bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rotating spherical interlayer (RSI) measurement of the dynamic mechanical properties of elastomers
Authors: Kaelble D. H. 
Published: April 2003

AbstractAn analysis of simple shear in a rotating spherical interlayer is presented. The theory provides design criteria and operating equations for a new method of measuring the dynamic mechanical properties of soft viscoelastic polymers. The storage component of the dynamic shear modulus G′(ω) = 3F1hm2/2πr4(3 sin ϕ + sin3ϕ) (ΔXt − K1F1) and the loss tangent than δ = [F2(ΔXt − K1F1) − K2F1F2]/[F1(ΔXt − K1F1)− K2(F2)2] are expressed in terms of the inner radius r, thickness, h, and are angle ϕ of sample extending from the rotational equator; the biaxial dynamometer compliances K1, K2; the imposed dynamometer displacement ΔXt; and the spherical interlayer storage and loss forces F1, F2. New instrumentation involving a rotating spherical interlayer (RSI) transducer and a rotational accessory to the Instron provides measurements from 0.001 to 45 cycle/sec at temperatures from −50° to 200°C. A comparison of RSI data, treated by time–temperature superposition, and literature values of dynamic response in polyisobutylene confirms both theory and method.
Transparent barrier resins with high nitrile content
Authors: Hughes E. C. , Idol J. D. , Duke J. T. , Wick L. M. 
Published: April 2003

AbstractThe effect of 30–49 wt‐% nitrile group content on the properties of copolymers is demonstrated. The nitrile is furnished by either acrylonitrile or methacrylonitrile. The exceptional resistance of such high nitrile content resins to the passage of gases and of solvents is shown and variations therein demonstrated for different comonomers. Transparent, tough, grafted polymers of good color are described which retain these properties. These qualities, combined with low second‐order transition temperatures and adequate heat deflection temperatures, provide polymers of interest wherever containment and barrier are desired. Bottles, thermoformed containers, etc., could benefit from the use of some of the polymers described.
Thermal analysis of nitro‐substituted epoxide polymers
Authors: Fleming Gerald J. 
Published: April 2003

AbstractThe thermal properties of a number of nitro‐substituted and analogous nonnitro‐substituted expoxide polymers were investigated. Dramatic increases in char yield and decreases in maximum rate of weight loss were observed for the nitro‐substituted systems compared to their nonnitrated analogs. These effects were enhanced when highly functional and highly aromatic epoxide resins were used. The sample size and heating rate employed had pronounced effects upon the amount of char formed during thermal degradation. Analysis of char residues indicates heteroring formation for the nitro‐substituted systems during pyrolysis.
Cellulose graft copolymers. I. Graft copolymerization of ethyl acrylate with γ‐irradiated cellulose from methanol–water systems
Authors: Nakamura Yoshio , Hinojosa Oscar , Arthur Jett C. 
Published: April 2003

AbstractEthyl acrylate was graft‐copolymerized with γ‐irradiated, purified cotton cellulose from methanol–water systems. The accessibility of the free radicals in the irradiated cellulose to water, methanol, ethyl acrylate, and methanol–water solutions was determined by electron spin resonance spectroscopy. The maximum scavenging of the radicals was recorded with the irradiated cellulose was immersed in methanol–water solution which had a composition of 50/50 vol‐%. When ethyl acrylate was added to methanol–water solution (50/50 vol‐%), maximum grafting on the irradiated cellulose occurred at a concentration of ethyl acrylate of about 20 vol‐%. As the concentration of ethyl acrylate was decreased, maximum grafting occurred in solutions containing less than 50 vol‐% methanol. It was also noted that maximum grafting of ethyl acrylate in methanol–water solutions to irradiated cellulose occurred at boundry conditions, that is, conditions where the ternary mixture was still one phase, slightly different from compositions which caused the mixture to separate into two phases. From methanol solution, maximum grafting occurred at a concentration of ethyl acrylate of 80 vol‐%. The extent of grafting from methanol was less that obtained from methanol–water solutions at lower concentrations of ethyl acrylate. The accelerative effects of water was considered to be due to the Trommsdorff effect.
Study of polyethylene blends by differential scanning calorimetry
Authors: Sato Tetsuo , Takahashi Mikio 
Published: April 2003

