bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE EFFECT OF MIXED FILLER SIZES ON THE FIBER DIAMETER OF ELECTROSPUN BUTYL RUBBER FORMULATIONS
Authors: Murphy Dan , Barry Carol , Mead Joey , Zukas Walter 
Published: February 2011

Abstract
Electrospinning of thermosetting elastomers is a method for developing nonwoven membranes with a microporous structure for use in dynamic applications (i.e., stretchable). These membranes have potential for chemical protective clothing applications. The most challenging concerns are the ability to control pore sizes, fiber diameter, permeability, and physical properties. We investigated the effect on fiber diameters as a ratio of two different carbon black particulate sizes. Carbon black N110 and N990 were incorporated at various percentages of total carbon black loading in a butyl rubber formulation. Higher levels of small particulates were found to give smaller and more consistent fiber diameters. Understanding of the effects of filler size and concentration on the electrospinning process will lead to the successful tailoring of nonwoven membranes with desired fiber diameter and pore size.
MULTIPLE GLASS TRANSITION TERPOLYMERS OF ISOPRENE, BUTADIENE, AND STYRENE
Authors: Halasa Adel F. , Gross Bill B. , Hsu Wen-Liang 
Published: February 2011

Abstract
Novel polymers that will contribute to a better combination of traction and tread wear in tire applications, which is historically difficult to achieve, have been developed. In this work, multiple viscoelastic polymers possessing multiple glass transition temperatures terpolymers of isoprene/butadiene/styrene were synthesized containing 45/45/10, 40/40/20, and 35/35/30 polymer ratios in 5-gallon laboratory reactors using tetramethylethylenediamine or bis(dipiperdino) ethane as a modifier. These polymers show two glass transition temperatures (Tg's); the one that occurs at higher temperatures (–25 to –10 °C) is known to contribute to good wet traction properties, while the lower Tg is known to contribute to better tread wear properties. These terpolymers were characterized by the fact that their multiviscoelastic loss modulus has narrow molecular distribution for better rolling resistance. In a standard ASTM D31912 carbon-black-filled tread compound recipe, the polymers having all three terpolymers of isoprene/butadiene/styrene polymerized showed excellent values of loss tangent at 0 and 60 ºC, which is a laboratory predictor for both wet traction and rolling resistance. These terpolymers when evaluated in the same ASTM D3191 delivered better properties in a tread compound recipe than either solution or emulsion styrene-butadiene rubber in a formulation that has natural rubber or polybutadiene.
PLASMA POLYMERIZATION OF MONOMERS ONTO FILLERS, TO TAILOR THEIR SURFACE PROPERTIES IN TIRE COMPOUNDS
Authors: Dierkes W. K. , Tiwari M. , Datta R. N. , Talma A. G. , Noordermeer J. W. M. , van Ooij W. J. 
Published: February 2011

Abstract
Rubber reinforcement by fillers is primarily based on filler structure and surface properties. A chemical change of the surface properties while maintaining the structure allows tailoring filler properties for improved filler–polymer compatibility, resulting in improved morphological, dynamic, and mechanical properties of straight rubbers as well as elastomer blends. Plasma polymerization based on acetylene, pyrrole, and thiophene as monomers are applied to silica in order to change surface polarity and chemistry, with untreated and silane-treated silica as references. Generally spoken, the plasma coating results in reduced filler–filler interaction, improved dispersion, and increased bound rubber content in straight SBR as well as in SBR/EPDM blends. In terms of stress-strain properties, the plasma treatment results in higher moduli compared to the untreated filler. The most prominent effect was found in the stress-strain properties of straight SBR: Polythiophene-coated silica results in significantly higher moduli and tensile strength values, even higher than the silane-treated material. In the case of the polymer blend, the plasma treatment results in higher tensile strength and elongation at break values. It is important to note that no unambiguous correlation was found between filler–filler interaction and filler–polymer interaction: A lower Payne-effect does not necessarily result in a higher bound rubber content.
Dynamic Fatigue Life of Rubber
Authors: Cadwell S. M. , Merrill R. A. , Sloman C. M. , Yost F. L. 
Published: February 2011

