bluuebunny/crossref_metadata_2025_split huggingface dataset:
Colligative properties of polyelectrolyte solutions. IV. Activity coefficient of sodium ion
Authors: Nagasawa Mitsuru , Kagawa Ikumi 
Published: April 2003

AbstractBy the concurrent use of the ion exchange membrane electrode in addition to the sodium amalgam electrode, the ionic activity of sodium ion in salt‐free polyelectrolyte solutions was determined over a considerably wide range of sample concentration. As polyelectrolyte samples, several kinds of sodium polyvinyl alcohol sulfates differing in their degrees of esterification and degrees of polymerization (sodium polystyrene sulfonate, sodium cellulose sulfate, and carboxymethylcellulose) were used. The peculiar dependency of the activity coefficient of sodium ion upon the sample concentration first noted by Kern was confirmed with all samples in this study; that is, γNa+ decreases with dilution of the sample solution. Further, it was confirmed that the degree of esterification, viz., the charge density on a linear polymer, is a most important factor while the activity coefficient is entirely independent of the degree of polymerization. The influence of structure of the polymer skeleton upon the activity coefficient was found to be comparatively small. Some of the above results were discussed on the basis of the authors' theory published in a previous paper.
Transitions in plasticized and unplasticized cellulose acetates
Authors: Russell J. , Van Kerpel R. G. 
Published: April 2003

AbstractThe temperature‐dependence of specific volume, rigidity modulus, and mechanical losses of plasticized and unplasticized cellulose acetates in the temperature range −100 to +200°C. has been studied. Two cellulose acetates, a triacetate and a cellulose (2.2) acetate were used, these being plasticized with varying amounts of either benzyl acetate, m‐cresol, o‐ethylphenol, γ‐butyrolactone, monomethylaniline, benzylphenol, or Santophen 7 (a phthallyl glycolate). The specific volume measurements, made using an extremely sensitive dilatometer, indicated three apparent second‐order transitions and one first‐order (melting) transition in cellulose triacetate and three or possibly four apparent second‐order transitions but no first‐order transition in the cellulose (2.2) acetate. Both the first‐order and second‐order transitions were depressed by the addition of plasticizer, the depression being most marked with the phenolic‐type plasticizers. Because of polymer decomposition at temperatures above 200°C., it was not possible to study the melting of mixtures containing less than 30% plasticizer and subsequently no reliable values for the melting temperature, the entropy, and the heat of crystallization could be determined. Rigidity modulus measurements, obtained using a torsional pendulum technique and the mechanical loss (damping) measurements, confirmed the existences of these second‐order transitions in both acetates and indicated that only the highest temperature transition, 175°C. in the triacetate and 195°C. in the secondary acetate, had the characteristics of a normal glass to rubber transition.
Filler reinforcement of silicone rubber
Authors: Bueche A. M. 
Published: April 2003

AbstractModulus and swelling measurements were made on silicone rubber samples compounded with five different fillers. The data were at variance with the predictions of the theory of modulus reinforcement by Weiss, Rehner, Smallwood, and Guth. The results, when analyzed using a modification of the kinetic theory of elasticity proposed by the author, indicate that the increase in modulus and decrease in swelling are due primarily to polymer‐filler attachments. The areas per attachment were found to be of the order of a few square angstroms and to vary with the filler. With some fillers the same area values were obtained from modulus and swelling measurements. With others, the swelling liquid apparently displaces polymer from the filler surfaces.
Infrared spectrum and crystal structure of cellulose
Authors: Tsuboi Masamichi 
Published: April 2003

