bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and properties of a new polyether: Poly‐3,3‐bis(chloromethyl)‐1‐oxabutene
Authors: Farthing Alan C. , Reynolds R. J. William 
Published: April 2003

Abstract3,3‐Bis(chloromethyl)oxacyclobutane may be polymerized in the presence of powerful electrophilic catalysts, e.g., boron trifluoride; minute traces of water are also necessary for polymerization to proceed. The resulting polyether, poly‐3,3‐bis(chloromethyl)‐oxabutene, is an inert, highly crystalline and insoluble polymer, m.p. 180°, capable of forming oriented films and fibers. The high crystallinity and strong interchain forces are reflected by the complete inconsistency of solution viscosity values measured at 100°. The molecular weights could only be compared by determining melt viscosity values.
Some aspects of the polymerization of fibrinogen
Authors: Ferry John D. , Katz Sidney , Tinoco Ignacio 
Published: April 2003

AbstractThe polymerization of activated fibrinogen takes place in two stages. First, the monomer units form intermediate polymers with twice the original cross‐section area and about eight times the original length. The polymers have been detected under a variety of conditions between pH 6.1 and 10. The polymerization geometry is believed to be lateral dimerization with a staggered configuration, determined by a pattern of electrical charges. The negatively charged groups, though unidentified, appear to be near histidine residues, as deduced from the dependence of polymerization on pH. The positively charged groups, from this and other evidence, appear to be α‐amino groups. Second, the intermediate polymers unite to form the strands of the fibrin network. This association appears to involve nonpolar groups, and the width of the final strands, unlike that of the intermediate polymer, depends markedly on the net charge as determined by the pH.
The role of free radicals in the degradation of high polymers by ultrasonics and by high‐speed stirring
Authors: Alexander P. , Fox M. 
Published: April 2003

AbstractHigh molecular weight polymethacrylic acid in aqueous solution is rapidly broken down by ultrasonics (250 kc.). The rate of degradation varies as the shape of the molecule in solution is altered and is greatest when most asymmetric.It is concluded that cavitation is essential for the breakdown of the polymer molecules and that the reaction proceeds by two mechanisms. The major part of the reaction is due to mechanical forces produced on the collapse of the cavity but chemical degradation by HO2 radicals also occurs. Polymerization experiments confirm that free radicals are formed during cavitation. The quantity of H2O2 formed by ultrasonics is much greater than the number of free radicals produced and a separate mechanism for its formation must be postulated. High‐speed propellers, e.g., in a “Waring Blendor,” bring about cavitation and degradation of polymethacrylic acid.
Thermal and oxidative decomposition of polyvinyl chloride
Authors: Arlman E. J. 
Published: April 2003

AbstractAn investigation into the kinetics and the mechanism of thermal and oxidative decomposition of polyvinyl chloride is reported. The rate of HCl evolution was measured in streams of nitrogen, air, and oxygen. The reaction is described as a chain reaction involving initiation (thermal and oxidative), propagation, and termination (spontaneous and oxidative). A Kinetic scheme is given representing the rate of HCl evolution as a function of the reaction constants of the step reactions. The results indicate that thermal decomposition starts at the end groups of the macromolecules, whereas oxygen initiates decomposition within the chain.
Herstellung und eigenschaften von polygalakturonsäureamiden
Authors: Solms J. , Deuel H. 
Published: April 2003

AbstractPolygalakturonsäuremethylester verschiedener Veresterungsgrade können durch Behandlung mit flüssigem Ammoniak im Autoklaven bei 16°C. während 24 Stunden annähernd quantitativ in die entsprechenden Amide übergeführt werden. Die Amide sind in Wasser schwer löslich und ergeben Lösungen geringer Viskosität. Sie können aus ihren Lösungen durch Elektrolyte leicht koaguliert werden. Derivate mit einem Amidierungsgrad von über 70% sind wasserunlöslich. Mit steigendem Amidierungsgrad können eine Erhöhung der Stabilität gegenüber dem Enzym Polygalakturonase. sowie eine Zunahme der Geliertendenz festgestellt werden. Die Amide bilden keine festen Gele. Die Eigenschaften der Amide werden stark durch ihre Fähigkeit zur Bildung inter‐ und intramolekularer Wasserstoffbrücken beeinflusst.
Size and shape of droplets of demixing polymer solutions in a field of flow
Authors: Silberberg A. , Kuhn W. 
Published: April 2003

