bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calcium stearate–stearic acid as lubricants for rigid poly(vinyl chloride) (PVC). Capillary rheometer measurements and extrusion properties
Authors: Fredriksen Odd 
Published: April 2003

AbstractCapillary rheometer measurements show that stearic acid can be characterized as a normal lubricant. If the content of stearic acid is increased in rigid PVC formulations, the melt viscosity will decrease. This leads to a corresponding increase of shear rate and volumetric flow rate. The influence of calcium stearate is opposite to the normal characteristic of a lubricant. Increasing amounts of calcium stearate lead to an increased melt viscosity and a decreased shear rate and volumetric flow rate. In the extrusion of rigid PVC, the apparent “lubricating” effect of calcium stearate is probably due to the increased friction with resulting heat evolution and higher mass temperature, leading to a decreased viscosity of the plastic melt. This is in agreement with the results of the extrusion experiments. Both mass temperature and power consumption decrease when stearic acid is added and increase when calcium stearate is added to the formulation.
Reaction of SO2 and NO2 with polymers
Authors: Jellinek H. H. G. , Flajsman F. , Kryman F. J. 
Published: April 2003

AbstractA number of polymers have been exposed to SO2 and NO2 gas under various conditions. Chain scission, crosslinking reactions, and changes in infrared spectra have been noted. All polymers suffer some deterioration, which may be considerable with exposure over long periods of time. Elastomers form a separate group, being appreciably more susceptible to these gases than saturated polymers; however, they are still more sensitive to ozone.
Viscosities of moderately concentrated solutions of polyethylene in ethane, propane, and ethylene
Authors: Ehrlich Paul , Woodbrey James C. 
Published: April 2003

AbstractThe viscosities of moderately concentrated solutions of low‐density polyethylenes in ethane, propane, and ethylene have been measured at low shear rate in the temperature range of 150–250°C and in the pressure range of about 15000–30000 psi. Within the precision of the measurements, the relative viscosity is independent of pressure over the range investigated but increases as the solvent is changed from propane through ethane to ethylene. The activation energy for the relative viscosity in ethane varies from about 0.5 to 2.5 kcal/mole as the concentration changes from 5 to 15 g/dl. Effects of polymer concentration and molecular weight on solution viscosity in ethane at 150°C have been determined, and all of the data can be represented by a single straight‐line plot of the logarithm of relative viscosity versus the intrinsic viscosity (in p‐xylene at 105°C) times concentration. This simple relation is valid over wide ranges of polymer concentration and molecular weight and over more than two orders of magnitude of relative viscosity. The solution viscosities of the polyethylenes in the three supercritical fluid solvents used appear surprisingly low at first sight. This behavior is partly a result of the low solvent viscosities but also might mean that the polymer has an abnormally low segmental friction factor compared to that in solutions under more familiar conditions.
Solubilization of calfskin collagen in citrate buffer with the use of automated equipment
Authors: Kahn Leo D. , Witnauer Lee P. 
Published: April 2003

AbstractAn automated collagen solubilizing apparatus that maintains constant electrolytic conditions during solubilization is described. It was used in solubilization of 6.95% of a calfskin corium as monomeric collagen in citrate buffer at pH 3.44 and ionic strength of 0.44 and a temperature of 8°C. It is shown that this is the limit of solubilization for undenatured collagen in this buffer.
Structure and properties of extruded polyethylene film
Authors: Desper C. Richard 
Published: April 2003

