bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wool graft copolymers initiated by azobisisobutyronitrile
Authors: Bendak A. , Hebeish A. 
Published: April 2003

AbstractGrafting of methyl methacrylate onto wool fibers using azobisisobutyronitrile as initiator has been investigated under a variety of conditions. Increasing the monomer concentration caused a significant increase in the graft yields. The same holds good for initiator concentration and reaction time, but to a lower degree. The grafting reaction was favorably influenced considerably by the nature of solvent used; it follows the order methanol > dimethylformamide > benzene. For practical significance, a mixture of water:methanol:DMF (75:24:1) was found to be the most effective medium for grafting. Presence of lithium chloride in the polymerization system favors grafting during the later stages of reaction, whereas presence of ceric sulfate was effective for higher grafting in the initial stages of reaction. Reduction of wool prior to grafting enhanced its ability to grafting; the latter increases in proportion to the thiol content. The opposite holds true for acetylation. Alkali solubility measurements reveal that an interaction between wool and methyl methacrylate in presence of AIBN took place.
Investigation of the dependence of the properties of the phenoplasts of phenolaniline–formaldehyde resol resin on the degree of kaolin filling and on their physical structure
Authors: Bozveliev L. G. , Kabaivanov V. S. 
Published: April 2003

AbstractAn investigation was made of the dependence of 13 types of standard physical and mechanical and electric insulation properties of phenoplasts of phenolaniline–formaldehyde resol resin on their filler content in a broad range of 14 to 47 vol‐%. It is found that the respective curves have more than one maximum and periodically pass through several maximums and minimums. The periodicity is more clearly seen in the curves reflecting the dependences of the properties on the calculated mean thickness of the resin adsorption coating on the filler particles. With these curves the extremal values appear over more or less even intervals of the adsorption coating thickness. The periodicity relating to the change in this thickness is explained by the periodic formation of particles of a new type of filler in the points of a whole number of monoglobular adsorption coatings, and of a maximum amount of globules oriented toward them in the points of a whole number and a half monoglobular adsorption layer. The periodical appearance of an oriented (regarding the particles) globular layer determines the appearance of periodical positive and negative orientation effects in the properties of the phenoplasts. The diagram we propose is confirmed by the regular periodical change in the various properties as well as by the measured ratios of the mean thicknesses of the adsorption coating in the points of the extremums of the various types of curves, determined by the differential curves method.
The market for polyester, nylon, and rayon yarns in tire applications
Authors: Promislow A. L. , Steele R. , Whitworth P. D. 
Published: April 2003

AbstractThe use of rayon, nylon, and polyester in various tire applications is described, and the relative merits of each are defined. Future development objectives and expectations are outlined. Volume projections for polyester, nylon, and rayon in tire reinforcement are given as a function of tire type. Product life cycles of tire reinforcement materials are analyzed in terms of market share. Polyester is expected to become dominant in 1973.
Fiber properties required for tires
Authors: Snyder Robert H. 
Published: April 2003

AbstractContrary to what the appearances would suggest, a pneumatic tire is basically an engineered textile object rather than a rubber one. The functional characteristics and performance of tires are chiefly determined by the properties of the textile fibers and by the way in which they are disposed in the tire structure. The specific roles of some of these properties (e.g., modulus, tensile strength, fatigue resistance, hysteresis) will be related to tire performance. Different tire constructions require a different balance of textile properties for optimum performance. Belted tires, and especially radial ply tires, present a different set of requirements for optimum textile fiber performance in tires. The nature of the differences are discussed.
Fiber glass—its future in belted tires
Authors: Kerivan Alan R. 
Published: April 2003

AbstractThe rapid success of fiber glass‐belted tires (from very low production in 1966 to one hundred million units in 1971) is discussed in terms of specific cord properties. The inherent glass characteristics of high modulus, high tensile strength, and low elongation are shown to be ideal for belted tires. Applications of fiber glass for belts of light commercial and heavy‐duty tires are discussed. The opportunity for developing new fiber glass cords which offer improved cost/performance characteristics are explored, including cord geometry and fiber diameter. The cost/performance capabilities of fiber glass for use in radial tires, both in the belt and in the carcass, are discussed as additional future opportunities. Laboratory and road test information is detailed and outlined. Ride aesthetics of the all‐glass radial tire design is emphasized. The market penetration for fiber glass tire cord will be projected through 1980.
Current inorganic fibers for tires: Steel
Authors: De Bruyne E. A. , Vanhoutte J. S. 
Published: April 2003