AbstractThe phases which are formed at, e.g., 22°C., when a solution containing, e.g., 1.1% polystyrene and 1.7% ethyl cellulose is made in benzene, are characterized by having a low interfacial tension (⋍10−3 erg/cm.2), which permits droplets of the one phase in the other to be easily deformed and disrupted in a field of flow. The size and shape of the droplets thus formed were determined by an optical method depending upon the statistical addition of the deflections suffered by a beam of light in its passage through the medium. It is found that at intermediate velocity gradients very small and extremely elongated droplets are stable and that, at a given temperature, the phase separation can be reversed by raising the velocity gradient above a definite value. A full discussion of the observations is given and it is shown in particular that the appearance of extremely elongated drops at certain velocity gradients is due to a stationary state equilibrium between processes causing the drops to break up and others causing them to recombine again. The superposition of break‐up and recombination is thus responsible for the existence in practice of inherently unstable drop shapes.
Theory of strong polyelectrolyte solutions. I. Coiled macro ions
Authors: Ōsawa Fumio , Imai Nobuhisa , Kagawa Ikumi 
Published: April 2003

AbstractA new theory of strong polyelectrolyte solutions based upon the Poisson‐Boltzmann equation is presented. Assuming that the ratio of the effective charge of the macro ion to its original charge is very small, the Poisson‐Boltzmann equation is solved without adopting the Debye‐Hückel approximation. As a result of the calculation, the effective charge of the actual coiled macro ion with the strongly dissociative groups was found small enough to justify this assumption for the solutions of varying concentration over wide range. Moreover, the free energy, and consequently the chemical potential of the components, of the polyelectrolyte solution with or without simple salt are calculated. The idea of “ion fixation” is theoretically introduced as convenient for representing the state of the polyelectrolyte solution. The theoretical results obtained above are quantitatively compared with experimental data with very good agreement.
Preparation and properties of poly‐p‐xylylene
Authors: Corley Richard S. , Haas Howard C. , Kane Marshall W. , Livingston Daniel I. 
Published: April 2003

AbstractThe preparation of poly‐p‐xylylene, , in 24–26% yield, by pyrolysis of p‐xylene, is described in detail. The nature and amount of by‐products of the pyrolysis were determined. The physical appearance and the following properties and reactions of the polymer are described: x‐ray diffraction, crystallinity, optical constants, infrared absorption spectrum, degradation by autoxidation in solvents and by pyrolysis, dielectric constant and loss, sulfonation and chlorination. The significance of this data is discussed relative to an understanding of the mode of formation and the structure of the polymer.
Vinyltoluene‐styrene copolymer sulfonic acid. I. Viscous properties and ionic character in hydrochloric acid solutions
Authors: Mock Richard A. , Marshall Charles A. 
Published: April 2003