AbstractA series of low‐density polythylene extruded films was examined quantitatively by the birefringence, infrared dichroism, and x‐ray pole figure techniques. The birefringence ranges from mildly positive to mildly negative with increasing severity of quenching conditions. The x‐ray data show that the birefringence is largely due to the contribution of oriented crystallites, the amorphous orientation being quite low. The crystal orientation functions suggest equal degrees of a and c axis orientation parallel to the machine direction at low quenching rates, and increasing a axis orientation as the quenching rate increases, coupled with a shift in the c axis from parallel to perpendicular orientation. These results are confirmed by infrared dichroism data. The relative degree of a and c axis orientation ultimately reached is intermediate between that predicted by Keller's type I and type II models, but approximates the orientation previously observed in laboratory films prepared by oriented crystallization at 100% elongation. The crystalline orientation may be explained by the modified row orientation structure of Keller and Machin. However, the data can also be reconcilled with that of spherulitic entities observed in samples crystallized at 20‐50% stretch. It is suggested that these spherulites may possess a combination type II and screw dislocation morphology in the equatorial and polar regions, respectively. Such a structure differs from the row structure in that the latter implies that the amount of polar material is negligible compared to the equatorial material. It is recognized, however, that orientation data cannot unambiguously decide between these alternatives.
Disubstituted p‐phenylene monomers. α‐methyl‐ and α‐phenyl‐vinyl derivatives of benzene, biphenyl, p‐terphenyl, and p,p′‐diphenoxiybiphenyl
Authors: Rosser Robert W. , Neville Roy G. 
Published: April 2003

AbstractThe high‐yield syntheses of bis [p‐(α‐methylvinyl)] monomers of benzene, biphenyl, p‐terphenyl, and 4,4′‐diphenoxybiphenyl are reported. Also described are the syntheses of new bis[p‐(α‐phenylvinyl)] monomers of biphenyl, p‐terphenyl, and 4,4′‐diphenoxy‐biphenyl. Infrared spectral data for the diolefinic monomers and their precursors are presented, together with brief details for the polymerization of the diolefins by means of free radical and Lewis acid catalysts.
Studies on dry spinning. I. Fundamental equations
Authors: Ohzawa Yoshiyuki , Nagano Yutaka , Matsuo Tatsuki 
Published: April 2003

AbstractOne difficulty in analyzing the state of filament in the dry spinning process is that in the boundary conditions required to solve the equations of mass, momentum and energy which are derived on the consideration of balance with respect to infinitesimally small element are not given a priori. The equations which include these boundary conditions in themselves are derived by considering mass, momentum, and energy balances with respect to the entire cross section of filament. These additional macroscopic equations are simplified to a great extent by assuming the flat velocity profile through the cross section of filament. Besides, in the steady state, these macroscopic equations are modified to give the equations of average solvent content, spinning tension, cross‐sectional area, and average temperature. When the spinning conditions are given and the physical constants are measured for a given polymer and solvent system, it becomes possible to calculate the state of filament by solving these microscopic and macroscopic equations simultaneously without resorting to actual spinning.
Influence of molecular weight distribution on the elasticity and processing properties of polypropylene melts
Authors: Mieras H. J. M. A. , Van Rijn C. F. H. 
Published: April 2003

AbstractIn a study of the flow behavior of polymer melts a semi‐empirical viscometric equation has been used which contains an elasticity parameter relating the shear dependence of the viscosity to the normal‐stress effect. The way in which both these effects are influenced by the molecular weight distribution of the polymers investigated is shown, and the influence of melt elasticity on polymer processing behavior is discussed. From previously published viscosity data the elasticity parameter has been determined for a number of polypropylene grades, and the possibility of classifying these grades according to a characteristic time constant is indicated.
Adhesion behavior of nylon tire cord/adhesive/rubber systems
Authors: Iyengar Y. 
Published: April 2003

AbstractIn static and dynamic adhesion tests, the behavior of nylon tire cord/resorcinol‐formaldehyde–latex (RFL) adhesive/rubber systems was shown to be strongly influenced by the dipping and curing conditions, cord size, and the thickness of rubber layer adjacent to cords. The nature and extent of these effects were different in three types of adhesion tests which differed in stress concentrations they induced at the cord–rubber interface. The influence of stress concentration due to increased cord size was clearly seen in dynamic adhesion tests where the peel strengths of two‐ply cord/rubber samples were measured after flexing them under tension over a pulley for predetermined periods at 230°F. In these tests, the adhesion of samples with large cords weakened more rapidly than that of small cords. The static adhesion level attained with nylons 6 and 66 and other polyamide fibers was strongly dependent on the conditions (time, temperature) under which the RFL adhesive was applied and cured. At any given exposure, adhesion initially increased rapidly with the RFL curing temperature and attained a maximum above a temperature which is characteristic of the polyamide. For nylon 66, optimum adhesion was attained with different combinations of RFL curing temperatures (390–460°F) and times (20–120 sec). Finally the adhesion of nylons 6 and 66 is discussed from thermodynamic considerations based on entropy change.
Ethylene‐propylene terpolymers with conjugated double bonds
Authors: Sonnenfeld R. J. , Kahle G. R. , Buck O. G. 
Published: April 2003

