bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Study of Mechanical and Optical Properties of an Alternating NBR and an Emulsion NBR
Authors: Mukherjee U. P. , Goldstein C. 
Published: February 2011

Abstract
At low elongation, over the range of temperatures and frequencies studied, the dynamic properties (elastic modulus and loss factor) and activation energy for the glass-rubber transition are the same for highly alternating and emulsion copolymers of acrylonitrile and butadiene. At higher elongation the stress-birefringence and x-ray data on cured (1.7 phr dicumyl peroxide) highly alternating copolymer show the occurrence of strain-induced crystallization, whereas the emulsion copolymer does not crystallize under strain. The stress-strain data for the highly alternating copolymer cured at 1.7 phr dicumyl peroxide and for the emulsion copolymer cured at 1.7 phr and 0.8 phr show that at 1.7 phr dicumyl peroxide the highly alternating copolymer has higher ultimate strength. However, the emulsion copolymer cured by 0.8 phr dicumyl peroxide shows tensile properties similar to those of the highly alternating copolymer cured by 1.7 phr dicumyl peroxide. Therefore, it may be concluded that the increased strength and ultimate elongation of highly alternating copolymer, as reported by Furukawa, are due to the fact that at the same curative level the emulsion copolymer gets over-cured resulting in lower ultimate strength and elongation. This present study indicates that it is not appropriate to compare the ultimate properties of the emulsion and highly alternating copolymers cured at the same level of dicumyl peroxide. Slight adjustment in curing condition brings highly alternating and emulsion copolymers closer in tensile strength and ultimate elongation. In conclusion, it may be said that this study indicates that highly alternating NBR shows tensile properties similar to those obtained for emulsion NBR already produced commercially.
Stress-Strain Isotherms and Stress-Temperature Coefficients of Poly(Dimethylsiloxane) Networks in Compression
Authors: Chen R. Y. S. , Yu C. U. , Mark J. E. 
Published: February 2011

Abstract
Stress-strain isotherms at 30, 45, 60, 75, and 90°C have been determined for compressed, unswollen poly(dimethylsiloxane) networks which had been prepared either in the undiluted state or in solution. For these networks in compression, deviations of the dependence of stress on strain from that predicted by the statistical theory of rubberlike elasticity are much less than is the case for polymer networks in elongation. The present data nonetheless give a value for the temperature coefficient of the unperturbed dimensions of the network chains which is in good agreement with published results on networks of poly(dimethylsiloxane) in elongation. This agreement thus seems to validate the intentional disregard of such deviations in analyses of stress-temperature measurements.
Evaluation of the Theories of Rubberlike Elasticity Using Swollen Networks Crosslinked at Different Degrees of Dilution
Authors: Yu C. U. , Mark J. E. 
Published: February 2011

Abstract
A recently reported study described the preparation of elastomeric networks by crosslinking poly(dimethylsiloxane) chains in both the undiluted state and in solution. Measurements of the moduli of these networks in the unswollen state gave results supporting the theory of rubberlike elasticity developed by Flory and coworkers, rather than the corresponding theory due to James and Guth. These results were not entirely unambiguous, however, because of complications due to departures (“2C2 corrections”) from the expected elastic equation of state. Much of this uncertainty has now been removed by measurements of the moduli of such networks in the swollen state, a condition under which the effects of the 2C2 contributions are known to be minimized. These new results strongly support the earlier conclusion that the Flory theory is the more nearly correct. Nonequilibrium effects, as well as the 2C2 corrections, diminish upon incorporation of a diluent into the crosslinked network; similar decreases occur if diluent had been present during the crosslinking process, even if such diluent is removed prior to the stress-strain measurements. Analysis of these additional results suggests that the 2C2 correction cannot be entirely due to nonequilibrium effects.
Model Polystyrene Networks
Authors: Allen G. , Holmes P. A. , Walsh D. J. 
Published: February 2011

