bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wool–polymer systems: Effect of vinyl polymers on water absorption
Authors: Leeder J. D. , Pratt A. J. , Watt I. C. 
Published: April 2003

AbstractAcrylamide, acrylic acid, and acrylonitrile have been polymerized in situ within wool fibers and the water‐absorption properties of the resultant wool–polymer systems compared with those of wool and the polymers measured separately. At high humidities, polyacrylamide and, to a lesser extent, poly(acrylic acid) caused increased water uptakes when expressed as a function of the original weight of wool, due to the hydrophilic nature of these polymers. This increase was less than that expected from the water contents of the wool and polymers measured as separate entities. Chain entanglements in the polymer–keratin network may be responsible for some reduction of water content. The presence of polyacrylonitrile in wool reduced the water content at high humidities to less than that of wool alone, indicating that “volume exclusion” of water by the polymers is also a contributing factor. At low humidities, the water content of the wool–polyacrylamide system is equivalent to the sum of the water contents of wool and polymer taken separately; in the case of poly(acrylic acid) the water content is less than that of wool and polymer considered separately, and this is attributed to ionic bonding. For wool containing polyacrylonitrile there is a reduction in water content at low humidities, indicating interaction between the polymer and polar sorption sites in the wool.
Relation between impact strength and dynamic mechanical properties of plastics
Authors: Wada Yasaku , Kasahara Tetsuo 
Published: April 2003

AbstractA simple theory is developed which correlates the Izod impact strength of polymers with (G′100‐G′300)2/G′100, where G′100 and G′300 are dynamic shear moduli at 100°K. and 300°K., respectively. The theory assumes the Maxwell element for the material and the fracture time smaller than the relaxation time. The theory is verified by experimental data for numerous polymers. Another approach which correlates the impact strength with the integrated loss factor from 0 to 300°K. is also proved valid.
Oil well sand consolidation. I. Resins for a three‐step process
Authors: Parker P. Harold , Treadway B. R. , Brandt H. 
Published: April 2003

AbstractOil‐bearing formations often consist of loose sandy material. In the production of oil from these formations sand tends to be carried to the well bore along with the oil. The flow of sand can be prevented by consolidating or cementing together the sand particles of the formation around the well bore. The cementing has to be accomplished in such a manner that fluid flow channels between particles remain open. This paper describes a new three‐step process that was developed to consolidate oil well sand. The steps in the process involve injection of: (1) resin, (2) inert fluid, and (3) inert fluid containing a catalyst. In the first step of the process, resin in injected into the formation where it fully saturates the interstices between sand grains. Permeability is established in the second step by displacement of the excess resin from the interstices, thereby leaving a thin film of resin on the sand grains. In the third step, polymerization is activated by migration of catalyst from the inert fluid into the thin resin film on the sand. The process has the advantage that resin is placed and permeability is established before the resin is catalyzed. This avoids premature polymerization of the resin which might cause plugging of the formation or the tubing string used to inject resin. Desirable characteristics of a resin for the three‐step process are: (1) viscosity of 25–200 cp. at well bore temperature; (2) stability for several days at well bore temperature; (3) high adhesion to sand in the presence of an inert flushing fluid; (4) polymerization by less than 10% catalyst; (5) the polymerized resin binds sand together with a strong bond that is not affected by well fluids. Five different resin types have been tested for use in the three‐step sand consolidation process. These are: (1) epoxy–anhydride cured with a tertiary amine; (2) epoxy–epoxy diluent cured with a primary–tertiary amine mixture; (3) furan; (4) unsaturated polyester–vinylpyrrolidone; (5) unsaturated polyester–styrene. The two epoxy resins give strong, permeable consolidated sand which is resistant to well fluids such as brine and crude oil. The furan resin gives a weak consolidation. The unsaturated polyester–vinylpyrrolidone gives good strength and oil resistance but is sensitive to brine. The unsaturated polyester–styrene is difficult to apply. Many oil wells have been successfully treated in the Gulf Coast area and in California with the two epoxy resins. Almost all of these wells are producing free of sand, and, to date, more than five million barrels of oil have been produced from these wells.
Cellulose propionylpropionate as a side product in the reaction of cotton cellulose with propionyl chloride
Authors: Sircar Anil K. , Stanonis David J. , Conrad Carl M. 
Published: April 2003