AbstractThe melting behaviors of linear and branched polyethylene blends were studied using a Perkin‐Elmer DSC‐1B differential scanning calorimeter. Three endothermic peaks were occasionally observed in the DSC thermogram on polyethylene blends which had not been subjected to any isothermal annealing. The nature of the third intermediate temperature peak is discussed in relation to the prior cooling rate, the blend composition and the molecular structures of both components. The results appear to indicate that the intermediate peak is associated with the fusion of the hybrid crystallites of linear and branched polyethylenes. These hybrid crystallites seem to be formed on the rapid cooling of lean linear polyethylene blends. Blends containing low molecular weight branched polyethylene seem inclined to form the hybrid crystallites.
Electron beam irradiation of an ultrahigh molecular weight polyethylene resin in air
Authors: Brenner W. , Adler A. , Oswald H. J. , Turi E. A. 
Published: April 2003

AbstractHigh molecular weight linear polyethylene has been irradiated in the solid state by high energy electrons. The irradiated samples were characterized by differential scanning calorimetry, solubility properties, and stress‐strain measurements. A failure mechanism is proposed for the observed embrittlement of the polymer.
Poly‐2‐oxazolidones as cryogenic adhesives
Authors: Sandler Stanley R. 
Published: April 2003

AbstractAdhesives data are presented at −320° to +400°F for adhesion to aluminum or stainles steel to indicate that poly‐2‐oxazolidone‐type adhesives give poor results when conpared to epoxy amine, polyurethane prepolymer amine, or a mixture of the latter two resins.
Characterization of sulfur‐cured styrene–butadiene copolymer rubbers and their polybutadiene blends
Authors: Clark J. K. , Scott R. A. 
Published: April 2003

AbstractDissolution of sulfur‐cured, carbon black‐loaded copolymers and their blends with cis‐1,4‐polybutadiene (PBD) are brought about by boiling with o‐dichlorobenzene which contains a small amount of 2,2′‐dibenzamidodiphenyl disulfide. The resulting slurries are subjected to a sequence of separations which include high‐speed centrifugation to remove solids, and solvent precipitation followed by filtration to isolate the precipitates. The precipitates are washed with solvent to remove soluble organic materials followed by carbon disulfide washing to dissolve the polymers. Cast films of the polymers are obtained by evaporating the carbon disulfide washings onto sodium chloride discs. The infrared spectra of the cast films of these preparations are very similar to those of their respective polymers prior to loading and curing. Calculations for relative concentrations of bound styrene and PBD microstructures permit nominal identification of the kinds of styrene–butadiene rubber and the amounts of cis‐1,4‐PBD used in a cured rubber formulation. Absorption bands used are near 3.35 μ for cis‐1,4‐PBD, 6.65μ for bound styrene, 10.35 μ for trans‐1,4‐PBD; and 11.0 μ for vinyl‐1,2‐PBD. Efforts are being made to improve the data by using a grafting infrared instrument and also to extend the calibrations to include other rubber blends.
Unsteady flow of viscoelastic fluids
Authors: Chong J. S. , Vezzi D. M. 
Published: April 2003

AbstractTheoretical solutions for unsteady flow of a three constant Oldroyd fluid and a second order fluid under several different flow conditions of practical interest are obtained. The response of these fluids to suddenly applied external force is investigated in each case. Without using the stick‐slip boundary condition at the wall, it is possible to show that pressure oscillation occurs with both fluids under a certain case.
The analysis of polyurethane foams. I. Identification of components
Authors: Dawson B. , Hopkins S. , Sewell P. R. 
Published: April 2003

AbstractA scheme of qualitative analysis is presented for the identification of the constituents of polyurethane foam products, or indeed polyurethane‐type materials in general. Elastomeric and cellular polyurethanes are analyzed by hydrolysis to simpler compounds which are then separated and identified. The methods of identification employed include infrared and nuclear magnetic resonance spectroscopy, gas chromatography, and thin‐layer chromatography.
Antioxidant effects in PVC plasticized with DIDA
Authors: Darby J. R. , Touchette N. W. , Sears J. K. 
Published: April 2003