Abstract
If a rubber member is continuously vibrated it will sooner or later crack and ultimately rupture, owing to the repeated oscillations to which it has been subjected. The gradual deterioration of physical and chemical properties which accompanies such vibration is called dynamic fatigue. The number of such repeated vibrations required to rupture the rubber member is here defined as the dynamic fatigue life of the member for the particular condition of vibration imposed. The authors wish to outline briefly the general nature of the results they have obtained in their studies on the dynamic fatigue life of rubber and, in particular, to show the critical dependence of the life on the imposed oscillation conditions. The dynamic fatigue life of rubber which is being vibrated linearly, that is, back and forth along its own length, between constant strain limits will be discussed first. Figures 1 to 3 facilitate a general statement of the problem and also serve to define certain oscillation limits which are of fundamental importance with reference to dynamic fatigue life. The sketches are conventionalized for the sake of simplicity.
Some Remarks on the Measurement of the Viscosity of Latex by Means of a Capillary Viscometer
Authors: Van Gils G. E. 
Published: February 2011

Abstract
In this article the paper of Jordan, Brass and Roe is criticized. The theoretical basis of viscometry is explained, and it is shown that Poiseuille's law can be derived in the case of a true or Newtonian liquid flowing through a capillary tube. It is not permissible, however, in dealing with a non-Newtonian liquid, to use any equation based on Poiseuille's law, as was done by Jordan, Brass and Roe. The Crude Rubber Committee of the Rubber Division of the American Chemical Society has realized clearly the importance of uniformity in viscometry, but we must warn very strongly against methods based on unsound reasoning. We also find some fundamental objections to the paper by Kendrov.
The Investigation of Synthetic Linear Polymers by X-Rays
Authors: Fuller C. S. 
Published: February 2011

Abstract
The ultimate aim of research on high polymeric substances is to explain the properties of these substances in terms of their inner colloidal and molecular nature. x-Eay and electron diffraction investigations, as we have seen, have furnished considerable data on this inner structure. Nevertheless, it is of the utmost importance that the investigator in this field does not obtain a one-sided view from the past work. Nearly always a given study relates to only one phase of the general problem. For example, it is wrong to assume that, since the “unit cell” for cellulose has been well established, we therefore know its entire structure. In reality we have determined simply that parts of the cellulose have this structure. How these parts fit into the other parts that make up the entire system is still not clear. Here again the synthetic high polymers can be of great help. By employing simple polymeric molecules of known chemical constitution and structure, and by determining how these molecules behave in the aggregate, we may expect to make progress in understanding these complex systems. In this endeavor a closer control of both the specimens under examination and the technique itself will serve to make the diffraction method an even more valuable tool for the study of high molecular compounds.
Swelling Measurements in the Rubber Laboratory
Authors: Proske G. 
Published: February 2011

Abstract
In making swelling measurements, which are carried out with great frequency today in rubber laboratories, the most varied procedures are in general use, some of which do not bear careful and critical examination. The most important sources of error, which occur equally in all the methods, are first discussed, then follows a detailed discussion of commonly used methods, particularly the gravimetric and volumetric methods in their various modifications. Especially useful methods are pointed out. The attempt is made to make the discussion clear by means of representative rubber mixtures chosen from practice. Finally an experimental apparatus developed by the author from apparatus already in technical use and well suited to rubber laboratories is described in detail.
Effect of Strain on the Aging of Vulcanized Rubber
Authors: Dawson T. R. , Scott J. R. 
Published: February 2011