AbstractIn the reaction of cotton cellulose fiber with propionyl chloride in pyridine–DMF medium, the degree of substitution based on weight gain was much higher than that based on saponification. Gas–liquid chromatograms of the pyrolysis products of the samples showed an extra peak. This was identified as 3‐pentanone, which arises from the pyrolysis of α‐propionylpropionic acid, a substance which was proposed by Malm and co‐workers as a possible side product. This conclusion was further confirmed by the infrared and NMR spectra of the liquid, collected fractionally on pyrolysis of the sample. Quantitative GLC showed that one òut of every four hydroxyl groups is substituted with an α‐propionylpropionyl moiety, the rest with propionyl groups. A possible mechanism for the side reaction has been proposed.
Epichlorohydrin–triethanolamine reaction in the preparation of quaternary cellulose anion exchangers
Authors: McKelvey John B. , Benerito Ruth R. 
Published: April 2003

AbstractThe reactions between cotton cellulose and a mixture of triethanolamine and epichlorohydrin in the presence of aqueous NaOH have been studied. It has been shown that cotton fabric pretreated with aqueous base and then reacted with a 3:1 mole ratio of epichlorohydrin to triethanolamine forms a strong base anion exchanger. Resultant properties differed from those of the product made by the conventional method of preparing ECTEOLA cellulose, a commercial product of the same reactants. Titration curves of the strong base cellulose exchangers were similar to that obtained with the product of the reaction between cotton and trimethylglycidylammonium chloride. Substitution of triethylamine for the triethanolamine also resulted in a quaternary base cellulose anion exchanger. A cyclic diquaternary salt, [2,5‐p‐dioxanylenebismethylene] bis[tris(2‐hydroxyethyl)ammonium chloride], has been isolated from the triethanolamine–epichlorohydrin mixture and a mechanism of the reaction has been proposed.
Reversible gelation of acrylonitrile–vinyl acetate copolymer solutions. II. Mechanical properties
Authors: Paul D. R. 
Published: April 2003

AbstractConcentrated solutions of acrylonitrile polymers exhibit reversible gelation. The rate of gelation at 25°C. was determined for various solutions of an acrylonitrile copolymer containing 7.7% vinyl acetate in mixtures of dimethylacetamide (solvent) and water (nonsolvent) by measuring the shear modulus of the forming gel as a function of time. The mechanical properties were also measured on a series of gels formed by cooling solutions to −78°C. It was found that both the rate of gelation at 25°C. and the modulus of gels formed at −78°C. increase very rapidly as either the solids level of the solution of the water content of the solvent is increased. The gelation rate data wree correlated with the gel melting points of the gels. The results are discussed and compared with the analogous but limited data available for other systems.
Statistical description of the uniaxial creep behavior of polypropylene foam
Authors: Lepper Jay K. , Hetherington Norriss W. 
Published: April 2003

AbstractThe basis of a statistical method for the analysis of creep data is described. The method consists of response surface fitting to a Taylor series expansion of a function about a point. The method is capable of treating multiaxial stress data and includes other variables, such as temperature, without undue mathematical complications. In addition, the statistical approach can account for such things as experimental error and sample variation. The uniaxial compressive creep‐recovery behavior of a newly developed polypropylene foam was measured under loads of 140–705 g./cm.2and temperatures of 23–74°C. The foam has a nominal density of 0.07 g./cc. and a mean molecular weight between crosslinks of 10,000. The creep behavior is described by a Taylor series expansion through the second order of a function of applied load, test temperature, foam density, and log time.
Preparation and properties of polymers of secondary alkyl crotonates and related monomers
Authors: Graham Roger K. , Moore James E. , Powell John A. 
Published: April 2003