AbstractA study was made of ethylene‐propylene terpolymerization with fulvenes and various acetylenes. Vinylacetylene, 2‐methyl‐1‐buten‐3‐yne (isopropenyl‐acetylene) or 6,6‐dimethylfulvene in conjunction with ethylene and propylene formed terpolymers which contained conjugated double bonds. The presence of conjugated double bonds was established by infrared and ultraviolet analyses. The terpolymers were randomly unsaturated with sufficient unsaturation to be sulfur‐vulcanized.
Analysis of the volatile combustion products of vinyl plastics
Authors: Boettner E. A. , Ball Gwendolyn , Weiss Benjamin 
Published: April 2003

AbstractThe extensive use of plastics for insulation and building materials has created interest in the possible toxicity of their combustion products. Three poly(vinyl chloride) homopolymers, a vinyl chloride‐vinyl acetate copolymer, and formulations of two of the homopolymers and the copolymer have been examined to determine the composition and toxicity of their combustion products. Differential thermal analysis and thermal gravimetric analysis were used to study the breakdown process which occurred in several steps, the largest and first being the release of hydrogen chloride from the polymer at about 300°C. Approximately 50 products of combustion were then determined qualitatively by using either infrared spectroscopy or a combination of gas chromatography and mass spectroscopy. Quantitative analyses were carried out on 22 of the combustion products, and quantitative changes with varying air supply, temperature, and heating rate were determined. A comparison of the products of the polymers and their formulations is given.
Thermal degradation of polymers. II further thermogravimetric and differential thermal analysis studies of atactic poly(m‐aminostyrene) homopolymers, copolymers, and related polymers
Authors: Still R. H. , Jones P. B. , Mansell A. L. 
Published: April 2003

AbstractThermogravimetric and differential thermal analysis have been employed to study the effect on the thermal degradation pattern in static air of the molecular weight of poly(m‐aminostyrene) homopolymers and copolymers with styrene. Related substituted styrene polymers and copolymers with styrene have also been studied in order to assess the effect of introduction of amino, substituted amino, and hydroxy groupings into a polystyrene main chain. The effect of these groupings on the thermal stability of the polymers as compared with polystyrene suggests that the inherent antioxidant characteristics of the subtituent grouping plays the major role in stabilization. A molecular weight effect has been shown to be operative for m‐aminostyrene, p‐N,N‐dimethylaminostyrene, and m‐hydroxystyrene polymers. This manifests itself in terms of different thermograms rather than by significantly influencing the procedural decomposition temperatures, although a trend is seen.
The determination of the isotacticity of polypropylene in the 90–100% range by infrared spectroscopy
Authors: Hughes Richard H. 
Published: April 2003

AbstractAn infrared method has been developed for the determination of the isotacticity of polypropylene in the 90–100% range. The method requires the annealing of thin films at 165–167°C. for 3 hr. in an inert atmosphere, followed by slow cooling to room temperature. For approximate answers the ratio of the intensity of the 10.00 μ band to that of the 10.27 μ band can be reported as the fraction of isotactic material. Better results are obtained, however, by using Figure 2 as a calibration curve and reading the values from it.
Kinetics of contraction of drawn nylon 66 in aqueous phenol
Authors: Jacobs Martin I. , Rebenfeld Ludwig , Taylor Hugh S. 
Published: April 2003