Abstract
Model polystyrene networks have been prepared, at different concentrations in an inert solvent, in such a way that the number of crosslinks is accurately known, and the topology of the network can be varied in a controlled way. The contribution of various network defects to the modulus of the network has been examined. A theoretical estimate of their effect has been made and compared to the experimental result. Two tentative conclusions have been made; first, that the front factor A in the equation for the free energy of deformation of the network has a value of 1/2 and not the alternative value 1; and secondly that the contribution of entanglements to the modulus of the network varies as the concentration squared rather than as the concentration to the first power.
A Study of Compatible Polymer Mixtures
Authors: Kwei T. K. , Nishi T. , Roberts R. F. 
Published: February 2011

Abstract
The compatibility of various compositions of polystyrene (PS)-poly (vinyl methyl ether) (PVME) films and the thermally induced phase separation of such mixtures have been studied using several methods. Density measurements indicate extensive mixing of the PS and PVME chains in compatible PS-PVME films. Vapor sorption measurements have enabled calculation of the PS-PVME interaction parameter X′23 as a function of composition and temperature. The parameter X′23 is negative for compatible PS-PVME films in the composition range 35-65 wt % PVME satisfying the thermodynamic criterion for stability in a binary mixture. The temperature dependence of X′23 for the PS-PVME system suggests the existence of a lower critical solution temperature and an upper critical solution temperature. Vapor sorption measurements also indicate that the diffusion of benzene into a 45.3:54.7 PVME-PS film is Fickian, supporting the notion of extensive mixing of PS and PVME chains in the compatible mixture. Temperature-dependent measurements of spin-lattice relaxation time T1 component, spin-spin relaxation time T2, and fraction of long T2 component by pulsed NMR indicate that compatible PS-PVME films can be described as microheterogeneous, in which PVME and PS chains, although being extensively mixed, are not completely mixed on the segmental scale. This is to be expected based on excluded volume and geometrical considerations.
Effect of Carbon Black on Poisson's Ratio of Elastomers
Authors: Holownia B. P. 
Published: February 2011

Abstract
The experimental method developed is mostly suitable for measuring K of relatively incompressible materials such as members of the elastomer family. The accuracy of K values are estimated to be within ±3% for all rubber specimens. Its use can be extended to plastics with somewhat reduced accuracy. The results show that bulk modulus K for the four different rubbers tested increases almost linearly with carbon black content while the Young's modulus E increases much more rapidly as shown in Figure 3. It is interesting to note that Poisson's ratio v calculated using K and E does not fall below 0.4940 (Figure 5), and the value of v=0.4997 as quoted in engineering handbooks would be reasonable to use for most practical applications where the carbon black content is not excessive.
Degradation of Vulcanizates and Their Identification by IR Spectrometry
Authors: Gross D. 
Published: February 2011

Abstract
Three methods have been discussed which have been successfully used for the degradation of vulcanizates for infrared analysis: pyrolysis between 450 and 600°C, degradation in 1,2-dichlorobenzene, and incomplete degradation at 200°C. Because of the relatively low cost, pyrolysis is generally used for the identification of single elastomers, but this method is less suited to blends where it may lead to the loss of ir bands characteristic of a certain component, e.g. polybutadiene. It is similarly unsuited when polymers which form mostly gaseous components are present in small amounts. Since it cannot be excluded in the analysis of vulcanizates of unknown composition, it is recommended to confirm the identification by partial decomposition at 200°C. Because of its greater cost, degradation in 1,2-dichlorobenzene is preferred only for vulcanizates containing small proportions of thermally stable rubbers. When one operates in this way, it is safe to assume that no polymer components will be missed which constitute more than 20 wt % of a rubber blend. Below this limit, identification depends greatly on the components of the blend.
Free Radicals Generated in Rubber during Fracture
Authors: DeVries K. L. 
Published: February 2011

Abstract
EPR has been used to measure molecular phenomena during fracture of elastomers. To date, because of various technical limitations, the studies have been largely confined to identification of the polymer chain scission site during fracture at low temperature in rubbers, to studying ozone-stress-induced cracking of rubber, to development of a micro-macro Griffith-type failure criteria for this type of failure, and lastly to systematic investigation of the role of filler-matrix interaction in fracture of filled elastomers. It is hoped that the brief outline presented here will give the reader some insight into the uses and potential of the EPR methods for the study of fracture. As a final note, while we have concentrated almost totally on EPR fracture studies in rubbers, there has been fairly extensive EPR work on fracture in oriented plastic, fibers, and films. Even though some of this knowledge may be transferable, directly or indirectly, to elastomers, it has not been reviewed here, but important aspects of these studies have been reviewed elsewhere.
Processing Conditions in the Batch-Operated Internal Mixer
Authors: Palmgren H. 
Published: February 2011