AbstractAntioxidants such as bisphenol A (BPA) have long been recommended for retention of physical properties on oven‐aging of PVC plasticized with certain plasticizers. We have shown how BPA inhibits oxidative fragmentation of plasticizers such as diisodecyl adipate (DIDA) and thus decreases apparent volatility, and how it improves retention of modulus, elongation, and low temperature flexibility. Low concentrations are more beneficial than either zero or high concentrations, especially on longer aging. At higher concentrations, although the plasticizer is retained in the PVC, it becomes less efficient at low temperature, and low‐temperature flex is impaired while elongation is preserved. DIDA exudes during oven‐aging unless oxidation occurs to prevent it. When BPA is present, exudation is worst at the most efficient concentrations of antioxidant. This appears to be the normal incompatibility of DIDA at 105°C which is permitted by the antioxidant. On oxidation, the dielectric constant of DIDA rises into the 4–8 range, signifying compatibility with PVC, and the DIDA does not exude.
Heat stability of chemically crosslinked polyethylene
Authors: Narkis M. , Tobolsky A. V. 
Published: April 2003

AbstractHeat stability in air of chemically crosslinked polyethylene loaded with medium thermal (MT) carbon black was studied as a function of temperature and carbon black content. Weight loss at 200° to 250°C is practically independent of the carbon black concentration. Modulus–temperature curves are changed with various heat treatment periods at 225°C. These curves show that the rubbery modulus (amorphous state) increases with increasing the heating period, while the modulus of the partially crystalline polymer goes through a minimum and then increases. Continuous stress‐relaxation and intermittent stress curves show the existence of degradation and crosslinking reactions, the latter becoming more important at higher temperatures or longer times. The degradation reaction is practically independent of the carbon black content while the crosslinking reaction at 225°C is faster with increasing MT black concentrations. It is concluded that reasonable heat stability, in the crosslinked polyethylene compounds studied, can be obtained at temperatures lower than 150°C.
Effect of multiple feeds on a termination‐free polymerization in continuous stirred tank reactors
Authors: Teaney F. G. , Anthony R. G. 
Published: April 2003

AbstractThe effect of monomer and initiator feeds to each of a series of continuous stirred tank reactors (CSTR) on the molecular weight distributions, average molecular weight, polymer production rate, and initiator and monomer conversions is studied for the termination‐free polymerization system. For initiator feed concentrations less than 0.001 mole/liter, the distribution becomes narrower as the polymer progresses from reactor 1 to reactor 3. But for concentrations of initiator of 0.01 mole/liter, the distribution may be broadened from reactor 1 to reactor 3. The broadening of the distribution results in the production of a lower molecular weight polymer.
Friction of polymer films. III. Migration of lubricants
Authors: Owens D. K. 
Published: April 2003

AbstractThe migration of the lubricant stearamide to the surface of vinylidene chloride–acrylonitrile copolymer coatings on regenerated cellulose film was studied by measuring the effect of heating the coatings on friction and critical surface tension. The surface quantity of stearamide was maximum at a heating temperature of 65°C. Above this temperature stearamide was lost from the surface. Up to 65°C the migration of lubricant obeyed first‐order kinetics and the activation energy was calculated. Below 65°C diffusion to the surface appears to be the controlling process, while above 65°C evaporation from the surface is probably the controlling process.
Conditioning polytetrafluoroethylene surfaces for use in vascular prostheses
Authors: Miller M. L. , Postal R. H. , Sawyer P. N. , Martin J. G. , Kaplit M. J. 
Published: April 2003

AbstractPolytetrafluoroethylene surfaces have been treated to reduce thrombogenicity in order to make them suitable for use in prosthetic devices that come in contact with blood. This was done by first etching the surface with potassium in liquid ammonia to produce double bonds and then using these double bonds as sites for grafting on polyacids or as sites for chemical reactions. Tubes so treated were tested for thrombo‐genetic activity by implantation in the thoracic aorta or inferior vena cava of dogs. These tests showed that the thrombogenicity of a polytetrafluoroethylene surface can be reduced by attaching negatively charged groups provided the surface concentration of these groups is not too high (order of 1–2 × 10−6 equivalent per cm2 geometric area) and provided the distribution of these groups is uniform. Sulfonic acid groups obtained by chlorosulfonation and carboxyl groups attached by grafting tert‐butyl crotonate and hydrolyzing to crotonic acid were effective. Long chains of poly(acrylic acid), poly‐(ethylenesulfonic acid), and poly(vinyl alcohol) sulfate were less effective.
Molecular weight distribution of polystyrene and of butadiene–styrene copolymers prepared in emulsion systems
Authors: Uraneck C. A. , Burleigh J. E. 
Published: April 2003