AbstractThe rate of contraction of drawn nylon 66 in aqueous phenol was investigated, and a method is described for correlating this contraction with a series of elementary rate processes. The rate constants so obtained were analyzed by absolute rate theory, and the variations of ΔH† and ΔS† with phenol concentration gave evidence of the nature of the reaction steps.
Flex life and long‐term strength of composite materials
Authors: Fulmer Glenne E. , Guthrie James L. 
Published: April 2003

AbstractThe relationship is shown between the flex life and long‐termtensile strength of flexible composite material. The long‐term strength is interpreted in terms of a kinetic theory of failure. However, it is not posible to predict the flex life from tensile strength or even long‐term strength data unless the stiffness or modulus is considered along with the thickness of the sample. With these factors it becomes possible to predict the flex life of a material and to compare various flex‐testing instruments utilizing a new concept, which material and to compare various flex‐testing instruments utilizing a new concept, which we call “effective force.” The usefulness of the concept of effective force is explained.
Allylic polymers. Diallyl 2‐substituted succinate prepolymers and their properties
Authors: Nowlin G. , Gannon J. A. , Jungster L. 
Published: April 2003

AbstractDiallyl 2‐substituted succinates, obtainable via the addition of alkenes or alkylaromatics to maleic anhydride, undergo intramolecular cyclization during polymerization to low molecular weight prepolymers. The amount of this cyclization and the properties of the cured prepolymers are profoundly affected by the structure of these 2‐substituents. Thus, the degree of cyclization decreases with these substituents in the order: aralkyl and isobutyl > unhindered alkenyl > alkyl > hindered alkenyl. Properties of thermosetting molding compounds based on these prepolymers are inferior to those of poly‐(diallyl phthalate) molding compounds.
Analysis of condensation polymerization reactors. I. Kinetic model
Authors: Szabo T. T. , Leathrum J. F. 
Published: April 2003

AbstractA mathematical model for the kinetics of polycondensation reactions was developed. Reaction rates were expressed in terms of reactive functional groups where the reactivity of each functional group was assumed to be independent of the size of the polymer molecule. A method of testing the validity of the model with batch reactor data is demonstrated. The model is then employed to derive expressions for the equilibrium constant and molecular weight distributions. Continuous reactor yields and molecular weight distributions are then predicted from the batch reactor data. The reactions considered include chain growth, scission, and ester exchange reactions.
A method of measuring tackiness
Authors: Kambe Hirotaro , Kamagata Kazuo 
Published: April 2003

AbstractFor measuring the tackiness of viscous materials to the solid surface, we designed an attachment to the tensile tester driven with constant speeds. Blends at high molecular weight polyisobutylene with low molecular weight polyisobutylene or with a hydrogenated rosin were used as samples. The maximum force fb at the time tb of the force‐time relation recorded on a chart was determined as a measure of the tackiness. The relation between fb and tb satisfies the equation fb ∝ tb−1/2 derived by Eley. The fb depends on the time tc and the pressure pc at contact, the temperature and the rate of sepration, r, and the rosin content of the sample. The activation energy, obtained from the slope of plots of fb against the reciprocal of the absolute temperature shows a value of 2–6 kcal/mole, which is similar to the activation energy of the viscous flow. To decide whether the failure occurs at the interface or within the adhesive itself, fb was measured with cylinders made of various materials such as polytetrafluoroethylene, polyethylene, poly(methyl methacrylate), and brass.
Radiation‐crosslinked polypropylene: Physical and dielectric properties
Authors: Benderly Asaf A. , Bernstein Bruce S. 
Published: April 2003

AbstractIrradiation of two stereoregular polypropylenes and a polyallomer via 60Co in the presence of 3–8% allyl methacrylate (AMA) monomer, to does up to 5 Mrad, lead to an improvement in mechanical properties. With irradiation, heat resistance, tensile strength, and gel fractions increased, and creep compliance decreased. The decrease in creep compliance was revealed by measurements of irradiated samples at 1850C (at constant load and monomer level), a temperature above the Tm of polypropylene. Dielectric properties (dielectric constant K and dissipation factor tan δ) were virtually unaffected by irradiation of 0.3 to 5.0 Mrad in nitrogen when AMA was absent. In the presence of monomer, small but generally tolerable increases in tan δ resulted if the monomer concentration was not too great. To obtain improvements in mechanical properties while not simultaneously altering the dielectric losses, it was necessary to keep the AMA concentration to a maximum of 4%.
Effects of molecular weight distribution and branching on rheological properties of polyolefin melts
Authors: Combs R. L. , Slonaker D. F. , Coover H. W. 
Published: April 2003