AbstractInfrared absorption spectra of oriented cellulose fibers have been observed using polarized radiation. Natural fibers are in general too thick but swelling them in NaOH solution followed by pressing, washing, and drying is an effective way of obtaining a suitable thickness in the 650–3100 cm.−1 region. The dichroism observed for the bands which can be assigned has been interpreted on the basis of the crystal structure of cellulose. The CH stretching band is polarized perpendicular to the fiber axis, in accord with the previously proposed model of the crystal structure (Meyer and Misch). Because both the CH2 symmetric and antisymmetric stretching bands are polarized parallel, a modification of the previously proposed model is necessary. In the region of CH and OH deformation frequencies (1200–1500 cm.−1) nine bands are observed, of which four are polarized parallel and five, perpendicular, to the fiber axis. Deuteration effect of amorphous cellulose on the spectrum in this region was examined. Probable assignments are given for these bands. In the region of CO and CC stretching frequencies (800–1200 cm.−1) all the bands are polarized parallel to the fiber axis. Observations were also made on deuterated cellulose, i.e., cellulose which had been swelled in NaOD. Of the six OD stretching bands observed, five show parallel dichroism, indicating that the OH bands in cellulose are arranged predominantly parallel to the fiber axis. The OH out‐of‐plane deformation band at 650 cm.−1 is polarized perpendicular to the fiber axis.
p‐Vinylbenzyltrialkyl ammonium salts in vinyl polymerization
Authors: Jones Giffin D. , Goetz Shirley J. 
Published: April 2003

AbstractPolymers and copolymers of a quaternary monomer, vinylbenzyltrimethylammonium chloride, have been studied. A product similar to that previously obtained by partially chloromethylating polystyrene and aminating with trimethylamine has been made. The product with 15 to 25 mole per cent quaternary groups forms metastable aqueous solutions. Light scattering measurements in the presence of added salt do not indicate aggregation. The quaternary monomer exhibits micellar behavior in conductivity measurements. Copolymers with acrylamide are water‐soluble and substantive to paper pulp; copolymers in minor amount with acrylonitrile are dyeable with acid dyes; copolymers in minor amounts with styrene are clear and free of tendency to pick‐up or maintain a static charge.
Improved rotation viscometer for the study of low viscosity liquids at low and intermediate rates of shear
Authors: Frei E. H. , Treves D. , Eisenberg H. 
Published: April 2003

AbstractAn improved model of a precision rotation viscometer with electrostatic restoring torque for the centipoise range is described. In this instrument torques from 0.1 to 500 dyne cm. are measured with an accuracy of 0.2%. Rates of shear range from 0.1 to 200 sec.−1.
Dependence of mechanical shear degradation of polymers in solution on rate of energy application and on concentration
Authors: Goodman Philip 
Published: April 2003

AbstractThe kinetics of the degradation of polyisobutene in cetane solutions produced by mechanical shearing action in a capillary has been studied as a function of rate of shear energy application and of concentration. The initial rate constant, k, for the degradation was determined as the initial rate of bond cleavage per unit concentration by weight. Log k was found to be a linear function of the reciprocal of the rate of shear energy application per unit volume, J. At all concentrations studied in the range 5–20 weight per cent, log k was the same function of 1/J, but such a plot for 3% solutions had a much greater negative slope. This indicates a decreased efficiency for the concentration of mechanical energy by the polymer molecules in less concentrated solutions.
Polymers and copolymers of N‐1,1‐dihydroperfluoroalkyl acrylamides
Authors: Knobloch Fred W. 
Published: April 2003

AbstractA series of six new fluorinated acrylamide monomers has been studied. These included the N‐1,1‐dihydrotrifluoroethyl acrylamide, the N‐1,1‐dihydroheptafluorobutyl acrylamide and the N‐methyl, ‐ethyl, ‐n‐butyl and ‐isobutyl derivatives of the latter. Homopolymerization of the fluoroacrylamide monomers with benzoyl peroxide readily proceeded both in bulk and solution. Both liquid and crystalline fluorinated acrylamide monomers polymerized in emulsion with persulfate initiators. All homopolymers were thermoplastics which could be cast to yield clear transparent films. Specific evaluation was made of the electrical properties of polymeric N‐n‐butyl‐N‐1,1‐dihydroperfluorobutyl acrylamide before and after exposure to gamma radiation. A time—conversion polymerization curve was determined for the N‐ethyl‐N‐1,1‐dihydroperfluorobutyl acrylamide. The rapid polymerization found for this monomer characterizes the behavior of all the fluorinated acrylamide monomers. Copolymerization proceeded with a number of comonomers which included alkyl acrylates, fluoroalkyl acrylates, vinyl ethers, and several dienes. Reactivity ratios were evaluated for the copolymerization of N‐ethyl‐N‐1,1‐dihydroperfluorobutyl acrylamide (N‐EFBAm) with methyl methacrylate (MMA). Values determined were r1 = 0.89 (N‐EFBAm) and r2 = 0.77 (MMA).The fractionations of two copolymers are discussed in relation to compositional and structural variations present in the copolymers. Indication that these copolymers were essentially linear was provided by a determination of the Huggins empirical slope constants.
Conductivity of solutions of the potassium salts of carboxymethylcellulose and sulfonated polystyrene in the presence of potassium chloride
Authors: Longworth R. , Hermans J. J. 
Published: April 2003