AbstractAn outline covering the evolution of the more popular tire‐reinforcing materials from 1960 to 1970 is presented. Technical and economic factors pro/con steel tire cord for that period are reviewed. Using the past period as a base, the present and future prospects for steel tire cord are analyzed. Comments on the present properties of steel tire cord in relationship to tire requirements are given. In addition, desirable and expected product improvements are covered with special emphasis on achievable product development.
Future organic tire fibers
Authors: Wilfong Robert E. , Zimmerman Joseph 
Published: April 2003

AbstractIn the history of the automobile, organic fibers have dominated the tire reinforcement field, starting with cotton and progressing through a series of man‐made fibers, each finding its place on the basis of its special attributes and overall performance. In general, these fibers were engineered for textile applications, but were subsequently adapted by special processing to make them as suitable for tires as possible. However, each has had limitations which have kept it from certain segments of the market. Moreover, the performance demands on tires have become progressively more stringent, and new tire designs have evolved, so that new tire reinforcement materials are needed. While glass and steel wire are contributing some of the desired properties, they also have their limitations. On the other hand, the potential for creating new, more favorable property balances from organic fibers is far from exhausted. This paper will discuss the main tire yarn property criteria and the polymer and fiber structural factors which control them. Then, the properties and performance of an entirely new fiber, specifically engineered chemically and physically for tire reinforcement, will be described. Fiber properties discussed will include tensile strength, modulus, dimensional stability, fatigue resistance, adhesion, and thermal stability.
Fracture studies in rubber‐modified polymers. II. Experimental results: Fracture surface work of rubber‐modified acrylics
Authors: Kobayashi T. , Broutman L. J. 
Published: April 2003

AbstractWith the use of a sandwich‐tapered double‐cantilever beam cleavage specimen (described in part I of this series), the fracture surface work of several commercial and experimental acrylic multipolymers has been measured as a function of crack velocity and rubber content. The plots of fracture surface work versus crack velocity clearly exhibit the effects of rate (crack velocity) and rubber concentration on fracture behavior. Specifically, the fracture surface work of specimens with seven different rubber contents has been determined over a crack velocity range from 10−5 meters/sec to approximately 10 meters/sec. For each material, distinct maxima occur in the curves of fracture surface work versus crack velocity. The significance of these observations is discussed.
Thermomechanical behavior of a systematic series of poly(L‐alpha‐alkylamino acids) in dry and moist nitrogen
Authors: Krug R. R. , Gillham J. K. 
Published: April 2003

AbstractThe solid‐state thermomechanical behavior of polyglycine, poly‐L‐alanine, poly‐L‐valine, and poly‐L‐leucine was investigated throughout the temperature range −180° to 500°C in dry and moist nitrogen atmospheres at about 1 cps using torsional braid analysis. Transitions of the dry polymers and complexities introduced by the presence of water were investigated by temperature cycling.
Gel permeation chromatography: Differential operation
Authors: Chuang Jau‐Yi , Johnson Julian F. 
Published: April 2003

AbstractOperation of gel permeation chromatographs in the differential mode provides a sensitive method for detecting small differences in molecular weight distribution between similar samples. The solvent used in this case is a dilute solution of the reference polymer in an organic solvent. This solution is used in both the reference and the separation column. Samples of the material to be compared are injected in the normal manner. Only differences between the samples are reflected in the resulting chromatogram. For process control, this offers a simplified data presentation and should lead to easier detection of changes in operating conditions.
High‐temperature elastomers: A systematic series of linear poly(carborane‐siloxane)s containing icosahedral (CB10H10C) cages. I. Thermomechanical behavior in nitrogen
Authors: Roller M. B. , Gillham J. K. 
Published: April 2003

