bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sorption of water by wool
Authors: Windle J. J. 
Published: April 2003

AbstractA model for the system of wool plus sorbed water is proposed in which the sorbed water consists of three distinct molecular species: localized water irrotationally bound to localized sites in the fiber, mobile water with properties identical to bulk water, and intermediate water with a potential energy of sorption between that of the localized and mobile water. The theoretical isotherm for this system has been determined from statistical considerations and compared with the experimental isotherm for wool reduced to one hydrostatic pressure. The statistical parameters of the model have been evaluated thereby and the distribution of the sorbed water among the three energy states inferred. The nature of the localized sites and the properties of the sorbed water are discussed. The model is applied to the interpretation of data on the microwave dielectric behavior of wool–water systems, the heat of wetting of wool, and the effects of sorbed water upon the elastic properties of the fiber.
Oxidative degradation of polyethylene
Authors: Beachell Harold C. , Nemphos Spero P. 
Published: April 2003

AbstractThe degradation of polyethylene in molecular oxygen between 150 and 250°C., in ozone‐enriched O2 between 20 and 109°C. and in fuming HNO3 between 25 and 83°C. has been studied. The solid, liquid, and vapor products have been analyzed by means of their infrared spectra. Kinetically, the O2 oxidation reaction appears to be second order. The Elovich chemisorption equation dq/dt = ae−αq was applied to the data and yielded comparable results. The kinetics were followed by pressure change and constant pressure measurements of oxygen uptake, and by the rate of increase of bands in the infrared spectra. The activation energy of the process was found to be 8–9 kcal./mole for the volumetric and manometric studies as well as for the ozone‐catalyzed reaction, while the HNO3 oxidation gave a 35.6 kcal. value.
Rupture of rubber. IV. Tear properties of vulcanizates containing carbon black
Authors: Greensmith H. W. 
Published: April 2003

AbstractThe tear properties of natural rubber and GR‐S vulcanizates containing carbon black are compared with those of gum vulcanizates, using a method developed in a previous paper. The distinctive features in the tear behavior of the filed vulcanizates are noted and discussed. The results indicate that there are two types of tear process, which vary in importance according to the tearing conditions, and the influences of carbon black on these processes is discussed.
Viscosity measurements on molten polyethylene
Authors: Philippoff W. , Gaskins F. H. 
Published: April 2003

AbstractThe flow curves for two samples of molten polyethylene and one of plasticized polyvinylbutyral were measured in a large range of rates of shear and shearing stresses. Two conicylindrical viscometers of greatly different dimensions were used to obtain the wide ranges; the data from these viscometers coincided in the region of overlapping. The behavior of the molten plastics is essentially parallel to the one for solutions of high polymers. Absolute values of the initial viscosity of these polyethylenes at different temperatures were close to those obtained by Dexter on other polyethylenes. The apparent activation energy for viscous flow calculated from these experiments was very similar to the ones reported in the literature.
Studies on carbon black. III. Theory of bound rubber
Authors: Villars D. S. 
Published: April 2003

AbstractOn the hypothesis that “bound rubber” is a gel of carbon black particles, the bonding agent of which consists of the longer polymer molecules, a statistical theory is developed. The probability is first computed that a rubber molecule of i segments will be attached to j carbon black particles. By means of this probability the number and weight of molecules connecting carbon black particles are calculated. The theory predicts loadings below which bound rubber may not be expected (carbon black runs through into extract), and relates amount of bound rubber to total surface area of the black and the molecular weight of the remaining dissolved rubber to that of the rubber originally present. The theory gives a logical explanation of the often observed preferential adsorption by carbon black of polymer molecules of higher molecular weights.
Infrared spectra of the crystalline modifications of cellulose
Authors: Marrinan H. J. , Mann J. 
Published: April 2003

AbstractThe bands due to stretching of OH groups of all four crystalline modifications of cellulose have been measured using a deuteration technique which enables crystalline regions to be studied independently of amorphous regions. Cellulose III prepared from cellulose I (IIII) was found to be different from cellulose III prepared from cellulose II (IIIII). Similarly different cellulose IV's were obtained from celluloses I and II (IVI and IVII). However, the infrared spectra suggest that only one of these, namely, IIII should be regarded as having a crystal structure distinctively different from those of cellulose I and II. Thus IVI and IIIII closely resemble celluloses I and II, respectively, while IVII shows a diffuse absorption and may well possess a disordered lattice. The bearing of these results on the crystal structures of celluloses I and II is discussed.The unit cells of celluloses IIIII and II are different, although their infrared spectra are very similar. These facts suggest that hydrogen bonding in these two forms is of the layer type in the (101) plane, though the possibility of hydrogen bonding in the (101) plane cannot be entirely eliminated.
Tensile stress in jets of viscoelastic fluids. II
Authors: Gavis Jerome , Gill Stanley Jensen 
Published: April 2003