Abstract
Vulcanized rubber which is stored in a state of strain deteriorates much more rapidly than similar rubber not under strain. This observation has immediate application to rubber goods of many kinds, such as tire tubes packed in a folded state, tires standing under strains due to their own weight or to that of the vehicle, coiled and bent cable and hose, football bladders and bathing caps packed flat, folding-boat covers, and so on. There has been a moderate amount of investigation devoted to this phenomenon in the last two decades, but, in the main, quantitative studies have been devoted to simply stretched rubber, and data on the effects of folds or creases have not been available. As folds and creases involve compression as well as stretching, it cannot be assumed that conclusions drawn from studies of stretched rubber are applicable without change to rubber articles subjected to folding or creasing. The observations given in the present paper, made on different occasions in connection with other work, bring together several examples of the effect of folds on the aging of rubber.
Rational Processing
Authors: Cotton F. H. 
Published: February 2011

Abstract
The processes to which rubber is subjected before vulcanization depend largely for their success on the raw material being rendered plastic. At ordinary temperatures smoked sheet is an elastic substance having nerve and incapable of being kneaded, extruded or moulded. To facilitate these processes and compounding with fillers, rubber is masticated, either on a two-roll mill or in an internal mixer. Experience has shown that mechanical working reduces the elasticity and nerve of rubber and renders it plastic. Mastication is such a familiar practice in rubber technology that it is taken for granted as the first essential in rubber manufacture. This is unfortunate, because it is costly and has several disadvantages. These will be considered in detail and other means of achieving the same end suggested.
The Kinetics of the Polymerization of Isoprene on Sodium Surfaces
Authors: Bolland J. L. 
Published: February 2011

Abstract
In recent years an increasing amount of study has been devoted to gaining a better understanding of the fundamental nature of polymerization reactions. Perhaps the most successful method of approach so far employed has been the systematic study of the kinetics of a wide variety of polymerizations, thermal, catalytic and photochemical. As yet, however, little attention has been directed toward one very important type of polymerization, viz., the polymerization of conjugated compounds in presence of alkali metals. The kinetic method has therefore been applied to the polymerization of isoprene on sodium as a representative example of this class of reactions.
Mixed Polymers and Vulcanizable Plasticizers. Relation to the Vulcanization of Rubber
Authors: Garvey B. S. , Alexander C. H. , Küng F. E. , Henderson D. E. 
Published: February 2011

Abstract
The vital role played by rubber in modern civilization is due in part to the physical properties displayed by soft vulcanized rubber in service and in part to the characteristics of unvulcanized milled rubber which make it amenable to manufacturing operations. Vulcanization of rubber is a change in condition usually induced by heating it with sulfur, and is best defined by contrasting the difference in physical properties: To illustrate, compare a mill-mixed composition before and after vulcanization. Before vulcanization it is easily pulled apart and, if considerably extended, shows little tendency to retract, although, under impact, the recovery or rebound is considerable. If heated it becomes even softer and more plastic, and can easily be formed into any desired shape. If cooled to 0° C or somewhat lower, it becomes stiff and boardy. It is readily soluble in hydrocarbon solvents. When two fresh surfaces are pressed together, they coalesce and become practically integral. This tack, as it is called, is valuable in manufacturing operations. After vulcanization, rubber is tough and strong and, after even a slow distortion, returns rapidly to its original shape. It has little tendency to flow and is devoid of tack. It swells but does not dissolve in hydrocarbon solvents. These characteristics change very little from −40° to well above 100° C.
Frictional Properties of Rubber
Authors: Roth Frank L. , Driscoll Raymond L. , Holt William L. 
Published: February 2011

Abstract
Laboratory measurements of coefficients of friction of soft rubber compounds were made by towing specimens on horizontal tracks and by allowing them to slide down inclined tracks. The specimens were prepared by attaching the rubber to a metal backing and molding it against glass surfaces having different degrees of roughness. The coefficients increase markedly with speed, ranging from about 1 at 10−4 cm. per sec. to more than 4 at 5 cm. per sec. The occurrence of vibrations prevented observations at higher speeds. Static friction is greater than dynamic friction for speeds appreciably less than 10−3 cm. per sec. and less than dynamic friction for greater speeds. The coefficients decrease slightly with increasing pressures and are independent of the size of the specimen. Except at very low speeds the smoother surfaces yield the higher coefficients. Materials such as talc or bloom on the sliding surfaces cause large decreases in the coefficients. Attention is called to the dependence of the coefficients of friction on the speed, which is shown in several previous investigations on rubber and other materials.
Cryoscopic and Viscosity Studies of Polyisobutylene. Cryoscopic Deviation of Polyisobutylene Solutions from Raoult's Law
Authors: Kemp A. R. , Peters H. 
Published: February 2011