AbstractAssuming complete dissociation of the mineral acid in dilute aqueous solutions of a 1:1 vinyltoluene‐styrene copolymer sulfonic acid and HCl, the degree of dissociation of the polyacid is apparently a constant independent of the concentration of either solute. On the basis of this result, it is likely that the polysulfonate chain initially contracts in such a manner with increasing HCl content of the solution that a maximum number of sulfonate groups remains on the surface of the coil. The variation of reduced viscosity (ηsp/c) with polyelectrolyte concentration c in the presence of a finite quantity of added “normal” electrolyte is determined mainly by the ratio of the counterions resulting from polyelectrolyte dissociation to the total counterion content of the solution. In regions of high dilution, where counterions from the polyelectrolyte are much less numerous than those from HCl, an apparently linear increase of reduced viscosity with increasing polymer concentration is observed. These data probably can be extrapolated to infinite dilution. Over the range of HCl concentrations 10−4 to 10−2 equivalent per liter the reciprocal square root of such extrapolated polysulfonic acid “limiting viscosity numbers” is proportional to the pH of the solvent. At the maxima of reduced viscosity plots the contribution of the polyelectrolyte to the hydrogen ion activity of the solution is half the contribution of the HCl: i.e., one third of the hydrogen ion activity is the result of polyelectrolyte dissociation. Moreover, the reduced viscosity at the maximum is directly proportional to the pH of the solvent. Curves of ηsp/c vs. c at high dilutions and constant pH are parabolas rather than straight lines. It is permissible to postulate rather convincingly from our data that the reduced viscosity curve of the polysulfonic acid in water possesses a maximum accurately indicated by the intercept of a Fuoss plot (cf. equation (7) in the text). The intercept of a Fuoss plot for any polyelectrolyte can have the significance of a limiting viscosity number only when measurements are made in a nonionizing solvent.
The microstructure of diene polymers. III. Polyisoprenes and polybutadienes prepared with cationic catalysts
Authors: Richardson W. S. 
Published: April 2003

AbstractA number of polyisoprenes and polybutadienes have been prepared at temperatures between 30° and −78°C. using Friedel‐Crafts catalysts. Quantitative analyses for the various types of addition occurring in these polymers have been made from their infrared spectra. It has been found that the linear structures corresponding to 1,4; 1,2 and 3,4 addition are present in about the same ratios as in free radical type polymers. However, in the case of the polyisoprenes (and apparently also the polybutadienes) these structures account for only about 50 to 75% of the material present.
Monolayer studies of some ethoxylin resin adhesives and related compounds
Authors: Glazer J. 
Published: April 2003

AbstractCompression isotherms of monolayers of ethoxylin resins and related compounds have been studied at the air–water interface, and the orientation of such monolayers at the interface has been described. The monolayer thickness has been measured by the multilayer technique. It has been shown that resin‐substrate adhesion is strongly dependent on the hydroxy group content of the resin, and is independent of the epoxy group content, the molecular weight, and the hydrocarbon group content of the resin. Furthermore, it has been shown that the presence of epoxy groups results in high intermolecular cohesion of the prehardened resin; this, in turn, will tend to minimize resin shrinkage during the hardening process and thus improve the joint strength.
Theory of mechanochemical systems
Authors: Asakura Shô , Imai Nobuhisa , Oosawa Fumio 
Published: April 2003

AbstractAn electrolytic theory is developed for the swelling and deswelling mechanism of mechanochemical systems by methods established by the authors, who are concerned with the problem of polyelectrolyte solutions. The model employed in the theory is a macroscopic cylindrical fiber of rubberlike material with many dissociative radicals. It is assumed, for the sake of simplicity, that the average charge density of the ionized radicals is spread uniformly inside the fiber. The result of the theory shows that almost all the gegenions are bound by the fiber, and that the contributions of the electrostatic energy and entropy to the electrostatic free energy are two‐ and three‐dimensional, respectively, when the density of the ionized radicals remains constant. In combination with theoretical results of rubberlike elasticity and of nonelectrolytic swelling, it is concluded that the osmotic pressure of the gegenions bound by the system makes the system swell against the restoring force due to the rubberlike elasticity of the system. The free swelling of systems is, for instance, expressed by the following relation:

where α is the relative elongation, N the number of the dissociative radicals per chain ξ the degree of neutralization, and B the factor due to the full stretching effect of each chain. This relation is in good agreement with experimental results.
Application of rhodamine‐B to interaction studies in proteins and simple model systems
Authors: Lundgren Harold P. , Binkley Charles H. 
Published: April 2003