AbstractAn extensive study of structure–bulk property relations for a systematic series of well‐defined linear poly(carborane‐siloxane)s is reported. These polymers form the backbone components of the most recently developed high‐temperature elastomers. The basic structure is
magnified image
where (1) x = 1, 3, 4, 5, ∞; (2) A = endgroups (reactive and inert); (3) Z = meta‐, para‐carborane (for x = 3); (4) R = CH3, R = C2H4CF3 (for x = 3), one in five R = C6H5 with the remainder ∼CH3 (for x = 4, randomly and regularly substituted); (5) molecular weight = ∼10,000, ∼50,000 (for x = 3). Thermomechanical spectra (∼1 cps) from −180°C to 625°C to −180°C in nitrogen at 3.6°C/min and thermogravimetric data from 25°C to 800°C in argon are presented. Physical transitions (Tg, Tm, Tcrys, Tsec) are discussed, including a correlation of Tg data with structure (for x = 1, 2, 3, 4, 5, ∞) using a copolymer equation. Thermostability is also discussed in terms of structure.
Low‐angle x‐ray scattering investigation of untreated and alkali‐treated jute
Authors: Sahu N. C. , Mishra D. 
Published: April 2003

AbstractPore analysis of untreated and alkali‐treated samples of jute by the low‐angle x‐ray scattering method was made. The measurements were made using the low‐angle scattering camera of the latest design by Kratky.1 The theories of Kratky2–4 and Porod5–7 were used to evaluate and compare the various parameters of the scattering particles present in both types of jute fibers. Babinet's8 reciprocal principle of scattering in optics was taken into account.
Mechanism of yield and fracture in ABS materials
Authors: Hagerman Edward M. 
Published: April 2003

AbstractFour commercial grades of ABS of varying physicomechanical properties were fractured in tension at three straining rates. Photomicrographs of the fracture surfaces were used to qualitatively describe the effects of straining rate on craze growth. Based on a micrograph of what is assumed to be the first stress‐activated state of craze formation, a model describing the function of the elastomer phase in these materials is presented.
A method for determining the optimum peroxide‐to‐amine ratio for self‐curing resins
Authors: Bowen R. L. , Argentar H. 
Published: April 2003

AbstractThe rate of polymerization of a methacrylate monomer was influenced by the molar ratio of benzoyl peroxide to an aromatic tertiary amine accelerator when the product of the concentrations of these was kept constant. The maximum rate, measured as the minimum gel time, occurred in monomer solutions containing about 1.5 moles of peroxide per mole of amine.
Polyesters from bisacid A2. Electrical properties of glass fiber laminates
Authors: Lenk R. S. 
Published: April 2003

AbstractThe preparation and purification of bisacid A2, the preparation of crosslinkable polyesters from bisacid A2, and some of the properties of the resulting resins and laminates have been reported in earlier communications.1–7 This paper reports the surface and volume resistivities of laminates according to B.S. 2782 as well as their dielectric loss and permittivity at 23°C over a frequency range of about 9 decades and discusses the significance of the results.
Water binding and irreversible dehydration processes in cellulose acetate membranes
Authors: Frommer Moshe A. , Shporer Mordechai , Messalem Rami M. 
Published: April 2003

AbstractThe relative amounts of freezing and nonfreezing water in various water‐wet cellulose acetate (CA) membranes were determined by NMR techniques, from the initial heights of the water component in the free induction decay (MNR intensity). The results suggest that (1) a significant fraction of the water in various wet CA membranes does not freeze, probably because of strong interaction with the polymer; (2) the relaxation times T2 of the nonfreezing water are of the order of milliseconds indicating that they are still highly mobile compared with ice; (3) all the water contained in dense CA films or in membranes equilibrated at relative humidity of 0.93 does not freeze upon cooling the membranes from room temperature to −60°C; (4) the amounts of nonfreezing bound water in membranes is higher than the total amount of water absorbed from liquid water by a dense film of the same polymer. However, the amounts of nonfreezing water in various CA membranes as calculated from the “relative NMR intensities” is substantially lower than those calculated from DSC melting endotherms by assuming the heat of fusion of water in membranes to be identical to that of pure water. Various possible reasons for this discrepancy are discussed. Measurements on the first desorption‐adsorption cycle of wet CA membranes have also been performed. They suggest that during the first dehydration process, irreversible changes are induced in the structure of the membrane which result in a significantly lower accessibility of the polymer to interact with water. The extent of these irreversible changes in membrane structure is dependent on the details of the dehydration process being more pronounced at higher temperatures.
Preparation of the fine powdery copolymer of glycidyl methacrylate–divinylbenzene and its application as a pigment
Authors: Mizutani Yukio , Matsuoka Seishiro , Kusumoto Koshi 
Published: April 2003