AbstractA viscoelastic fluid jet is treated as a moving infinite string under slowly varying tension. When the system is subjected to a sinusoidal point vibration, the resulting wave form enables the tension to be determined along the jet. The total tension is composed of a surface reaction and an internal, decaying tension. The surface reaction may be calculated from the surface tension of the jet fluid and the radius of the jet. Data for 1.4 and 1.7% carboxymethylcellulose water solutions are presented for three different jet radii and for solution temperatures of 5, 25, and 35°C. It is found that the observed tensions approach the calculated surface reaction far from the nozzle. The rate of decay is a function of concentration and temperature. The internal tension for a 1.7% solution at 25°C. was observed to decay from about 8000 to 500 dynes/cm.2 in 200 milliseconds. Relaxation times of 0.27 sec. for 1.4% and 0.32 sec. for 1.7% solutions at 25°C. describe the internal tensile properties between 40 and 200 milliseconds after ejection.
Hydrodynamic properties of polyelectrolytes. Part III. Sodium alginate
Authors: Mathieson A. R. , Porter M. R. 
Published: April 2003

AbstractThe viscosity and streaming birefringence of fractionated and unfractionated samples of sodium alginate have been measured at various concentrations, and rates of shear, and in the presence and absence of added salt. The viscosity data show the concave upward curve typical of polyelectrolytes at low concentrations, but pass through a minimum at higher concentrations. The influence of shear is least at this minimum. The initial slope of the orientation angle versus velocity gradient curves increases with concentration, but Δn/c is independent of concentration. The semiempirical theory of Peterlin for concentrated solutions is obeyed by the data for Δn, but not by that for the orientation angle. Molecular weights have been calculated from the hydrodynamic parameters. The viscosity behavior is interpreted in terms of the rigidity of the molecule.
Degradation of long‐chain molecules by ultrasonic waves. Part VI. Effect of pressure
Authors: Brett H. W. W. , Jellinek H. H. G. 
Published: April 2003

AbstractUltrasonic degradation of polystyrene in benzene solutions has been studied as a function of pressure exerted on the solutions. Appreciable differences in the rate and extent of degradation have been found if the pressure was exerted via a mercury column, the solutions being saturated with gas at one atmosphere or if the pressure of nitrogen over the solutions was increased, the solution being saturated with nitrogen at each respective pressure.
Oxidation of polybutadiene. I. Rate of oxidation
Authors: Bauman Richard G. , Maron Samuel H. 
Published: April 2003

AbstractThe rate of oxidation of thin films of polybutadiene have been studied between 50 and 90°C. The films were prepared directly from latex by dipping, and thoroughly purified. The oxidation rates were found to go through an induction period, to accelerate rapidly to a maximum, and then to decrease to low values. The decrease in rate past the maximum may be due to consumption of polymer, or diffusion control of the rate. Test of the latter possibility showed the oxidation process to be diffusion limited at 90°, but not at 50°C. These results show that change of temperature leads here actually to a change in the mechanism of the oxidation process.
The structure of polysiloxanes: Solvent swelling of soluble polymethylsiloxanes
Authors: Price Fraser P. , Martin Sylvia G. , Bianchi Joseph P. 
Published: April 2003

AbstractViscosity–molecular weight relationships for polymethylsiloxanes of Me/Si from 2.0 to 1.5 have been determined in a variety of solvents. It has been found that, at Mw = 106, in going from an ideal solvent to the best solvent used, 2.0, 1.8, and 1.5 Me/Si polymers expand volumetrically by factors of 3.8, 2.0, and 1.15, respectively. This is consistent with the hypothesis that the 1.8 and 1.5 Me/Si materials are internally crosslinked to a high degree, and are probably spherical in shape. The solvent‐polymer interaction parameters for the linear polymer in several solvents are calculated, and estimates of the solubility parameters of the various polysiloxanes are obtained.
Equal reactivity of amide groups in acid hydrolysis of polyamides from ϵ‐aminocaproic acid
Authors: Heikens D. 
Published: April 2003