AbstractThe anionic polymerization of a variety of secondary alkyl crotonates and related monomers initiated by fluorenyllithium (complexed with tetrahydrofuran) in toluene at −78°C. is reported. No crystallinity could be developed in any of the samples, and nuclear magnetic resonance was uniformative about possible tacticity. The polymerization techniques were ineffective when applied to n‐alkyl esters. Polymer was obtained from isopropyl cinnamate and N,N‐dimethyl crotonamide, but not from isopropyl thiocrotonate or isopropyl 2‐pentenoate. The physical properties of injectionmolded specimens of polymers of isopropyl, s‐butyl and cyclohexyl crotonate were examined in some detail; the polymers exhibited a desirable combination of high service temperatures and good impact resistance for a vinyl homopolymer but were extremely difficult to mold. Poly(isopropyl crotonate) had a heat distortion temperature of 125°C. at 85 psi, a notched Izod impact of 2.4 ft.‐lb./in. of notch, and a flexural modulus of 274,000 psi.
Phenol transport in cellulose acetate membranes
Authors: Lonsdale H. K. , Merten U. , Tagami M. 
Published: April 2003

AbstractPast detailed studies of solute transport through reverse‐osmosis membranes have been conducted only with simple salts. The present work with phenol was undertaken largely because of the practical observation that the transport of low molecular weight organics is much more rapid than that of the salts. Studies of phenol sorption from dilute aqueous solution indicate that the diffusion coefficient for phenol in water‐saturated 39.8 wt.‐% acetyl cellulose acetate is 9.6 × 10‐10 cm.2/sec., and the equilibrium distribution coefficient between the acetate phase and water is 42. Thus, the diffusion coefficient is quite close to that measured for sodium chloride, and the higher permeability of the membranes to phenol can be attributed entirely to their greater sorption of this solute. In direct osmosis experiments performed with significant water flow a measurable interaction or positive coupling between water and phenol flows has been observed. Further evidence of flow coupling is derived from reverse osmosis experiments in which significant negative solute rejection is observed; i.e., the permeate is enriched in phenol by as much as 20%. It is shown that a solution‐diffusion transport model is not adequate to rationalize the results, and a more complex transport model is apparently required.
Dynamic behavior of natural rubber during large extensions
Authors: Harwood J. A. C. , Schallamach A. 
Published: April 2003

AbstractThe stresses and energy losses during simple extension cycles up to a maximum elongation of 530% have been determined for an unfilled vulcanizate of natural rubber as a function of the temperature and extension rate. At sufficiently short elongation times and low temperatures, the rate and temperature dependence of the ascending stresses are connected by the Ferry transform, and the superposition principle can be applied to them. Outside this experimental range, the stresses are increased by crystallization. The validity of the Ferry transform for the energy losses and the energy loss ratio is more restricted than for the stresses, and the losses are always higher than can be expected from a purely viscoelastic mechanism. The additional losses are tentatively ascribed to incipient crystallization and stress‐softening effects. At short elongation times and low temperatures, the losses approach the values predicted by viscoelasticity, and the loss ratio becomes independent of the maximum extension of the strain cycle.
Delayed yielding of epoxy resin. II. Behavior under constant stress
Authors: Ishai Ori 
Published: April 2003

AbstractCreep tests were carried out on epoxy resin specimens at room temperature and at different high stress levels under tension, compression, and flexure. Compared with the behavior at constant strain rate (CSR) reported in Part I of this work, creep strain–time curves revealed a distinct delayed yielding region of constant minimum rate (secondary creep) followed by a post‐yielding region of increasing slope (tertiary creep). In all cases, results indicate linearity between creep stress and log secondary creep rate, which is almost coincident with the corresponding relationship between yield stress and strain rate obtained in subsequent CSR loading cycles with the same specimens. The similarity in behavior under both the creep and CSR modes conforms to Eyring's theory of non‐Newtonian viscous flow at high stress levels and low temperature. Theoretical analysis yields reasonable values of the activation volume, which is unaffected by the loading and test modes or by loading history, and could thus be regarded as an intrinsic parameter of the microstructure, inherently related to the viscoplastic process involved. The above considerations indicate a deviatoric stress‐biased diffusional mechanism as the predominant factor in the yielding of an amorphous glassy epoxy system.
Regulation of molecular weight of styrene—butadiene rubber. I. Choice of regulator from the homologous series of xanthogen disulfides
Authors: Václavek Vladimír 
Published: April 2003