AbstractThe conductivity of the potassium salts of carboxymethylcellulose (CMC) and poly‐p‐styrene sulfonate (PSS) in the presence of KCl shows a behavior which is in striking contrast to the results of a previously developed theory: when the total concentration of K plus Cl ions is kept constant, the conductivity decreases with increasing polymer content in the majority of cases. Qualitatively this can be explained by a theory of the relaxation effect. This theory makes use of the model of a porous sphere in which the counter ions completely compensate the charge of the fixed ions. The use of the Debye‐Hückel approximation is avoided. The charge resulting from relaxation effects is treated as a surface charge.
Propagation of stress waves in rubber rods
Authors: Cramer William S. 
Published: April 2003

AbstractThe propagation of longitudinal, torsional, and flexural waves in rubber rods was studied by a moving probe method. Conditions and materials were used for which the attenuation was sufficient to eliminate standing waves. Velocity and attenuation data were obtained for the different wave types over the frequency range 1 to 8 kc. at or near room temperature for different rubbers of accurately specified compositions. Complex Young's moduli were computed from both the longitudinal and flexural propagation data and found to be in good agreement with each other for the same rods under the same conditions. Complex shear moduli were computed from the torsional data. Ratios of the respective real parts and loss tangents of the Young's and shear moduli showed good agreement with theory but some dependence on material. Measurements were also made of the complex bulk moduli of materials identical to those studied in rod form.
Kinetics of polymerization of nitroethylene. II. Study of molecular weights (by cryoscopic method)
Authors: Vofsi D. , Katchalsky A. 
Published: April 2003

AbstractThe study of the polymerization of nitroethylene in methyl ethyl ketone and catalyzed by bases of the pyridine series—as reported in part I—was extended in the present work. The MW of a number of polymers was determined by a semimicro cryoscopic method, which is described in detail. Of all the reaction parameters, at 20°C., the MW was found to depend only on the initial monomer concentration. To account for this dependence, an additional step was included in the three‐step mechanism suggested earlier, namely, that of catalyst transfer to monomer. Spectroscopic examination of the polymers support the suggestion that termination, or transfer, is accompanied by ring closure and the formation of cyclic structures.
Diffusion in ethylene polymers. II. Desorption of water
Authors: McCall D. W. , Ambrose J. F. , Lanza V. L. 
Published: April 2003

AbstractThe kinetics of desorption for water from various ethylene polymers have been studied by weight loss. In either branched (DYNK) or linear (Marlex 50) polymers the solubility of water was too low to be measured by our techniques (< 0.05 mg. H2O/g. polymer). This result is not in agreement with values reported by earlier workers (0.2–0.9 mg. H2O/g. polymer). When DYNK is oxidized, however, measurable quantities are absorbed. We find 0.11 mg. H2O/g. polymer for DYNK containing about 0.6% oxygen by weight. In this case the desorption data provide a measure of the diffusion coefficient, D ≃ 10−7 cm.2/sec. Similar results are found for a cable compound containing about 5% butyl rubber and 0.07% antioxidant introduced into DYNK by milling.
Molecular motion in polyethylene
Authors: McCall D. W. , Slichter W. P. 
Published: April 2003