AbstractSamples of the linear dimer and trimer and of a mixture of linear oligomers of ϵ‐aminocaproic acid with a mean degree of polymerization of 15, being free of lower oligomers up to the pentamer, were hydrolyzed in aqueous 7.72 N HCl at 110°C. for chosen time intervals. It is shown that the rate constant pertaining to the hydrolysis of the amide groups is independent of chain length and has the value of 0.24 hr.−1, proving that in the system investigated the principle of equal reactivity holds.
Allyl polymerization. IV. Effective chain transfer in polymerization of allylic monomers
Authors: Gaylord Norman G. 
Published: April 2003

AbstractIn addition to degradative chain transfer, effective chain transfer is characteristic of the polymerization of allylic monomers. The order of increasing effective chain transfer in a series of allyl compounds is ethyl ether < ethyl carbonate < acetate < propionate < trimethylacetate < chloride < laurate < benzoate < chloroacetate, and varies from 3% in allyl ethyl ether to 85% in allyl chloroacetate. A constant value of dM/dC is obtained in all of these cases. The decreasing order of [dM/dC]cat←0 is chloroacetate > benzoate > laurate > chloride > propionate > acetate > ethyl carbonate > trimethylacetate > ethyl ether and ranges from 108 for the chloroacetate to 6.3 for the ether. The decreasing order of DP is ethyl carbonate > acetate > propionate > benzoate > chloride > chloroacetate > laurate > trimethylacetate > ethyl ether and ranges from 14 for the carbonate to 4 for the ether. A radical displacement reaction may be operative in the polymerization of the trimethylacetate and benzoate and possibly in the case of the ethyl carbonate and ethyl ether. Considerable effective chain transfer occurs in the polymerization of allyl chloride and allyl chloroacetate as the result of hydrogen abstraction to yield halogen‐containing radicals. Effective chain transfer is predominant in the polymerization of allyll laurate, possibly through the operation of an intramolecular hydrogen transfer.
Infrared spectra of high polymers. IV. Polyvinyl chloride, polyvinylidene chloride, and copolymers
Authors: Krimm S. , Liang C. Y. 
Published: April 2003

AbstractThe infrared spectra of polyvinyl chloride, polyvinylidene chloride, and their copolymers have been analyzed with the help of group theory and of spectra in the extended range of 70 to 3000 cm.−1. The assignments of the bands have been made with the help of polarized spectra of oriented samples. For both polyvinyl chloride and polyvinylidene chloride the tentative structure suggested by x‐ray diffraction studies has been used as a basis for predicting the infrared spectrum of the polymer. In both cases a quite satisfactory interpretation of the spectrum has resulted, thus lending further support to the postulated structures. For each polymer, the group theory analysis is used to obtain selction rules and the distribution of normal modes among the symmetry species. On the basis of approximate separability of group modes, it is possible to analyze in detail the expected hydrogen, chlorine, and skeletal normal modes. Assignments of these frequencies are inferred from this information, knowledge of the region in which the normal frequency is expected to occur, and the polarization properties of the bands. In the case of the skeletal modes, the assignments are based upon recent calculations of the skeletal frequencies expected in long chain molecules.
Viscosity of dilute solutions of linear and branched polyvinyl acetate
Authors: Hobbs L. M. , Kothari S. C. , Long V. C. , Sutaria G. C. 
Published: April 2003