AbstractThe regulating efficiency of 14 dialkyl xanthogen disulfides in emulsion copolymerization of butadiene with styrene at +5°C. with the use of a diisopropylbenzene hydroperoxide–complexed ferrous iron–sodium formaldehyde sulfoxylate redox system in the presence of sodium soap of disproportionated rosin as an emulsifier, was evaluated. The apparent chain transfer constants of n‐alkyl and isoalkyl derivatives decreased logarithmically with increasing length of the alkyl group, which seems to be related to the analogous dependency of their solubilities in water. The dialkyl xanthogen disulfides, especially the lower homologs, acted as retarders of polymerization. The retardation did not affect their regulation efficiency. On the basis of values of the apparent chain transfer constants it is possible to predict the molecular weight of polymers, except for the region where the regulation is poor and where the deteriorative influence of termination and crosslinking reactions takes place. The diisopropyl xanthogen disulfide has been selected as the most convenient of the compounds studied for molecular weight regulation of emulsion copolymerization of butadiene with styrene in the system mentioned.
Transparency measurement of plastic sheet and film
Authors: Binsbergen F. L. , Van Duijn J. 
Published: April 2003

AbstractAvailable methods for testing the transparency of plastic sheet and film have been found inadequate as regards the correlation between measurement and visual observation. A newly developed procedure, based on the determination of light transmission within a very small angle, gives good correlation. The application of the method and its limitations, due to the difference in optical effect of small‐angle and large‐angle scattering, are discussed. A description is given of the instrument, a special feature of which is that it gives direct readings of optical density and transparency.
Dilute solution properties of hydroxyethyl starch
Authors: Cerny L. C. , Graham R. C. , James H. 
Published: April 2003

AbstractThe dilute solution properties of hydroxyethyl starch (HES) were examined by using the techniques of osmometry, light scattering, and viscometry. The molecular weight range was approximately 2 × 106–0.06 × 106. Since HES is a branched molecule, its properties were compared with those of two linear counterparts, ethyl hydroxyethyl cellulose and hydroxyethyl cellulose. The branching index g was estimated to be about 0.3 when calculated from the intrinsic viscosity, radii of gyration, and second virial coefficients.
Supramolecular structure of propionylated cotton cellulose
Authors: Sircar A. K. , King Walter D. , Conrad Carl M. 
Published: April 2003

AbstractHeterogeneous propionylation of cotton cellulose, in the form of yarn, was carried out by reaction with propionyl chloride, in a medium of pyridine and dimethylformamide (DMF). The product was a mixed propionate–α‐propionylpropionate ester of DS varying from 0.24 to 2.94. The supramolecular structure of these esters was studied by kinetic analysis as well as by the measurements of density, refractive index, and x‐ray diffraction. The Sakurada plot of DS against time of reaction showed a discontinuity at a DS of about 2.0, where the x‐ray diffraction pattern shows almost complete loss of crystalline structure. The interpretation, based on the assumption that the Sakurada curve actually represents the sum of two simultaneous rate processes acting in the amorphous phase and at the crystalline surfaces, seems to explain the data adequately. The density showed a continuous decrease, consistent with the idea of continuous destruction of crystalline structure with progressive substitution. Refractive indices showed a continuous decrease with substitution and birefringence was almost absent at complete substitution. The calculated value of molar refraction for the sample of DS 2.94 agreed closely with the experimentally observed value. The x‐ray diffraction intensity traces gave convincing evidence of the progressive decrystallization of cellulose with the degree of substitution. Decrystallization seems to be more or less complete at about a DS of 2.0.
Nitric acid digestion and crystallinity of ethylene–vinyl acetate copolymers
Authors: Barlow A. , Campbell R. C. 
Published: April 2003

AbstractNitric acid digestion studies of ethylene–vinyl acetate copolymers indicated that copolymers containing identical amounts of vinyl acetate but varying in melt index differed in crystallinity. These results were confirmed by x‐ray analysis. The differences in crystallinity were interpreted as showing a variation in the degree of short‐chain branching in the polyethylene segments of the copolymer chain. This variation was correlated with the conditions of synthesis.
The desorption of ethane–butane mixtures from polyethylene
Authors: Robeson Lloyd M. , Smith Theodore G. 
Published: April 2003