AbstractMolecular motion has been studied in a highly branched polyethylene, DYNK, and in a linear polyethylene, Marlex 50. The studies centered around the use of nuclear magnetic resonance spectroscopy, with additional information from measurements of x‐ray diffraction, dielectric relaxation, and the diffusion of small molecules into the polymers. The nuclear resonance studies extended over a temperature range of 80 to 410°K., and studies by the other techniques included some measurements at low and high temperatures. It is shown that crystallinity in the linear polyethylene persists to within only a few degrees of the “melting point” of the gross polymer, and that chain rotation within the crystallites is comparatively restricted until shortly below the temperature of fusion. On the other hand, chain rotation within the crystallites of the branched polyethylene is much freer, presumably due to the presence of lattice defects, such as might be caused by the incorporation of branch points into the crystallites. Crystallinity in the branched polyethylene disappears at much lower temperatures than in the linear polymer. There is considerable motion of chain segments within the amorphous regions of both kinds of polyethylene, although at a given temperature the linear polymer exhibits more constraint than does the branched polymer. It is evident that the amorphous portions of both polymers possess the attributes of a viscous liquid, even at temperatures well below the melting point of the gross material. Activation energies and frequency factors for the motions of chain segments in the amorphous portions have been computed and are compared with the data from earlier measurements of dielectric and mechanical relaxation.
A photoelectric instrument for the measurement of molecular orientation in films of high polymers
Authors: Winogradoff N. N. , Bisset D. C. 
Published: April 2003

AbstractA simple, continuously recording instrument capable of measuring retardations down to the order of 10−8 cm. is described. The instrument is based on photoelectric measurement of the intensity of light transmitted by two crossed rotating Polaroids when an oriented film of high polymer exhibiting optical anisotropy is placed between them. This intensity is related to the birefringences of the sample for light vibrating in three mutually perpendicular directions. These three birefringences can be used to specify physical properties and have been used to study the effect of sorption, desorption, annealing, and stretching processes on molecular configuration. Some examples of such applications are discussed.
Effect of gamma‐radiation on cellulose
Authors: Glegg R. E. , Kertesz Z. I. 
Published: April 2003

AbstractCotton and wood cellulose were irradiated with gamma rays within the dosage range 60 X 103 r to 2,300 X 103 r. A measure of the degradation was obtained from intrinsic viscosities obtained from viscosity determinations in cupriethylenediamine solution. The presence of water had no significant effect on the extent of radiation‐induced degradation. Thus there was little or no difference between the results on irradiated samples of wood cellulose containing 3.3, 4.6, and 5.6% moisture. Cotton cellulose irradiated in the presence of excess water or 3.5% moisture was equally degraded. At lower moisture levels (0.26–0.32%) an aftereffect was observed in which the solution viscosities of the irradiated samples progressively decreased up to 30 days in storage. The duration of the effect was independent of the dosage levels studied. From the experimental results reported here and from recalculations of data in the literature the radiation threshold dosage for isolated celluloses appears to be in the range of 28.4 to 81.2 X 103 r. Cellulose is degraded at gamma‐radiation dosages equal to or below those required for softening plant tissues such as apples, carrots, and beets. Therefore it seems probable that the degradation of this cell wall constituent is a major factor in the radiation‐induced softening of plant tissues.
Effect of olefin structure on the ceiling temperature for olefin polysulfone formation
Authors: Cook R. E. , Dainton F. S. , Ivin K. J. 
Published: April 2003

AbstractCeiling temperatures Tc (at which the free energy change for the reaction is zero) have been determined for the formation of polysulfones from a wide variety of olefins and allyl compounds under standard concentration conditions ([M] [S] = 27 mole2 liter−2, M = unsaturated compound, S = sulfur dioxide). In the 1‐olefin series Tc falls from ethylene to propylene 90°, to 1‐butene 64°, and then remains approximate constant as the chain is lengthened. With 2‐olefins there is a progressive decrease from butene 34°, to pentene 8°, to heptene −38°. Branching invariably lowers Tc and the effect is greatest when the branching is at the double bond; thus isobutene 4°, 3‐methyl‐1‐butene 36°, 4,4‐dimethyl‐1‐pentene 14°. 2‐ethyl substitution of a 1‐olefin, or 2, 3, or 4 branching of a 2‐olefin results in inability to react (Tc < −80°). Cycloolefins have Tc values considerably higher than the corresponding 2‐olefins; thus cyclopentene 102°, cyclohexene 24°. In the allyl compounds a carboxyl group tends to lower Tc but a hydroxyl group raises Tc. An ether group raises Tc slightly. The results are discussed in terms of structural effects on the heat and entropy changes and on the monomer activity coefficients and polymer solubilities. The infrared absorption spectra of 20 polysulfones and 3 aliphatic sulfones are recorded for the sulfone stretching region (7.5–9.5 μ).
Dynamic viscosity and shear modulus of molten polystyrene as a function of molecular weight
Authors: Cox W. P. , Nielsen L. E. , Keeney R. 
Published: April 2003