AbstractThe dilute solution viscosity properties of fractions of two linear and one branched sample of polyvinyl acetate in benzene and of two linear and one branched fraction in several solvents were measured at 35°C. Values of total slope, b (from plots of ηsp/c vs. c), and intrinsic viscosities were obtained under the requirement that k′ + β = 0.500 ± 0.002. Empirical plots of log b vs. log [η] gave lines which were straight within the limits of accuracy of the data. For the linear fractions in benzene, Huggins' k′ was constant and the slope of the log b vs. log [η] line was 2; for the branched fractions in benzene, k′ increased with [η] and the slope of the log b vs. log [η] line was greater than 2. The log b vs. log [η] plots form the basis for a “one‐point” method for determining [η]. Consideration of these data along with results reported in the literature indicates that k′ is measurably sensitive to branching only for fractions possessing a certain minimum combination of size and complexity. However, in some cases where the variations of k′ are inconclusive, use of the slope of the log b vs. log [η] line may provide a reliable indication of branching. It was found that a comparison between the branched and linear series could also be made at constant values of [η] or b. Two linear fractions in different solvents obeyed a type of Huggins relationship in which k′ did not vary with solvent and the slope of the log b vs. log [η] line was 2. For a higher molecular weight branched fraction, however, k′ varied from solvent to solvent and the slope of the log‐log plot was about 1.7. These data do not support a reference point concept of “true” intrinsic viscosity based on a simple linear relationship between b and [η]. Preliminary results dealing with the effects of the shear rate indicated that the measured viscosity properties of branched fractions may be more seriously affected by changes in shear rate than those of linear fractions.
Infrared spectra of high polymers. V. Polyvinyl alcohol
Authors: Krimm S. , Liang C. Y. , Sutherland G. B. B. M. 
Published: April 2003

AbstractThe infrared spectrum of polyvinyl alcohol has been investigated between 3600 and 70 cm.−1. Polarization measurements on stretched specimens were made down to about 330 cm.−1. The spectrum of a deuterated specimen (about 90% of the OH having been replaced by OD) has also been obtained. These data confirm and extend the results of previous workers. The spectrum is discussed in detail in relation to three structures for polyvinyl alcohol proposed on the basis of x‐ray diffraction studies. The data definitely rule out the structure proposed by Mooney, and are most consistent with the structure proposed by Bunn. A complete assignment of the bands in the spectrum is proposed. From this analysis it appears that the existence of interaction forces between molecules can be convincingly demonstrated. The proposed assignments suggest a new interpretation of the 1326–1446 cm.−1 doublet, viz., that these bands arise from mixed CH and OH in‐plane bending vibrations. This is shown to be in agreement with the results of studies on simple alcohols. An alternative assignment for the 1144 cm.−1 band is also considered.
Pyrolysis of polyacrylonitrile
Authors: Burlant W. J. , Parsons J. L. 
Published: April 2003

AbstractPolyacrylonitrile of molecular weight 130,000 has been pyrolyzed under nitrogen, between 200° and 320°. The predominant gaseous products are hydrogen cyanide and ammonia; the rates of formation of these have been measured, and at 270° for example, after 300 minutes, only 10% of the available nitrogen is lost. A liquid distillate containing nitriles, amines, and unsaturated groups was also obtained. Using infrared absorption measurements, it was found that the nitrile groups of the polymer disappear as heating progresses, and CN linkages appear. As heating is continued, evidence for aromatization is found. These experimental facts indicate ring formation to be an important reaction; the heat‐stable residues are considered to be mainly fused pyridine systems.
Studies on heterogeneous polymeric systems
Authors: Merz E. H. , Claver G. C. , Baer M. 
Published: April 2003

AbstractThe physical and morphological properties of heterogeneous mixtures of polystyrene with styrene: butadiene copolymers were determined. A mechanism of ultimate failure is proposed which permits the qualitative rationalization of the effects of copolymer composition, structure, and concentration upon certain physical properties of the mixture.
Un nouveau consistomètre à large gamme de gradients et de température
Authors: Kepes M. 
Published: April 2003

AbstractOn donne la description détaillée d'un appareil destiné à faire des mesures continues de viscosités sur de petites quantités de produits (1 à 4 cm3), dans la gamme de 0,01 à 108 poises. L'échelle des températures s'étend de −70° à +350°C.; sa limite supérieure rend le consistomètre particulièrement apte aux investigations sur les polymères fondus. L'appareil est du type tournant, à cône et plan, avec un anneau de garde. Le gradient de vitesses, constant à moins de 0,5% près dans l'entrefer, peut etre réglé de 10−3 à 103 sec−3, en 24 positions. Il est possible de travailler en atomosphère inerte ou sous vapeur saturante. On cite quelques exemples qui illustrent ses possibilités.
Formation of films from polymer dispersions
Authors: Brown George L. 
Published: April 2003

