bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymeric ligands IV.1 Polyvinyl β‐ketoesters
Authors: Berninger C. J. , Degeiso R. C. , Donaruma L. G. , Scott A. G. , Tomic E. A. 
Published: April 2003

AbstractCopolymers were prepared by ester interchange of polyvinylalcohol with ethyl acetoacetate, ethyl benzoylacetate, and ethyl 4‐nitrobenzoylacetate. Reaction of ethyl 2,4,6‐trimethylbenzoylacetate with polyvinylalcohol yielded a homopolymer. The polymers functioned as chelate ion exchangers. Ion exchange capacities were determined for the polymer derived from polyvinylalcohol and ethyl acetoacetate.
Dynamic properties of butyl containing attrited black
Authors: Gessler A. M. , Payne A. R. 
Published: April 2003

AbstractThe dynamic modulus and loss angle of butyl vulcanizates containing both normal and attrited carbon black (HAF) have been studied over a wide strain amplitude range. Large changes are observed in the modulus with the attrition of the black. Hot milling treatment accentuates these changes. The decrease of modulus with the logarithm of the strainwork is shown to be sigmoidal in form. When the modulus is normalized between, G0, the shear modulus at very low strains and, G∞, the shear modulus at high strains, the resulting plots with respect to strainwork are independent of the concentration of the black and the condition of the vulcanizate.
Vinyl oil monomers. I. Vicinal methacryloxy‐hydroxy soy oils
Authors: Nevin C. S. , Moser B. F. 
Published: April 2003

AbstractNew vinyl oil monomers have been prepared by combining epoxidized unsaturated oils with vinyl carboxylic acids. This is accomplished by heating the reactants in the presence of free radical inhibitors and appropriate reaction catalysts. The reaction consists of cleavage of the oxirane ring followed by addition of the vinyl acid through its carboxylic group. By varying the reactants and the conditions of reaction, a large family of related, but different, vinyl oil monomers can be prepared. Vicinal methacryloxy‐hydroxy soy oil monomers are clear, yellow, medium viscosity (2000–2500 cpoise), high molecular weight (1300–1500) liquids. Chemical analyses are presented for typical preparations. The monomers readily homopolymerize by a free radical mechanism to clear, solid, thermoset resins. They are compatible with a variety of commercial vinyl monomers and form copolymers which range from highly viscous liquids through soft gels, to tough rubbery products and hard resins. Data are presented on physical properties of copolymer castings of several specific vicinal methacryloxy‐hydroxy soy oil monomers.
The effects of electron radiation on the properties of ziegler polyethylenes
Authors: Wright B. 
Published: April 2003

AbstractAn investigation has been made of the effects of electron radiation on the properties of stabilized Ziegler polyethylenes. Radiation was applied at dose levels of 0, 2, 5, 10, 25, 50, and 75 Mrad to polymers of various molecular weights and densities. The properties most affected were flow behavior and stress‐cracking resistance. Radiation reduces the melt index of the polymers rapidly and no flow is observed at doses of 10 Mrad or more. A corresponding increase in environmental stress‐cracking resistance is evident and in every case this property reaches a value of 2000 hr. at a dose of 10 Mrad. Changes in other properties are not very great until the radiation dose becomes large. At a dose of 50 Mrad, softening point is increased on the average by 7°C., yield strength is increased on the average by 140 psi, elongation is reduced to a common value of about 200% and impact strength is increased to a common value of about 20 ft. lb./in. notch. Power factor rises to a maximum as the dose is increased to 10 Mrad and diminishes at larger doses. Flex resistance, in the one case examined, diminishes as radiation dose is increased.
Ionic crosslinking of chlorosulfonated polyethylenes
Authors: Maynard John T. , Johnson Paul R. 
Published: April 2003