AbstractThe objective of this work was to determine the relationships among molecular and melt parameters of polyolefins. The polyolefins studied are polypropylene, poly‐1‐butene, poly‐1‐hexene, poly‐1‐dodecene, these have regularly spaced short‐chain branches. Conclusions from previous work, as well as some new data, on polyethylene are given. As the molecular weight increases, the critical shear rate decreases but the melt viscosity and non‐Newtonian ratio increase. As the molecular weight distribution broadens, the critical shear rate decreases, whereas the normal forces and the non‐Newtonian ratio increase. Increasing the number of short‐chain branches increases the energy of activation and the melt viscosity but decreases the non‐Newtonian ratio. As the length of the short‐chain branches increases, the non‐Newtonian ratio increases, but the melt viscosity, critical shear rate, and energy of activation decrease. Increasing the number of long‐chain branches decreases the non‐Newtonian ratio, but the normal forces and the melt viscosity increase. Such information allows the polymer chemist to design a polyolefin molecule having the critical melt properties required for a given production technique.
Tensile testing device for measurements on polymeric materials between −100 and +150°C. Mechanical behavior of cellulose in liquid media
Authors: Brunnberg Ingemar , Kubát Josef , Söderlund Gunnar 
Published: April 2003

AbstractA tensile testing device for measurements on polymer samples while immersed in a liquid is described. The temperature range is approximately −100 to +150°C. The sample older containing the immersion liquid is an all‐glass container attached to a modified tensile testing device. The thermostatting and recording equipment is also described. Stress–strain curves obtained with monofilaments of regenerated cellulose immersed in n‐pentane and liquid ammonia are shown. For filaments in n‐pentane the variation of the modulus of elasticity with temperature down to −40°C is also reported as a further example of the applicability of the new device.
Reactions of cotton or diethylaminoethyl cotton with 1‐chloro‐2,3‐epithiopropane
Authors: Ward Truman L. , Benerito Ruth R. , McKelvey John B. 
Published: April 2003

AbstractSulfhydryl groups have been introduced into cotton and into diethylaminoethyl (DEAE)‐cotton by reaction with neat 1‐chloro‐2,3‐epithiopropane or alcoholic solutions of the thiirane. Reactions at room temperature have been compared with those at higher temperatures, and fabric properties obtained with various S/Cl ratios have been compared. The effects of additional external base catalysis on these reactions have been studied. Fabric properties resulting from cotton–1‐chloro‐2,3‐epithiopropane or DEAE‐cotton–1‐chloro‐2,3‐epithiopropane reactions have been compared with properties obtained with the corresponding reactions of cotton or DEAE‐cotton with epichlorohydrin. Sulfhydryl groups have also been introduced into cotton and DEAE‐cotton by the in situ formation of 1‐chloro‐2,3‐epithiopropane in the fabric as a result of the reaction of the oxygen analog with a thiourea or a thiocyanate. These in situ reactions have been carried out in the absence and presence of solvent and external base catalysts. Attempts to vary the wet and conditioned (dry) recovery angles by oxidation of sulfhydryl groups and by reduction of disulfide groups met with little success. Smaller improvement in wrinkle recovery properties imparted by the thiirane than by epichlorohydrin at a given add‐on has been explained on the basis of greater tendency of the thiirane to open abnormally in neutral or slightly acidic conditions and thus the greater tendency of the thiirane to form polymers rather than to crosslink cotton. Tendency of the oxirane to open normally and therefore act difunctionally results in finished fabrics with low chlorine contents, a high degree of crosslinking, and little polymer formation.