Abstract
This review represents an attempt to summarize and discuss some of the literature on the batch operated internal rubber mixer, with the primary view of studying processing conditions and how they influence efficiency and productivity of the process. The scope does not include materials to be mixed, their physical state, order of loading the mixer, compounding principles, systems layout, machine design, automation, mechanization, labor utilization, or other aspects of the mixing process. The discussion is limited to mixing and processing conditions connected with typical compounds, normally based on general-purpose rubbers, which today comprise by far the largest share of rubber batches mixed. It is assumed that the reader is acquainted with the mixing process and with rubber technology in general. The principal elements of the internal rubber mixer are sketched in Figure 1. Some scattered and not very coherent data on important makes of rubber mixers are collected in Tables II, III and IV and referred to in the following discussions. Since the different machines may have different applications, caution should be used in making intercomparisons. It is hoped that this review will contribute to the understanding of the mixing process, and its efficient utilization. A list of problem areas is presented at the end with the hope of stimulating future research.
Study on Bound Rubber in Silicone Rubber Filled with Modified Ultrafine Mineral Powder
Authors: Wu Jihuai , Shen Zhen , Hu Donghong , Huang Jinling , Chen Naisheng 
Published: February 2011

Abstract
The bound rubber measurement method was improved by ethylenediamine (NH2-CH2-CH2-NH2) replacing ammonia (NH3) as the basic agent. Using the new method, the influence of organic base on bound rubber content was investigated, the relation between bound rubber content and the mechanical properties of the silicone rubber filled with modified ultrafine mineral powder was studied, and the interaction between silicone rubber matrix and mineral filler was discussed. As a result, it is suggested that chemical interaction plays the main role in the bound rubber of silicone filled with modified ultrafine mineral powder.
Carbon—Silica Dual Phase Filler: Part V. Nano-Morphology
Authors: Murphy Lawrence J. , Wang Meng-Jiao , Mahmud Khaled 
Published: February 2011

Abstract
This paper demonstrates that the carbon—silica dual phase fillers are comprised of aggregates containing both carbon and silica phases. The silica is shown to be finely distributed among the carbon phases within the aggregates and within the particles of the dual phase aggregates. Analysis of the silicon content and pore volumes before and after treatment with hydrofluoric acid indicates that the silica is incorporated into the particle matrix, rather than exclusively at the surface. The silica domains are estimated to have dimensions similar to the dimensions of the carbon crystallites.
Crystallization Behavior and Strength of Natural Rubber Isolated from Different Hevea Clone
Authors: Kawahara Seiichi , Isono Yoshinobu , Kakubo Takashi , Tanaka Yasuyuki , Aik-Hwee Eng 
Published: February 2011

Abstract
Crystallization behavior of natural rubbers of different clonal origins, i.e., RRIM 600, 60/2, 2025, 2026, and skim rubbers, was investigated by dilatometry at −25 °C. The latex samples were deproteinized with a proteolytic enzyme in the presence of surfactant. Skim rubbers were purified by centrifugation followed by acetone-extraction. The over-all crystallization rate of acetone-extracted rubbers could be divided into two categories: one includes RRIM 600, 60/2 and 2025, and the other RRIM 2026 and skim rubbers. This is attributed to the differences in the level of linked fatty acid groups and gel contents. The minimum level of linked fatty acid ester groups required to promote crystallization of natural rubber is about 2.8 mmol/kg. The green strength of the rubbers is dependent on the level of linked fatty acid ester groups.
High Strain Hysteresis Loss of Rubber Vulcanizates under Pure Shear and Constrained Extension and Influence of Filler
Authors: Kar Kamal K. , Bhowmick Anil K. 
Published: February 2011