AbstractIt is shown that chlorosulfonated polyethylenes heated with divalent metal oxides or hydroxides and rosin acids in the presence of trace amounts of free‐radical scavengers crosslink exclusively by formation of metal–sulfonate bonds. Vulcanizate properties are independent of the nature and concentration of free‐radical scavengei, and it is suggested that these agents prevent decomposition of the sulfonyl chloride crosslinking sites, thus allowing efficient reaction with the salt‐forming components of the system. This technique allows the curing of chlorosulfonated polyethylenes in direct contact with copper and lead without development of the adhesion or discoloration usually encountered in sulfur‐containing systems.
Study of epoxy compounds. Part II. The gelation point of the epoxy resin–acid anhydride system
Authors: Tanaka Yoshio , Kakiuchi Hiroshi 
Published: April 2003

AbstractEquations are derived by means of Flory's original method for the gelation point of epoxy resin/acid anhydride/polyhydric alcohol systems containing various epoxy resins, acid anhydrides, and polyhydric alcohols. The resultant equations take no account of the reactivities of the various carboxyl, epoxy, and hydroxyl groups and are applied satisfactorily to epoxy resin/acid anhydride/polyhydric alcohol systems. The difference between the observed and calculated gelation point is about 2–3% when the acid anhydride used in HHPA and 4–5% when the acid anhydride used is tri‐ or tetrafunctional, such as TMA and PMDA. There is a little difference between resins E‐828 and E‐1001 for the gelation point. The discrepancy is beleived to be due to the reactivity difference between epoxide and hydroxyl to carboxyl groups and to the occurrence of intramolecular condensation, and it is contended that the degree of intramolecular condensation in these branching systems obtained is a function of the branch unit functionality of reactant, in this case, acid anhydride or epoxide.
Friction and deformation of nylon. II. Theoretical
Authors: Adams N. 
Published: April 2003

AbstractIt was concluded in the preceding paper that there was a significant difference between the indices m and n in the expression A = βWm and F = αWn by which the contact area A and the friction F were found to be related to the load W when nylon 610 slid on glass. A discussion of published adhesion theories of the friction of elastic bodies shows that the difference n – m is too small to be attributed to roughness of the nylon surface. It is concluded that under the contact pressures used the nylon surface was effectively smooth and that the friction of a unit area of “true” (i.e., molecular) contact between nylon and glass increased with pressure P as about P1/4. A theoretical treatment is given of the dependence of friction on load for a rough‐surfaced elastic body which covers the load range in which the surface asperities become completely flattened. It is shown that from measurements of the elastic properties of the body and feasible measurements of its surface texture one can estimate the load at which the dependence of friction on load changes from that for a rough to that for a smooth surface. Comparison with a published experiment is satisfactory.
Some aspeots of the microetructure of polyblends of poly(vinyl chloride) and butadiene–acrylonitrile copolymer rubber with and without talc fillers
Authors: Rovatti Walter , Bobalek Edward G. 
Published: April 2003

AbstractFracture and microtome sections of polyblends, prepared from varying proportions of poly(vinyl chloride) and an elastomer (with and without talc fillers) and with the use of different conditions of mixing, were examined with the electron microscope. In general, the structures observed in cut and in fracture sections were very similar when taken from the same polymer at the same reference planes with respect to direction of process‐induced orientation. Optimal tensile behavior seems to occur when the degree of mixing establishes a structure resembling a fibrous interweaving of continuous domains. Undermixing or overmixing seems to establish more random dispersions of more or less large and discrete particles of rubber in a continuous poly(vinyl chloride) phase. Introduction of fillers changes the microstructure of the fracture patterns. Particularly in polymers containing talc fillers, the influence of prior strain history on microstructure is very evident. Thirty‐eight figures are shown to demonstrate how differences in composition, mixing process, and strain history can alter the microstructure produced by fracture or cutting of the plastic.
Effect of rate and temperature on the tensile properties of double‐base propellant
Authors: McAbee E. , Chmura M. 
Published: April 2003

AbstractThe tensile properties of two cast and two extruded solid rocket propellants were studied at 25°C. and 50% R.H. over a range of failure times from 0.005 to 2500 sec. The effects of temperature were also investigated at the highest rate and at 0.1 in./in./min. over a range of −60 to 80°C. The results indicate that both temperature and rate of loading greatly affect the tensile properties of double‐base propellants.
High speed tensile testing as an index of the oxidative degradation of polyethylene resins
Authors: Meltzer Theodore H. , Supnik Ross H. 
Published: April 2003