AbstractThe dynamic mechanical properties of several polystyrene fractions were measured in the frequency range 0.05–5 cycles per second and the temperature range 160–220°C. Data obtained at different temperatures with each fraction were superposed by means of Ferry's reduced variables. The empirical temperature shift factors involved in this superposition agreed well with values calculated from the universal function of Williams. The observed molecular weight dependence of the dynamic properties agreed qualitatively with the predictions of the Rouse theory as modified by Ferry, Landel, and Williams for application to polymer melts.
Theory of light scattering by polymer solutions
Authors: Flory P. J. , Bueche A. M. 
Published: April 2003

AbstractThe intermolecular contribution to light scattering by polymer solutions has been treated according to the smoothed Gaussian sphere model. Combining the results with the usual term for the individual molecule scattering we obtain for the reciprocal turbidity:

The third virial term is also formulated. The angle dependent factor Q(θ) falls appreciably below unity at higher angles for large molecules in good solvents. Calculation of Q(θ) according to the theory is illustrated. Its replacement by unity may under some circumstances invite appreciable error.
Infrared spectra of high polymers. VI. Polystyrene
Authors: Liang C. Y. , Krimm S. 
Published: April 2003

AbstractThe infrared spectrum of polystyrene has been obtained in the region of 70 cm.−1 to 3200 cm.−1. These data, plus Raman scattering data from the literature, are used to make a complete assignment of the normal modes of the polystyrene molecule. The benzene ring modes have been analyzed in detail in terms of C2v symmetry, and a set of normal vibrations has been proposed. On the basis of previous analyses of the benzene and monosubstituted benzenes, and a study of the combination bands, it has been possible to make a fairly satisfactory assignment of all of the benzene ring fundamentals. Assignments of the CH2, CH, and skeletal modes are made on the basis of previous studies of spectra of high polymers. The interpretation of the spectrum is in agreement with other evidence that the chain configuration is a random one, i.e., that the polymer is amorphous.
Reactions of phosphoric acid with polyvinyl acetals
Authors: Barnes Roderick A. 
Published: April 2003

AbstractTwo of the possible reactions between polyvinylbutyral and phosphoric acid in 95% ethanol have been investigated. Some hydrolysis of the acetal linkages has been found to take place although the extent of this reaction is less than for simple monomeric acetals. No evidence has been found to indicate that there is, in ethanol, any esterification of the phosphoric acid by the hydroxyl groups of the polymer.
A light scattering study of alfin polybutadiene
Authors: Cleland Robert L. 
Published: April 2003

AbstractThe weight average molecular weights, Mu, of some unfractionated Alfin polybutadienes ranged from 5 to 20 million. The ratio of the mean‐square radius of a linear polybutadiene molecule to its molecular weight in a thermodynamically neutral solvent is estimated to be R2/M = 2.2 (±0.3) × 10−17 cm.2g.−1 mole. The relationship [η] = 0.125 Mv0.77 between intrinsic viscosity and molecular weight is estimated for linear polybutadiene in cyclohexane at 25°. The average value of Φ′, the parameter in the Flory‐Fox theory of intrinsic viscosity, is found to be 3.6 × 1024 mole−1 (or Φ = 2.5 × 1023 mole−1) for linear molecules and appears to increase with branching. Branching is found to decrease with increasing conversion for this polymer. Values of the osmotic second virial coefficient, A2, are discussed in connection with theoretical predictions. Various corrections to measured quantities required because of polydispersity in polymer samples are presented.