AbstractPolymer emulsions will undergo film formation upon loss of water if the driving force provided by capillary pressure is sufficient to overcome the resistance of the polymer particles to deformation. The conditions for film formation are expressible in terms of the surface tension and particle size of the dispersion, the time available for the drying process, the temperature, and the rheological properties of the polymer.
Effect of branching on dynamic mechanical properties of polyethylene
Authors: Kline D. E. , Sauer J. A. , Woodward A. E. 
Published: April 2003

AbstractThe effect of chain branching on the dynamic mechanical properties of polyethylene within the temperature region 80 to 380°K. has been studied using an apparatus which drives rod‐like specimens in their transverse modes. The results for three types of polyethylene having 3.2, 1.6, and less than 0.1 branches per 100 carbon atoms of the main chain are compared and discussed. Experimental results indicate that all of the three main dispersion regions (α, β, γ) characteristic of polyethylene are affected to some extent by branching. The β region, starting near 230°K., decreases with decreased branching, and for polyethylene which has negligible branching it is almost entirely absent. This suggests a direct relation between the number of branch points and the size and shape of this peak. The γ dispersion region near 170°K. appears sharper and shifted to higher temperatures with decreased branching, this being attributed to a narrowing of the relaxation times associated with the movement of a small number of CH2 units. The α dispersion region near 370°K. is also shifted to higher temperatures with decreased branching in accord with the shift of melting temperature with degree of crystallinity.
Linear phenol‐formaldehyde polymers—dehalogenation of p‐chlorophenol‐formaldehyde polymers
Authors: Burke W. J. , Ruetman S. H. , Stephens C. W. , Rosenthal Alex 
Published: April 2003

AbstractHigh molecular, linear phenol‐formaldehyde polymers were prepared by the dehalogenation of the corresponding p‐chlorophenol‐formaldehyde polymers with sodium in liquid ammonia. The phenol‐formaldehyde polymers and their acetyl derivatives were soluble in acetone and N,N‐dimethylformamide. Infrared studies were consistent with a structure having methylene bridges between the ortho positions of the phenolic residues.
Electron irradiation of polyacrylates
Authors: Shultz Allan R. , Bovey Frank A. 
Published: April 2003

AbstractThe crosslinking and degradation of seven polyacrylates by 1000 kvp. electrons has been investigated. Gel content‐radiation dose analysis reveals the energy dissipation per main‐chain fracture, Ed, to be the same (530 ± 100 electron volts) for methyl, n‐butyl, sec‐butyl, isobutyl, and tert‐butyl acrylate polymers. The energy dissipation per crosslinked unit formation, Ec, is 80–90 e.v. for methyl, n‐butyl, isobutyl and neopentyl acrylate polymers. Ec may be slightly higher for poly‐sec‐butyl acrylate. Poly‐tert‐butyl acrylate possesses a uniquely high Ec of 300 e.v. The presence of hydrogen atoms alpha to the alcoholic oxygen of the ester group is believed to contribute strongly to the crosslinking reactions of polyacrylates under ionizing radiations. Poly‐1,1‐dihydroperfluorobutyl acrylate exhibits an initial Ec of ∼45 e.v. and an Ed of ∼450 e.v. Beyond 15 megareps the ration of main‐chain fracture to crosslink formation increases.
Viscosités des solutions de molécules à chaîne courte
Authors: Rempp P. 
Published: April 2003

AbstractDans le but d'étudier le comportement physicochimique de diverses molécules à chaǐne courte, monodisperses et sans ramifications, nous avons fait une série de mesures viscosimétriques comparatives sur des paraffines normales d'une part, et d'autre part sur des dérivés oxygénés: éthers, dialcoxyalcanes, dialcoxydiéthyléther, etc… Toutes ces mesures ont été effectuées en solution diluée, dans le tétrachlorure de carbone et dans le benzène. Les résultats font apparaǐtre que: (1) Dans le cas des paraffines la viscosité intrinsèque devient négative si la chaǐne comporte moins de dix chaǐnons. Les résultats expérimentaux sont valablement représentés par une loi de la forme [η] = − A + B ln N. (2) Le remplacement d'un CH2 par un atome d'oxygène entraǐne une augmentation de [η]. L'ensemble de nos résultats—paraffines et dérivés oxygénés—peut ětre représenté par une loi de la forme

A et B étant des fonctions du rapport du nombre d'atomes d'oxygène au nombre total de chaǐnons de la chaǐne. (3) Le comportement des deux solvants étudiés à l'égard de tous leurs solutés est rigoureusement comparable.