AbstractA study was made of the tensile properties of two polyethylene resins incrementally oxidized on a two roll mill at 160°C. Changes in tensile parameters were related on a theoretical basis to the net effect of crosslinking and chain scission, and compared with solution viscosity measurements for the same materilas. It was shown that polymeric oxidative degradation was affected by molecular weight distribution and by crystallinity. In addition measurement of properties over 5 decades of time revealed a “critical velocity,” reflecting a relatively sensitive measure of degradation. High speed tensile tests provided a useful diagnostic tool for detecting early evidence of molecular decomposition in the materials studied.
High speed puncture testing of thermoplastics
Authors: Furno F. J. , Webb R. S. , Cook N. P. 
Published: April 2003

AbstractAn extensive study has been made of a broad range of polymeric materials, by the instrumented high speed puncture method. The range of strain rates prevalent in these tests has been related to the strain rates in parts subjected to normal abuse. It has been further demonstrated that at some critical test speed each material exhibited a load maximum which is accompanied by a change in the mode of failure and loss of ductility. This “critical speed” has been shown to be characteristic of the material under test.
Factors influencing izod impact properties of thermoplastics measured with the autographic impact test
Authors: Wolstenholme W. E. , Pregun S. E. , Stark C. F. 
Published: April 2003

AbstractThe standardization of notched Izod impact test data to normalized values of foot pounds per inch of notch is based on the assumption of a 1:1 increase in breaking strength with increasing notch width. This assumed relation is not supported by experimental tests on commercial thermoplastics. As notch width was increased from 1/8 to 1/4 to 3/8 to 1/2 in., nine of ten thermoplastics tested showed a decrease in normalized impact strength. Each material appears to show a characteristic loss in breaking strengths as the notch width increases. A technique developed for calibration of pendulum impact testers has been used to examine the variation of impact breaking strength in relation to the total kinetic energy of the hammer. Experimental tests show practically no change in impact strengths up to values that take 2/3 of the available hammer energy. Experimental work on the comparison of the impulse transferred by the hammer during breaking with impulse curves photographed by the Autographic Impact test show very good agreement for catastrophic breaks and fair agreement for plastic type breaks. The reduction in recorded impulse is attributed to the degrading of the sample during the plastic portion of the breaking cycle. The peak force of thermoplastics as measured by the Autographic Impact test increases as the temperature decreases from 100°C. or above to 0°C. Over the same temperature range flexural tests on small cantilever samples of these thermoplastics show the same thermal dependence for the flexural yield or permanent distortion stress. Plots of the impact peak forces and flexural yield stress at corresponding temperatures give a linear correlation. Each thermoplastic material exhibits a unique relation for this correlation between impact yielding and flexural yielding. This correlation between the impact and flexural tests over the range of temperatures is the first known experimental indication of a direct relation between impact properties and standard physical tests.
Rapid bursting of tubular specimens
Authors: Noyes R. B. 
Published: April 2003

AbstractBurst tests on thin wall circular cylinders of aluminum, brass and magnesium alloys, mild steel and polymethylmethacrylate plastic are described in which stress and strain are measured at impact velocities of 14–31 ft./sec. The apparatus consists of an hydraulic cylinder and piston assembly attached to the inside of the specimen, with a falling weight producing a pressure pulse. Measurement problems inherent in the technique are analyzed: e.g., local instability leading to blister formation. An increasing amount of uniform deformation occurs in the specimen as strain rate is increased.
Techniques for studying strain rate effects in brittle materials
Authors: Abbott B. W. , Cornish R. H. , Weil N. A. 
Published: April 2003