Abstract
An experimental analysis of hysteresis loss, hysteresis loss ratio and input energy of natural rubber (NR) and styrene-butadiene rubber (SBR) vulcanizates having variations of loading of carbon black, precipitated silica and clay has been carried out under uniaxial, pure shear and constrained extension modes over a range of extension ratios (1.0 to 2.2 and 1.2 to 4.0 in X and Y directions, respectively), number of cycles (1 to 8) and temperatures (25 to 125 °C). Hysteresis loss, hysteresis loss ratio and input energy increase with an increase in filler loading, extension ratio (in both directions) and reinforcement. These parameters decrease with an increase of temperature and number of stretch cycle. Hysteresis loss, loss ratio and input energy under constrained extension are higher than those under pure shear and uniaxial modes. NR and SBR vulcanizates show similar behavior. Universal expressions relating energy input at any extension ratio, W1, to the hysteresis loss (Hy) as well as hysteresis loss ratio (Hy)r under uniaxial, pure shear and constrained extensions have been developed.
Studies of Peroxide Curing of Polybutadiene/Zinc Diacrylate Blends by Fast FT-IR Imaging
Authors: Oh Sung Joon , Koenig Jack L. 
Published: February 2011

Abstract
Fast Fourier transform infrared (FT-IR) imaging measurements of cured polybutadiene(PBD)/zinc diacrylate(ZDA) showed a heterogeneous distribution of zinc diacrylate. The phase structures were classified as PBD-rich and ZDA-rich domains. Upon curing, the increase in the infrared aliphatic CH stretching mode at 2916 cm−1 and the decrease in unsaturated CH stretching mode at 3075 cm−1 were observed as the single bond crosslinks were formed at the expense of double bonds. In a solvent diffusion experiment with toluene of these cured blends, it was observed that more solvent is imbibed into the PBD-rich matrix than the ZDA-rich domains. The difference is due to the lower swelling ratio of ZDA-rich domains than that of PBD-rich matrix.
Production of Soluble Protein Free Latex by Radiation Process
Authors: Varghese Siby , Katsumura Yosuke , Makuuchi Keizo , Yoshii Fumio 
Published: February 2011

Abstract
During irradiation of natural rubber (NR) latex for vulcanization, the latex proteins undergo disintegration which leaves a high soluble protein content in latex products. In order to follow up the effects of radiation on NR proteins, field latex was irradiated with γ-rays and the soluble protein concentration in the rubber phase and serum phase were analyzed. It was found that the water solubility of proteins in the latex increases with increasing dose. The soluble protein content in the cream phase (rubber) decreased where as that in the serum phase increased with radiation dose. SDS-PAGE analysis revealed that the 27 kD protein together with 14 kD appear in the radiation vulcanized latex up to a radiation dose of 160 kGy and at 320 kGy they disappear due to the disintegration by radiation. A new process for the preparation of protein free latex has been developed. In the new process the radiation-prevulcanized, centrifuged latex is subjected to dilution and then centrifuged. In the case of field latex, it is irradiated first and then centrifuged after dilution. The new process results in prevulcanized latex almost free from soluble proteins. Tensile strength of samples produced by the new process is comparable to that from the conventional radiation process.
Frictional Sliding on a Constrained Rubber Layer: A Simple Model for a Class of Damping Devices
Authors: Li C. G. , Steif P. S. 
Published: February 2011

Abstract
Resistance to the steady sliding of a cylinder over a thin rubber layer is studied theoretically. This problem underlies a model being developed for a new class of damping devices. A quantitatively accurate model requires an accounting for the amplitude-dependent dynamic moduli of industrial-grade rubbers filled with carbon black. This accounting is hindered, however, by the lack of a full multiaxial constitutive law reflecting the nonlinear, amplitude-dependent behavior of filled rubbers. Accordingly, this paper sets forth approximate methods of analysis which indirectly account for the nonlinear behavior; these ultimately lead to compact solutions which can be used in the design of new devices.
Surface Activity and Chemistry of Thermal Carbon Blacks
Authors: Darmstadt H. , Cao N-Z. , Pantea D. M. , Roy C. , Sümmchen L. , Roland U. , Donnet J-B. , Wang T. K. , Peng C. H. , Donnelly P. J. 
Published: February 2011