Abstract
1. The cryoscopic method is not satisfactory for polyisobutylenes having chain lengths much over 40 isobutylene units, on account of the failure of their solutions to obey Raoult's law. 2. The present work has led to the selection of a Kcm value of 0.75×104 for n-hexane solutions of polyisobutylene for use in the equation M=(log ηr×Kcm)/C. 3. Extrapolation of cryoscopic data obtained on nonideal solutions to infinite dilution gives inordinately high molecular weight values compared with those based on freezing point measurements of ideal solutions. 4. Of several solvents studied, n-hexane was found to be the best for viscosity—molecular weight measurements of polyisobutylene. 5. Fractionation of polyisobutylene by diffusion into mixtures of n-hexane and acetone resulted in the separation of the lower polymer fractions.
Growing Rubber in North America
Authors: Trumbull H. L. 
Published: February 2011

Abstract
Ever since war was forced upon us, with the subsequent capture by the Japanese of the Malay Peninsula and the Dutch East Indies, Americans have been groping for new sources of natural rubber to replace those cut off by our enemies. With startling dispatch, lands which produced 90 per cent of the crude rubber used by this country had been captured, and the supplies from another 7 per cent of the world's producing areas had been endangered by action against lines of communication with these sources. The problem was not entirely new, because many farseeing people, both in government service and private business, had been concerned about our dependence on distant sources for what had become one of our essential materials in peace and war. They had made studies of domestic plants which might produce rubber in quantities sufficient for our necessities. The urgency of the task, however, was not so great then as it is now. Early this year I was assigned by the Goodrich company to give this problem primary attention, and to call on any other resources of the organization for assistance whenever necessary. The purpose was to seek information and propose action which would benefit the nation, suffering under an acute shortage of natural rubber. The principal early parts of this work were the study and evaluation of all domestic plants known to produce rubber, and the discovery, if possible, of new sources of this vital material on our continent.
Distribution of Non-Rubber Substances in Preserved Latex Part II. Acids
Authors: Baker H. C. 
Published: February 2011

Abstract
In a previous paper by the present author, a general method for determining the distribution of the nonrubber substances between the rubber-and-water phases in latex was described and results were given of its application to the study of the distribution of nitrogen and materials extractable with acetone. It was shown that the nitrogen associated with the rubber phase is of two different types, a small amount (about 0.02 per cent) being independent of particle size and consequently distributed throughout the mass of the rubber, whereas the remainder is a function of particle size, replaceable by surface-active materials, such as soaps, and is, consequently, situated at the surface of the particles. The surface nitrogen in ammoniated latex was variable, decreased with age of latex, could be partially desorbed at an alkaline pH by washing the latex, for instance, by dilution or repeated creaming, and is considered to represent the protective protein covering of the latex globules. The total variation experienced in unconcentrated ammoniated latices of varying ages was from 0.11 to 0.18 per cent, but in latex of good quality about six months old, surface nitrogen was 0.15 per cent, corresponding to about 1 per cent protein. Distribution experiments on the acetone extract showed that there is from 2 to 3 per cent of acetone-soluble substances associated with the rubber, of which less than one-half represents ammonium soaps at the surface of the particles. The surface of the rubber particles is, therefore, composed largely of protein and fat acids, and it was thought probable that the ratio between them might change, both during the life of a single latex and from one latex to another.
The Phosphatides of Hevea Brasiliensis
Authors: Tristram G. R. 
Published: February 2011