AbstractWith rhodamine‐B used as an indicator, the relative acidities of selected phenols and alcohols as model hydrogen donors have been determined in toluene solution. The method involves measurement of the change from colorless rhodamine to the colored zwitterionic form produced by the hydrogen donor compound. The method has been applied to the determination of equilibrium constants for the interaction of phenol with dimethyl formamide, benzyl acetate and dioxane; the measured constants are in accord with those obtained for the same pairs by Flett (J. Soc. Dyers Colourists, 68, 59–64 (1952)), who employed infrared analysis. Consideration is given to partition of the dye between toluene and water, as influenced by hydrogen bonding and by nonelectrostatic interactions. Forces of interaction which tend to bind the dye in one phase decrease its activity in that phase and consequently reduce its tendency to move from this phase to the other. With incorporation of propiolactone polymer into the wool fiber, the activity of the dye in the fiber is reduced in relation to nonpolar as well as to aqueous solutions, and the modified wool exhibits greatly improved dyeing properties. The dye is useful also for the determination of critical micellar concentration of fatty acid soaps in aqueous solution. It also shows markedly increased binding by heat‐denatured as compared with native egg albumin, and by acetylated, as compared with normal, wool.
Vulcanization of crepe rubber by sulfur monochloride. Part I. The gelation method
Authors: Glazer J. , Schulman J. H. 
Published: April 2003

AbstractWhen a solution of natural rubber hydrocarbon is cold vulcanized with sulfur monochloride, a gel is formed. The rate of gel formation is used to characterize the rate of reaction between rubber and sulfur monochloride and a preliminary kinetic investigation is described. It is shown that the reaction is accelerated by compounds normally used for speeding up sulfur (hot) vulcanization, and it is suggested that these function by virtue of their possessing an active hydrogen atom. Several series of simple compounds, containing the groups SH, OH, and NH2, are shown to function as effective accelerators and their activity is attributed to the presence of a labile hydrogen atom in the molecule RXH, where R = organic radical and X = S, O, or N. The absence of a direct relationship between accelerating power and basic or acidic strength suggests a free radical mechanism of accelerator action, based upon the process
${\rm R} - {\rm X} - {\rm H } \to {\rm R} - \mathop {{\rm X }}\limits^ * {\rm + }\mathop {{\rm H }}\limits^ * $.
Thermodynamics of the mechanical properties of cellulose fibers
Authors: Roseveare W. E. , Poore L. 
Published: April 2003

AbstractMeasurements are reported for the reversible changes in force with temperature at constant length of wet and dry viscose rayon and wet ramie. It was found that the force was a reversible function of the temperature although the components of its thermodynamic equivalent, the product of modulus and coefficient, are very time dependent. The entropies of stretching obtained as the negative slopes of the force‐temperature curves are interpreted in terms of the mechanisms of reversible stretching. Completely dry rayon is glasslike and shows no slippage of chains but only deformation of valence bonds and angles on reversible stretching. Wet rayons exhibit a rubberlike slippage of chains above 50°C. but below this temperature chain movement is restricted. This inhibition of the chains produces at low temperatures a yield point in the wet stress‐strain curves and poor work recovery. Sodium hydroxide, although speeding up stress relaxation, has no effect on the reversible stretching of the amorphous wet cellulose. In room air, the entropy of stretching is opposite to that of completly dry rayon even up to 92°C. Wet ramie appears to be in the glassy state like the completely dry rayon.
Breakage of rubber‐filler linkages and energy dissipation in stressed rubber
Authors: Blanchard A. F. 
Published: April 2003

AbstractThe stress–strain behavior of reinforced rubber is discussed in respect of the softening with applied stress and accompanying dissipation of energy. The concept of linkage strength factors X for attachments between rubber molecules and filler particles is shown to have wide application and usefulness, and to be related to the energy dissipated in breaking the linkages. The strength factors are a function of the prestress when the linkages break, and also the corresponding extension ratio and residual stiffness; and for a variety of fillers and considerable range of values they can be roughly converted to energies of breakage in calories per unit change in modulus by multiplying by η = 0.013. The range of strengths of these secondary linkages due to fillers may be expressed in terms of X by one distribution parameter K common to widely different rubber compounds. Energy data suggest that they are formed by physical attachments involving a number of chemical groups in the long chain polymer molecules. Presumably the strength distribution is mainly due to differences in the number of groups involved. The particle diameter of the filler has little or no importance in determining the energy dissipated in breaking secondary linkages, or their number as judged by stiffening action; yet it is a major factor in reinforcement as judged by tensile strength, tearing, and abrasion. Considerations of secondary linkages in conjunction with particle diameter show no prospect of explaining the differences in reinforcing action between types and grades of filler. An appreciation of the presence of some of strong‐type (primary) linkages due to carbon black is apparently necessary to understand the wide differences between fillers in the energy dissipated on breaking secondary linkages by a fixed prestress.
Solvent independent parameters in the viscometry of polymer solutions
Authors: Cleverdon D. , Smith P. G. 
Published: April 2003