AbstractIn order to prepare the functional and fine powdery polymer, glycidyl methacrylate (GMA) and divinylbenzene (DVB) were polymerized in cyclohexane. This polymerization was heterogeneous. In the time–conversion curve, an autoaccelerating phenomenon and an apparently steady state were observed, and the activation energies for both reactions in the earlier stage and the steady state were calculated to be 28 kcal/mole and 11 kcal/mole, respectively. It is especially noteworthy that the increase in the DVB concentration decreased the polymerization rate. The diffusion of the monomers through the polymer matrix should be one of the most important factors. Some properties of the copolymer and its application as a mordant were studied.
Preparation and physical properties of polybutadiene grafted onto silica
Authors: Yamashita Shinzo , Kohjiya Shinzo , Kita Atsushi , Shimizu Akihiko 
Published: April 2003

AbstractPolybutadiene grafted to silica (PG) was prepared by the reaction of living polybutadiene with chlorinated silica. The graft efficiency was below 10%. PG and PG–commercial butadiene rubber blend were cured with sulfur. In either vulcanizate, the following phenomena were found as compared with the controlled samples: tensile modulus increased, degree of swelling and elongation lowered, and tensile strength unchanged. These results showed nearly the same tendency as had been found in the case of the rubber compounded with silica which was treated by coupling agents. In spite of a high tensile modulus of PG vulcanizate, it resulted in a lowering of the dynamic modulus compared with the controlled sample.
Studies of relaxation phenomena in polymers. III. Superimposed transition mechanisms in polyisobutylene and poly(vinyl acetate)
Authors: Jansson Jan‐Fredrik 
Published: April 2003

AbstractBased on the general properties of the function log J2 = gα{log J1}, discussed in earlier papers,1,2 the existence of two superimposed dispersion mechanisms in the glass–rubber transition of polyisobutylene (PIB), and poly(vinyl acetate) (PVAc) is discussed. A simple weighting model is used for separation of the two mechanisms. For the interpretation of the β‐mechanism, in PIB, the following facts are taken into account: (a) The loss maximum of the β‐mechanism appears in a zone where only very reduced segment movements occur. (b) The methyl side groups in PIB require special conformations of the main chains before they can rotate. (c) The apparent activation energy for the β‐mechanism is approx. 20 kcal/mole. Thus, for PIB the following interpretations for the α‐ and β‐mechanisms are proposed: (1) The α‐mechanism is due to simple segment movements. (2) The β‐mechanism appearing in the “Tg region” is due to coupled movements between the main chain and methyl side groups. The ester groups of poly(vinyl acetate) need a lot more space for their rotations than the carboxy groups of poly(methyl acrylate) and can be expected to give considerable steric hindrance. It is therefore reasonable to suppose that a transition mechanism similar to the β‐mechanism of polymethacrylates will appear in the “freezing” region of poly(vinyl acetate). The analysis of the β‐mechanism is made using the same separation method as for polyisobutylene.
Prediction of molecular weight distribution of high‐density polyethylene made in a continuous reactor from fixed ethylene concentration batch reactor data
Authors: Hoff R. E. , Shida M. 
Published: April 2003

AbstractThe polydispersity index, Mw/Mn, of the product of an ideal continuous stirred tank reactor can be predicted from batch reactor data. A method for the prediction, in the case of high‐density polyethylene synthesis, comes from finding the effect of catalyst age upon yield, Mw, and Mn in a batch reactor operated at constant pressure. These catalyst age effects are combined with the catalyst age distribution in the continuous reactor, and integration over all ages gives the yield and the polydispersity index for the continuous reactor product. This scheme for prediction was applied to a particular catalyst system, and the calculated values have been found to agree with observations.
1‐Chloro‐1,3‐butadiene copolymers. I. Synthesis of copolymer with 1,3‐butadiene and physical properties of its vulcanizate
Authors: Yamashita Shinzo , Atomori Sei‐Ichi , Kohjiya Shinzo , Miyagawa Toshio 
Published: April 2003