AbstractTechniques for studying brittle fracture over a strain rate range of 10−7–101 in./in./sec. and at temperatures from 75 to 1800°F are discussed. Techniques for achieving a uniaxial tensile stress in prismatic bars via a reflected stress wave method at strain rates up to 103 in./in./sec. at room and elevated temperatures are presented. Results of the aforementioned effects in flexure, and experimental verification of the stress‐time‐position history for the stress wave loading technique are presented along with applicable theoretical explanations. Applications of the above techniques to a broader spectrum of brittle and semi‐brittle materials are described.
Effect of strain rate on the viscoelastic properties of high polymeric fibrous materials
Authors: Dogliotti Eugene C. , Yelland William E. C. 
Published: April 2003

AbstractStress‐strain measurements have been made at a relatively low strain rate (100%/min.) and at relatively high strain rates (approximately 260 × 103%/min.) on a series of high polymeric materials of different chemical composition in textile yarn form. The series comprises the following classes of materials: polyacrylic, polyamide, polyester, polymodacrylic, polyolefin, polypeptide, polyurea, polyurethane, polyvinylidene chloride, rubber, and glass. The yarns, with a few exceptions, were conventional continuous filament, low twist structures of varied filament count and denier. Polyvinylidene chloride was tested both as a monofil and also in the form of a slit film. Polyethylene was tested as a monofil. Two polyurethanes and the rubber were tested as monofils with and without cotton covering. From the results of the stress‐strain measurements there were calculated values for the following properties at two strain rates: tenacity and elongation at break, work‐to‐break, and initial modulus. The effects of increased strain rate on these properties are shown. In general, increased strain rate increases the tenacity and initial modulus. These changes are usually, but not always, accompanied by decreases in elongation at break, so that the work to break may either decrease or increase with increasing strain rate. The physical form in which the yarns were tested (denier, number of filaments, conventional yarns versus slit film type) appeared to have only slight effect on their behavior at different strain rates. However, the chemical nature of the polymer molecules and their physical organization within the yarn filaments both have appreciable effects on yarn behavior at different strain rates. The first effect, that due to chemical nature, is exemplified by silk. The behavior of this natural polypeptide, which contains an appreciable number of side chains attached to the main polymer chain, differs markedly, as the strain rate is increased, from the behavior of polyamides which do not contain such side chains. The side chains evidently tend to keep the main polymer chains apart and thus the interchain forces in the polypeptide differ greatly from the interchain forces in polyamides which do not have such side chains. The second effect, that due to the physical organization (crystallinity and degree of orientation) of polymer molecules within a fiber, is demonstrated by a comparison of the behavior of undrawn and regular nylon at low and high strain rates. The stress‐strain behavior of the other polymers in yarn form at different strain rates is discussed in the light of their chemical structure and macromolecular organization.
Single and repeated snatch loading of textile yarns, and the influence of temperature on the dynamic mechanical properties
Authors: Swallow J. E. , Webb M. W. 
Published: April 2003

AbstractYarns of nylon and polyethylene–terephthalate were subjected to snatch loadings of quarter period 5 × 10−2 sec. and stress amplitudes up to break, by impacting at several known levels of energy. Force developed was measured as a function of time by means of a capacitance gauge, and the extension by photographing the movement of a small torch attached to the yarn. The equivalent linear modulus, calculated from the period of longitudinal oscillation at low energy input, agreed broadly with the initial modulus of the dynamic load‐extension curves. In repeated impact at a given energy level, the total deformation increased logarithmically with time, but the extension attributable to individual impacts decreased. There was a corresponding progressive increase in dynamic tension, but the breaking tension was not apparently affected either by the number of previous impacts or by the energy level. Breaking loads of a nylon yarn, reached in 10−2, 10, and 103 sec., were compared at temperatures from 20 to 250°C. Tenacity decreased with temperature at a rate depending on the time to break, but the tenacity at a temperature of about 240°C. was substantially independent of rate of loading. Strain‐time relationships, obtained at various temperatures using a photoelectric technique, were compared and analysed.
Novel curing systems for chlorosulfonated polyethylene
Authors: Nersasian A. , King K. F. , Johnson P. R. 
Published: April 2003