AbstractPolystyrene and butadiene–styrene copolymers (SBR) were prepared in emulsion systems with a homologous series of commercial mercaptan modifiers. The molecular weight distribution (MWD) of the sets of polymers changed in a consistant manner when the regulating index of the mercaptan was relatively low. However the shape of the MWD curves appeared distorted in comparsion to theoretical curves when the modifier depleted rapidly and when divinylbenzene was present in the system. The divergence from the theoretical curve is attributed to a higher degree of branching in the high molecular weight fractions. Differences in MWD of SBR made with n‐ and tert‐ dodecyl mercaptans was marked. Notable differences were also found for SBR 1500 samples from the industry at random, but only slight differences were seen in a set of SBR 1503 samples. This study shows how the MWD of polymers prepared in emulsions can be varied simply by use of modifiers with different regulating indexes.
Temperature dependency of bound water of cellulose studied by a high‐resolution NMR spectrometer
Authors: Ogiwara Yoshitaka , Kubota Hitoshi , Hayashi Shoichi , Mitomo Noriko 
Published: April 2003

AbstractThe widths at half‐value of high‐resolution NMR spectra of bound water of cellulose were studied in relation to the temperature change. Two points were made clear: First, the amount of bound water of the cellulose sample can be pointed out with higher accuracy the lower the temperature of the measurement. Second, it is possible to determine in a simple manner the boundary temperature Tc at which water molecules become bound by the cellulose. Tc is characteristic of the cellulose sample of a given water content and corresponds to the glass transition temperature of the water‐containing sample. The measurements appear to be readily applicable to other hydrophilic polymers.
Concentration dependence of the diffusion coefficient in polymer solution and molecular weight distribution determined by the diffusion method
Authors: Matsuda Hideomi , Aonuma Hidehiko , Kuroiwa Shigetaka 
Published: April 2003

AbstractThe effects of the concentration dependence of the diffusion coefficient of a polymer solution (polystyrene in benzene and cyclohexane) in determining molecular weight distribution by the diffusion method are briefly discussed. The value of the ratio Dm0/DA0 in a good solvent was found to be close to 1.0 for a polydisperse polymer and less than 1.0 for monodisperse polymers. Molecular weight distribution curves of the polydisperse sample were obtained by the diffusion method in cyclohexane and benzene, respectively. The molecular weight distribution curve obtained for the polymer used in benzene solution looked as if the polymer had a narrow molecular weight distribution. The phenomena cited above were interpreted in the light of the concentration dependence of the diffusion coefficient of polymer solutions.
Thermal analysis of compounded poly(vinyl chloride)
Authors: Dunn P. , Ennis B. C. 
Published: April 2003

AbstractDifferential thermal analysis of mixtures of poly(vinyl chloride) and dioctyl phthalate shows a compound endothermic peak due to decomposition of both polymer and plasticizer. The thermal behavior of other plasticizers is similarly affected in the presence of poly(vinyl chloride). The addition of zinc oxide or ferric oxide decreases the thermal stability of the mixture and, under isothermal conditions, a resultant induction period allows the estimation of an activation energy for the dehydrochlorination of poly‐(vinyl chloride) and of the relative effectiveness of thermal stabilizer systems.
Comparative gel permeation chromatography calibration techniques in oxidative coupling polymerization
Authors: Revillon A. , St. Pierre L. E. 
Published: April 2003

AbstractGel permeation chromatography was utilized in measuring the kinetics of the oxidative coupling polymerization of 2,6‐dimethylphenol. The elution curves at the early stages of reaction were analyzed by two methods of calibration, specifically by comparison to the elution times of oligomers up to the 6‐mer level, and by the classical counts method. The two methods give similar results, both indicating a polymerization pattern of the general condensation type and increasing dispersity of molecular weight with degree of polymerization.
Automatic recording capillary viscosimeter with dilution
Authors: Gramain Ph. , Libeyre R. 
Published: April 2003