Abstract
The presence of phosphatide in Hevea latex had long been suspected, but it was not until 1931 that Rhodes and Bishop isolated phosphatidic material containing 0.59 per cent nitrogen and 1.72 per cent phosphorus from the serum of latex which had been coagulated with ethanol. The crude material of these authors represented 0.2 per cent of the latex and, on treatment with acetone, yielded an insoluble fraction containing 0.88 per cent nitrogen and 2.56 per cent phosphorus (40 per cent of the former product). This latter fraction was, according to the accepted analytical composition of phosphatide, still very impure. The work of Rhodes and Bishop was repeated by Altman and Kraay, who isolated in very small amounts a product which gave much the same analyses, and extended the findings of Rhodes and Bishop by showing that the crude phosphatide contained both choline and glycerophosphoric acid. It is very probable that the phosphatide, although present in such small amount, is one of the important nonrubber components of latex. Judging from the ease with which phosphatides emulsify in aqueous media, there seems little doubt that the phosphatidic material assists in the maintenance of latex as a stable emulsion. It has been suggested by Bollman that crude phosphatide preparations act as natural antioxidants in vegetable oils. This suggestion has been disputed by Diemair and Fox and other workers, who state that this property is not possessed by pure phosphatide, although the complex system from which the phosphatide had been separated was an active antioxidant. Diemair, Strohecker and Reuland have advanced the opinion that the active antioxidant is a protein-phosphatide complex. The present work was undertaken as part of an investigation of the non-rubber components of latex. The crude phosphatide was prepared by the method of Rhodes and Bishop, the preliminary treatment being carried out at the Rubber Research Laboratories, Ceylon, under the direction of Mr. O'Brien, to whom the author's thanks are due. The raw material was treated by the method outlined below. The crude phosphatide was fractionated by a method which was essentially that used by Channon and Foster in their work on the phosphatides of wheat germ. The fractionation resulted in the isolation of a fairly pure form of phosphatidic acid (the possible source of which is discussed later) and an impure form of lecithin. The lecithin fraction contained little or no kephalin (only about 5.5 per cent of the nitrogen in this fraction was amino-nitrogen), a finding which was unexpected.
Oxidation of Rubber and Its Colloid-Chemical Results
Authors: Houwink R. 
Published: February 2011

Abstract
After the structure of raw and vulcanized rubber is discussed, the reactions which probably take place between the rubber molecule, oxygen and sulfur, in presence and absence of light, are indicated. Depending on circumstances, a severance of the molecule or net formation may be expected (dehydrogenation, formation of oxygen and sulfur bridges, cyclization) ; see Table 1. The accompanying changes in solubility, viscosity in solution, tensile strength, hardness and tackiness, are described. Special attention is drawn to the great effect that traces of oxygen, so slight that they cannot be shown analytically, may have because of the highly polymerized structure of rubber. Working hypotheses are established to explain the effect of the external factors mentioned, and these hypotheses are tested against extensive observation material. One of the most important conclusions is that it must probably be assumed that net-formed (chiefly cyclized) aggregates are present in unvulcanized rubber instead of, or in addition to, ehain molecules (Figure 3). How this affects the value of the method of determining molecular weight from viscosity measurements is discussed, and it is suggested that Kuhn's viscosity formula (4), probably with modification of the value of the exponent, will have to be applied instead of the Staudinger formula (1). It is also attempted to explain the drop in tensile strength to about 50 kg. per sq. cm. (see Figure 6) which occurs after optimum vulcanization is exceeded. It is attempted to place the responsibility for this on the oxidation which takes place during vulcanization. But it is shown by calculation that the conditions for this are in all probability not fulfilled. The rate of oxidation is high enough to reduce the tensile strength to 50 kg. per sq. cm. during normal curing conditions, but the amount of oxygen required for this purpose, about 1.5 per cent, is probably not present in rubber in a suitable form. A conclusive explanation of this decrease in tensile cannot as yet be given.