AbstractPolyfunctional alcohols, acyclic, cyclic, and heterocyclic imines, and organotin oxides have been studied as crosslinking agents for chlorosulfonated polyethylene. Mechanisms for the crosslinking reactions involving the sulfonyl chloride moiety have been proposed. Differences in curing activity have been correlated with structural modifications of the curing agents consistent with classical chemical reactions for nonpolymeric systems. Of the curing systems examined, the polyols provide nontoxic, low cost, safe‐processing formulations offering excellent physical properties which have found use in practical commercial applications.
Generalized approach to adhesion via the interfacial deposition of amphipathic molecules. III. Adhesion of polyethylene to stainless steel
Authors: Schonhorn Harold 
Published: April 2003

AbstractOriented monolayer adhesives of stearic acid have been employed to bond polyethylene to stainless steel. Bonding time, bonding temperature, and rate of peel are several of the parameters that here varied to determine their effect on the final peel strength. Peel strengths of about 90 lb./in. width were obtained for monolayer coated specimens. When the specimens were fabricated properly, only cohesional failure of the polyethylene resulted. Irradiation of the bonded specimens resulted in considerable lowering of the peel resistance of the nonmonolayer coated specimens, relatively small differences being noted for those prepared with the oriented monolayer adhesive.
Stress relaxation in molten polymers. IV
Authors: Mussa C. , Sacerdote P. , Guglielmino P. , Tablino V. 
Published: April 2003

AbstractAfter a survey of suggested analytical methods, data are given for ten polymer samples (high and low pressure polyethylenes, atactic and isotactic polypropylenes, and of natural rubbers). It appears that the suggested methods of plotting the stress relaxation data after cessation of steady flow, as well as the quantities defined from such analysis, in the case of the given polymers can yield qualitative and semiquantitative information on such structural features such as average chain length, polydispersity, chain regularity, long branching, and crosslinking.
Rheologic behavior of epoxy resins in the transition region
Authors: Theocaris Pericles S. 
Published: April 2003

AbstractMaster curves of log Q(t/K) against log (t/K) were constructed from experimental data on creep compliance, relaxation modulus, stress‐optical and strain‐optical coefficients of two types of epoxy resins at a series of temperatures in the transition region. The characteristic creep or relaxation time K for each temperature was defined and tabulated. The master curves were fitted to the reduced equation of the Gauss error integral form and the following characteristic parameters were calculated: Q1, the glassy‐state parameters (creep compliance, relaxation modulus, stress‐optical or strain‐optical coefficients); Q2, the rubbery‐state parameters; Td, the distinctive temperature; Kd, the characteristic creep or relaxation time at Td; and the parameters ht and hg of the steepness of master curves at the transition and glassy regions, respectively. The investigation was extended to the determination of the distribution functions of mechanical and optical retardation and relaxation times L (log τ) and H (log τ), respectively, representing the differential contribution to instantaneous compliance, stress‐optical or strain‐optical coefficients associated with retardation times and instantaneous modulus, stress‐optical or strain‐optical coefficients associated with relaxation times.
Photopolymérisation du nitrile acrylique en présence des sels de lanthane
Authors: Simionescu Cristofor , Feldman Dorel , Oprea Spiridon 
Published: April 2003

AbstractData are given for the photopolymerization of acrylonitrile in the presence of some lanthanium salts, as initiators of the polymerization. The activity of these salts with respect to the photopolymerization of acrylonitrile indicates the following series: LaCl3 · H2O > La2(SO4)3 · 9H2O > La(NO3)3 · 6H2O > La(CH3COO)3. The kinetics of the process have also been considered.
Study of polymers applicable to insulation systems
Authors: Torossian K. A. , Jones S. L. 
Published: April 2003

AbstractIn recent years thermosetting polymeric systems have been used extensively as binders in electrical insulation and composite plastic structures with excellent success. However, such properties as post‐cure gassing, thermal stability, and high temperature bond strength have always been stumbling blocks for the insulation engineer. Experience has shown that these properties can ultimately affect the dielectric endurance of an insulation when subjected to high voltage stresses. The above‐mentioned problems are generally controlled by the organic binders present in the insulation. Test methods have been developed whereby the behavior of the polymers under certain conditions can be predicted, thus increasing the effectiveness of the design engineer.