Abstract
The surface energy of thermal and furnace carbon blacks was determined by inverse gas chromatography (IGC) at infinite dilution. In general, the specific surface energy decreases with decreasing carbon black specific surface area. However, there is also an influence of the concentration of impurities during the carbon black production. The surface energy decreases with decreasing concentration of impurities. The carbon black surface and bulk chemistry was studied by electron spectroscopy for chemical analysis (ESCA), secondary ion mass spectroscopy (SIMS) and Raman spectroscopy. Scanning tunnelling microscopy (STM) was used for characterization of the surface morphology. Thermal grades of carbon black produced from high purity natural gas feedstock do not contain fewer surface functional groups than the other grades. No correlation between the concentration and nature of the oxygen and sulphur surface groups and the carbon black surface energy was found. Instead, a correlation between the surface energy and the polyaromatic character of the carbon black surface exists. Both increased in the order: thermal blacks from high purity natural gas feedstock &lt; thermal black from oil feedstock &lt; furnace blacks. The increase of the surface energy might be related to the formation of active sites which are formed upon removal of non-carbon elements during the carbon black formation. There was no principal difference in the surface morphology of thermal blacks from high purity gas feedstock and other blacks.
Direct Comparison of Some Recent Rubber Elasticity Models
Authors: Seibert D. J. , Schöche N. 
Published: February 2011

Abstract
The paper compares the Arruda—Boyce model, the van der Waals model and the Reduced Polynomial model—a generic class of polynomial models of which Yeoh's cubic model is a special case—in their ability to predict multiaxial deformation states on the basis of uniaxial measurements. These models are reviewed in the light of novel experimental data, giving ample space to the derivation of the equations needed for optimization of the material parameters. The technological relevance of these findings is exemplified in the finite element analysis (FEA) of a complex membrane.
Constitutive Models of Rubber Elasticity: A Review
Authors: Boyce Mary C. , Arruda Ellen M. 
Published: February 2011

Abstract
A review of constitutive models for the finite deformation response of rubbery materials is given. Several recent and classic statistical mechanics and continuum mechanics models of incompressible rubber elasticity are discussed and compared to experimental data. A hybrid of the Flory—Erman model for low stretch deformation and the Arruda—Boyce model for large stretch deformation is shown to give an accurate, predictive description of Treloar's classical data over the entire stretch range for all deformation states. The modeling of compressibility is also addressed.
Reinforcement of Rubber
Authors: Hamed Gary R. 
Published: February 2011

Abstract
One of the most important phenomenon in material science is the reinforcement of rubber by rigid entities, such as dispersed particulate filler or phase-separated organic domains. In order to impart significant reinforcement, the size of the hard phase must be small, much less than a micron. The basis of this requirement is a major focus of this short review. Furthermore, the roles of energy dissipation and crack deflection in rubber reinforcement are considered. The final part of the review deals with nano-composite rubbers, in which rigid domain size is in the range of 1–10 nm.
Characterization of Silica Xerogels Surfaces by Inverse Gas Chromatography (IGC)
Authors: Donnet J. B. , Wang T. K. , Li Y. J. , Balard H. , Burns G. T. 
Published: February 2011

Abstract
Silylated silica xerogels, with controlled specific surface area and porosity, were prepared by a two-step procedure. In the first step, hydrogels were treated “in-situ” with hexamethyldisiloxane (HMDS) in the presence of 2-propanol and acid. In the second step, the hydrophobic gel was transferred into an organic solvent, the residual water removed by azeotropic distillation and the dried xerogel isolated by evaporating the solvent. Using this procedure, structure collapse of the hydrogels was minimized and it was possible to make xerogels with controlled specific surface area and porosity by varying the aging conditions of the hydrogels. The surface properties of both the untreated and the “in-situ” treated silica xerogels were examined by inverse gas chromatography (IGC) at either infinite dilution conditions (IGC-ID) or finite concentration conditions (IGC-FD). The former method was used to monitor the thermodynamic parameters of adsorption of molecular probes in interaction with the sites having the highest energies, while the latter method was used to provide information about the surface energy heterogeneity of the whole surface. The results for the xerogels are also compared to those obtained on untreated and silylated fumed silicas. After silylation, a systematical surface energy decrease has been observed at both ID and FD conditions of IGC for the two types of silica. However, the modified xerogels with higher surface coverage than silylated fumed silica show some different behaviors.