N,N‐dimethyl‐p‐phenylenediamine, in a methanol–benzene solution. The amount of diamine reacting with a specimen and the color change of the treated specimen, as measured by differential reflectance, varied directly with exposure time. Three commercial polyesters (glass fiber‐reinforced) exposed under identical conditions showed widely different degradation rates as measured by the amount of N,N‐dimethyl‐p‐phenylenediamine used per specimen. The relative stability of the three materials was independent of irradiation source. The color of the treated specimen was dependent on exposure time.
Polymer structure and gas permeation. I. Thermodynamic interpretation of permeation
Authors: Roberts R. W. , Kammermeyer Karl 
Published: April 2003

AbstractA thermodynamic interpretation of the permeation process of gas transport through polymeric membranes is proposed. The mechanism used does not require the usual P = DS relationship. The dependence of gas permeability upon the crystallinity, strain, etc. is presented, and a method for obtaining values for the entropy of crystallization is suggested. Literature data have been correlated by this approach and values for the entropy of crystallization of polyethylene, polyethylene terephthalate, and nylon 610 were derived.
Tensile strength of gum and reinforced EPR and SBR vulcanizates
Authors: Dudek T. J. , Bueche F. 
Published: April 2003

AbstractThe tensile strength and elongation at break of EPR and SBR gum vulcanizates were determined as a function of network chain density. A large viscous contribution to the tensile force was found at low crosslink density, and the maximum in the tensile strength versus chain density curve decreased as more nearly equilibrium conditions were approached. The rate dependence of tensile strength of black‐filled EPR was studied by creep rupture experiments. The temperature dependence of the tensile strength of filled EPR and SBR was studied and compared. The same limiting degree of cure was obtained for both filled and gum vulcanizates of EPR.
Effect of homogeneity on viscosity in capillary extrusion of polyethylene
Authors: Heitmiller R. F. , Naar R. Z. , Zabusky H. H. 
Published: April 2003

AbstractThe change in melt flow properties, as determined by melt index measurement, as a function of shear history, has been measured for linear polyethylene. It is shown that a drop in melt index occurs when a polymer sample which has had no previous shear history is melted and subjected to shear mixing. This fact is attributed to a molecular homogenization of a previously unmixed blend. An analytical model of the laminar flow in a pipe of concentric adjacent fluids with different viscosities is presented. The model indicates that the effective viscosity of this non‐homogeneous system is much lower than the viscosity of fan intimate blend of the same viscosity of an intimate blend of the same viscosity fluids.
Oxyluminescence of polymers. I. General behavior of polymers
Authors: Schard M. P. , Russell C. A. 
Published: April 2003

AbstractThe faint emission of light by various classes and types of polymers when heated in the presence of oxygen, oxyluminescence, was studied by means of a photomultiplier tube and sensitive microammeter. Among the polymers with a carbon‐carbon backbone, the polymers having the greater number of tertiary carbon atoms generally showed greater intensities of luminosity. Polystyrene was a notable exception to this generalization. The shape of the luminosity versus time curves varied with the type of polymer. It was also found that the emission of light did not stop instantly when the oxygen atmosphere was replaced by an inert gas, but rather followed an exponential type of decay. The rate of decay appeared to be different with different types of polymers. The intensities of luminescence and the times required to reach maximum or steady state luminescence were compared with oxygen uptake data for various polymers. In general there was a qualitative, but not necessarily quantitative correlation between the luminous intensities and polymer stabilities in the presence of oxygen.
Oxyluminescence of polymers. II. Effect of temperature and antioxidants
Authors: Schard M. P. , Russell C. A. 
Published: April 2003

AbstractThe oxyluminescence of polypropylene and polyethylene stabilized with various amounts of 4,4′‐thiobis(3‐methyl‐6‐tert‐butylphenol) were studied and compared with oxygen uptake data. It was found that there was a correlation, although not linear, between the two methods. In the case of the stabilized polypropylenes, a pronounced aging effect was noticed. The oxyluminescent behavior of stabilized polyethylene was somewhat different from that of stabilized polypropylene. The temperature coefficients of the oxyluminescence of polypropylene, polyethylene, nylon 6, polystyrene, polyurethane and polymethyl methacrylate were obtained. From these data the apparent activation energies for the light‐emitting reaction were calculated. For the olefin polymers, these values are close to the activation energies of the oxidative degradation reaction obtained by other means. Both polyethylene and polymethyl methacrylate have different activation energies below their transition points as compared to higher temperature, indicating a different mode of reaction in the solid state from that occurring in the melt. An interesting transition luminescence, which was more pronounced in the absence of oxygen, was observed in the case of polyethylene.
Some thermal studies on poly(ethylene terephthalate)
Authors: Hughes M. A. , Sheldon R. P. 
Published: April 2003

AbstractDifferential thermal analysis (DTA) and thermogravimetric analysis (TGA) of poly(ethylene terephthalate) has been carried out on samples of amorphous, cold‐drawn, heat‐crystallized, and acetone‐crystallized polymer. From DTA it appears that for amorphous material a prolonged “secondary” crystallization process follows a primary process in the region of 140°C. For cold‐drawn polymer, heat treatment does not reflect differences observed in previous x‐ray diffraction studies. The TGA gives evidence that a high temperature endothermic peak observed in DTA may not be directly associated with depolymerization. With acetone‐crystallized material a high degree of acetone retention is detected.
Thermal decomposition of polysulfones
Authors: Wellisch Eric , Gipstein Edward , Sweeting Orville J. 
Published: April 2003

AbstractThe thermal decomposition of the C4, C6, and C8 polymethylene sulfones has been investigated at 275°C. under reduced pressure. The gaseous decomposition products, collected and identified by infrared and mass‐spectrometer analysis, were found to consist primarily of sulfur dioxide, olefins, alkanes, water, and hydrogen. A mechanism is proposed in which the rate‐determining step consists of a concerted attack of the sulfone group on the β‐hydrogen atom with elimination resulting in α‐olefins and a sulfinic acid. The sulfinic acid rapidly decomposes to give sulfur dioxide, hydrogen, and alkyl free radicals. The final products are formed by transfer and termination reactions of the free radicals and isomerization of the olefins in the presence of sulfur dioxide. Experimental evidence confirming this mechanism consists of rate studies of polymer decomposition whose initiation was found to be independent of polymer purity and of added free‐radical initiators. A further proof of the rate‐determining step was obtained by comparison of the decomposition products of bis‐1,4‐(butanesulfonyl)butane with those of structurally comparable sulfinic acids: 1,4‐butanedisulfinic acid and 1‐butanesulfinic acid.
Effect of surface tension in the measurement of the average normal stress at the exit of a capillary tube through an analysis of the capillary jet
Authors: Slattery John C. , Schowalter W. R. 
Published: April 2003

AbstractThe analysis of a stationary, rotationally symmetric liquid jet which leads to an expression for the average normal stress at the exit of a capillary tube is reexamined with particular attention to the effect of surface tension. The limiting case of a nearly cylindrical jet is compared with the analysis presented by Gavis and Middleman.