AbstractEmulsion copolymerization of 1‐chloro‐1,3‐butadiene and 1,3‐butadiene was carried out using potassium persulfate at 50°C. The thus synthesized 1‐chloro‐1,3‐butadiene copolymer was possible to be cured with 2‐mercaptoimidazoline (MI) as well as with sulfur. The tensile strength of the MI vulcanizate of the copolymer compounded with 30 phr HAF black reached 100 kg/cm2 and was higher than that of the sulfur vulcanizate. Moreover, these two vulcanizates showed higher tensile strengths than the sulfur vulcanizate of emulsion butadiene rubber. The addition of the copolymer to the blend of chloroprene rubber (Neoprene GRT) and butadiene rubber extremely improved the elongation and the tensile strength. Dynamic measurements of the vulcanizates showed that the glass transition temperature of the copolymer was situated at the region between that of butadiene rubber and that of chloroprene rubber.
Determination of optimal reactor system configuration for polymerization reactions. I. Free‐radical polymerization at constant temperature
Authors: Shastry J. S. , Fan L. T. , Erickson L. E. 
Published: April 2003

AbstractA systematic procedure was developed for selecting the type of reactors or a reactor system configuration for polymerization reactions. Two different mechanisms were investigated, and the “best” reactor system to give the desired quality of the product was determined using a systems synthesis technique. The behavior of the system in the neighborhood of the optimal solution was explored, and the effect of variation in the rate constants and the initial concentrations of the catalyst and the monomer on the optimal reactor system was examined. Recycle streams were introduced and their effect on the system performance was investigated, and finally the applicability of the systems synthesis technique to other polymer reactor design problems was discussed.
Thermal behavior of nylon 6 copolyamides containing aromatic rings
Authors: Ajroldi G. , Stea G. , Mattiussi A. , Fumagalli M. 
Published: April 2003

AbstractThe thermal behavior of terpolymers of caprolactam (CL) and of hexamethylenediammonium isophthalate (IH) and terephthalate (TH) has been studied in a wide range of compositions by differential thermal analysis. It has been found that either amorphous or crystalline polymers having different crystallization rates can be obtained by changing the composition. The dependence of melting points and glass transition temperatures on the composition has been investigated. The dependence of Tg on the composition for the copolymers CL–IH, IH–TH, and CL–TH has been described by means of the Gordon‐Taylor equation. It has been found that this equation fits the experimental data for the IH–TH system only if a parameter which takes into account interactions between the monomeric units is introduced. A ternary iso‐Tg map has been obtained through statistical analysis. The influence of the chain stiffness and bulkiness of the monomers on the glass transition temperature is discussed.
Increase of gold–Teflon FEP joint strength by electron bombardment
Authors: Sessler G. M. , West J. E. , Ryan F. W. , Schonhorn H. 
Published: April 2003

AbstractThe strength of joints between Teflon FEP (Type A) and 500‐ to 1000‐Å gold layers deposited by evaporation can be greatly increased if the Teflon surface is subjected to electron‐beam bombardment prior to the evaporation process. Typically, joint strengths of about 60 kg/cm2, approaching the bulk strength of Teflon, are obtained for treatments with electron‐beam energies in the range of 5 to 20 keV and intercepted charge densities of about 5 X 10−6C/cm2. This compares with gold–Teflon joint strengths of about 10 kg/cm2for untreated material. The increase in joint strength is believed to be primarily due to crosslinking caused by the electron bombardment. Compared to the other known treatments to improve gold–Teflon joints, the present method has the advantage that the charge‐storage properties of the Teflon are not irreversibly degraded. It is possible, for example, to store charge densities up to 3 X 10−8C/cm2, on 25‐μm films treated with this method, with the same favorable charge‐retention properties and thermally stimulated current characteristics as obtained for untreated Teflon.