AbstractThe desorption of mixtures of ethane and butane at atmospheric pressure from low‐density polyethylene was investigated over the temperature range from 20 to 60°C. Desorbed penetrants were continuously trapped in glass tubes immersed in liquid nitrogen, and composition was determined as a function of time by means of gas chromatography. The ratio of the quantity of desorbed gas at any time t, qt, to the quantity at complete desorption, q∞, was used to determine diffusion coefficients and solubility constants. The diffusion coefficients for both ethane and butane increase with increasing butane concentration in the temperature interval investigated. The solubility of both penetrants can be correlated by Henry's law at 40, 50, and 60°C. However, at 20 and 30°C. the solubility constant for both penetrants increases with increasing butane concentration. This trend is consistent with experimental observations for single‐component diffusion and solubility of several hydrocarbons in polyethylene, where increasing concentration of penetrant plasticizes the polymer, resulting in increasing diffusion coefficients and solubility constants.
Bis[4(1‐methyl‐1,2‐epoxyethyl)] derivatives of phenyl ether, 1,4‐diphenoxybenzene, and bis(4‐phenoxyphenyl) ether
Authors: Neville Roy G. , Mahoney John W. 
Published: April 2003

AbstractThe syntheses of three new α‐methyl‐substituted bis(epoxyethyl) derivatives of phenyl ether, 1,4‐diphenoxybenzene, and bis(4‐phenoxyphenyl) ether are reported. Improved procedures for preparing 1,4‐diphenoxybenzene and bis(4‐phenoxyphenyl) ether by the Ullmann method are described. Infrared spectral data for the bisepoxides and their precursors are given, as are some reactions of the bisepoxides.
Permeation of water and sodium chloride through cellulose acetate
Authors: Rosenbaum Shlomo , Mahon H. I. , Cotton O. 
Published: April 2003

AbstractThe factors contributing to the selective permeation of water and sodium chloride through cellulose acetate membranes have been examined by the use of radioactive tracers. With decreasing acetyl content both the partition coefficient (solubility) and diffusion coefficient of water increased, the latter the more sharply. The effect was even more pronounced for salt, indicating that increasing selectivity with acetyl content stems mainly from increasingly preferential restrictions on salt mobility. Trends identical with those mentioned for decreasing acetyl content were found for increasing amounts of cellulose acetate solvents that had been extracted with water to yield more highly swollen membranes. A free‐volume treatment for diffusion of small molecules below the glass transition temperature with the aid of subgroup motion in the polymer is used for both components. The water content of the membrane at (or near) saturation emerged as the predominant factor in the permeation behavior. In view of the similarity in the activation energies of water and salt diffusion the far steeper dependence of the salt diffusion coefficient on water content could not be accounted for by size differences between the diffusing species and has been attributed to confinement of salt ions to locations at which multiple water contacts are feasible.
Infrared–deuteration study of regenerated cellulose fibers
Authors: Cumberbirch R. J. E. , Jeffries R. 
Published: April 2003

AbstractThis paper describes a study by infrared, deuteration, and other techniques of the fine structure of three regenerated cellulose fibers (Fortisan, a super tire yarn, and a fiber of high wet modulus). The infrared and deuteration measurement provide information on the amount and perfection of the hydrogen‐bond ordered material in these celluloses. The three fibers are markedly different in structure: the Fortisan contains about 40% ordered cellulose of a high average degree of perfection, whereas the super tire yarn contains a smaller amount (about 20%) of ordered cellulose of a lower average degree of perfection: the yarn of high wet modulus contains about as much ordered material as the Fortisan, but of an average degree of perfection more similar to that of the super tire yarn. Infrared‐dichroism measurements on the fibers are described. The infrared and dichroism studies are discussed in relation to the results of x‐ray, moisture regain, acid hydrolysis, and birefringence measurements on the fibers. The infrared‐deuteration behavior of acid hydrolysis residues prepared from the three fibers is described; these residues are more highly ordered than the patent fibers, but yield no information of any value in characterizing the structures of the parent fibers.