AbstractEvidence is discussed for and against the existence of a common meeting point when linear plots of ηsp/C against C for polystyrene in a number of solvents are extrapolated to negative concentrations. There is rather more evidence in favor than against, and most of the contrary evidence falls into a category for which exceptional behavior might be anticipated. The ordinate of the common meeting point, unlike the limiting viscosity number, is independent of solvent and is conveniently called the true limiting viscosity number [η]T. [η]T has been identified with the intrinsic configurational character of a polymer chain. The common point of intersection has the coordinates [η]T and C2, where Cx is a negative concentration. The product of [η]T and Cx has been found to be constant over a considerable molecular weight range. This leads to an expression for [η]/[η]T in terms of Huggins' k′. [η]/[η]T represents the ratio of the hydrodynamically equivalent volume of a polymer in an actual solvent to the equivalent volume of the chain in its natural state of extension. [η]T is considered in relation to [η]θ (Flory‐Fox) and [η]P (Bawan). The effect of polymer heterogeneity is discussed.
A thermostat for light scattering measurements
Authors: Casassa Edward F. , Katz Sidney 
Published: April 2003

AbstractA thermostat for light scattering studies is described in which the glass cell containing the solution under investigation is immersed in water maintained at constant temperature. The construction is such that the phototube used for detection of scattered light is at room temperature whatever the temperature of the sample. The liquid bath about the sample cell minimizes both troublesome reflections of the incident light and errors arising from refraction effects.
Small angle x‐ray scattering of rayons swollen in lithium hydroxide solutions
Authors: Hermans P. H. , Weidinger A. 
Published: April 2003

AbstractIn continuation of a previous investigation on the small‐angle scattering of rayons in the dry and water‐swollen condition, a number of samples are investigated in lithium hydroxide solutions of increasing concentration up to 5 N, in which considerably higher degrees of swelling can be reached. In samples showing an intensity maximum in the water‐swollen condition, the locus of this maximum shifts to smaller angles upon further swelling in LiOH solutions, to disappear in 5 N solutions. Samples exhibiting neither a maximum nor an inflection point in no case yield straight Guinier plots even at the highest degree of swelling attained.
Hydrodynamic properties of urea‐denatured fibrinogen
Authors: Scheraga H. A. , Carroll W. R. , Nims L. F. , Sutton E. , Backus J. K. , Saunders J. M. 
Published: April 2003

AbstractThe hydrodynamic properties of native and urea‐denatured fibrinogen have been investigated, primarily to examine further the suggestion, based on a consideration of data for horse serum albumin, that urea denaturation may involve swelling instead of increased asymmetry. A sedimentation‐diffusion and also a light scattering molecular weight determination at the isoelectric point indicate that 6 M urea causes neither splitting nor aggregation of the native protein in the denaturation process. The observed increase in the intrinsic viscosity and frictional coefficient upon denaturation can be interpreted in terms of an equivalent hydrodynamic ellipsoid of approximately the same shape but of a volume which is approximately 1.7 times that for the native protein. The effective volume appears to be slightly dependent on pH with a minimum at the isoelectric point. It thus appears that the urea denaturation of bovine fibrinogen, like that of horse serum albumin, may involve swelling. There is no indication in the case of either protein that increased asymmetry is involved in accounting for the frictional behavior of the denatured substances.