AbstractA capillary viscosimeter with automatic determination and recording of flow times of liquids up to 200°C is described. This viscosimeter, which is specially suited for studies of polymeric solutions, includes an automatic dilution system and determines intrinsic viscosity with a precision better than 0.01%.
Thermodynamic description of relaxation phenomena in polymers
Authors: Bartenev G. M. , Zelenev Y. V. , Borodin I. P. 
Published: April 2003

AbstractThe analysis of various deformations of an ordinary elastic body and a highly elastic body accompanied by temperature changes shows that, in distinction to isothermic conditions, under adiabatic conditions the dynamic characteristics of a polymer in a highly elastic state depend on the amplitude of the applied stress (in particular, their position on a frequency or temperature scale), which is associated with the entropic nature of the highly elastic deformation.When describing the relaxation phenomena caused by the response of the system of interacting kinetic units to the external perturbation, the nonequilibrium thermodynamics relationship between the “flow” and the “generalized force” is nonlinear even at small deviations from the equilibrium state. In this case the dependency of the kinetic factor on the response can be presented by eq. (40).Considered herein were such particular relaxation phenomena as creep and stress relaxation. The calculated dependencies agree well with the experimental data.
Molecular structure of chain‐extended polymeric diols
Authors: Randall J. C. , Hamner W. F. , Taylor H. A. 
Published: April 2003

AbstractThe molecular structures of a series of chain‐extended polycaprolactone diols were studied by nuclear magnetic resonance (NMR) and conventional wet chemical techniques. Hydroxyl end group and per cent nitrogen values were obtained by phthalation and automated micro‐Dumas techniques, respectively. The value of the NMR technique is demonstrated is demonstrated in providing information regarding the total structure of the polymer. Molecular weight and per cent nitrogen values obtained by this procedure for most samples agree better than 10% with results obtained by the chemical methods.
A rheological characterization of SBS block copolymers
Authors: Arnold K. R. , Meier D. J. 
Published: April 2003

AbstractThe dynamic viscosities of styrene–butadiene–styrene (SBS) block copolymer melts with different end‐ and midblock sizes are given as a function of frequency at several different temperatures. The data exhibit two distinct regions, a high frequency region where the response is typical of thermoplastics and a low frequency region where the viscosity continually increases with decreasing deformation rates. These results are successfully explained in terms of the formation of polystyrene domains in the low frequency region. The correlations given for the rheological properties should provide additional insight to the processing of these materials.
The reaction of activated vinyl compounds with cotton cellulose via internal catalysis
Authors: Rowland Stanley P. , Brannan Mary Ann F. 
Published: April 2003

AbstractThe reactions of a variety of activated vinyl compounds with cotton cellulose fabric containing quaternary ammonium hydroxide substituents were explored. Each reaction, catalyzed by the basic groups in the cellulose, was followed to or near the point of leveling off. The results are analyzed and discussed in terms of accessibility of the cellulosic compositions and in terms of the efficiency of the quaternary ammonium substituents as catalysts for the addition reactions. Estimates of relative forward rate constants (kf) and equilibrium constants (K) for the reactions were made. The values of kf for reactions of the vinyl compounds with the quaternary ammonium celluloses show a relative order which is similar to that for the reactions of the vinyl compounds with simple alcohols. Evidence is presented to indicate that, in some cases, the addition of vinyl compounds is accompanied by anionic‐catalyzed graft polymerization.
A two‐capillary viscosity method monitored by an analytical balance
Authors: Almin Karl E. , Swenson Harold A. 
Published: April 2003

AbstractBy the simultaneous use of two capillaries, one for solution and one for solvent, and determination of the weight difference of the effluxing liquids with an analytical balance, it is possible, without time measurement, to determine the relative viscosity of a solution with high accuracy. Nylon capillaries were used in the experiments. The equation necessary for calculation of the relative viscosity is derived. The method is particularly useful for very dilute polymer solutions and for the study of low molecular weight substances and lends itself to study of the corrections common in capillary viscometry. Literature values for glucose were confirmed with the method, but low values were found for sodium chloride. The use of bundles of capillaries makes it possible to study the boundary between solvent and solution and to study the possible migration of polymer molecules, in terms of size, toward or away from the walls under conditions of capillary flow. The method can also be used for studying viscous properties of liquids that vary with time.