bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon—Silica Dual Phase Filler: Part III. ESCA and IR Characterization
Authors: Murphy Lawrence J. , Wang Meng-Jiao , Mahmud Khaled 
Published: February 2011

Abstract
A series of carbon—silica dual phase fillers have been analyzed using electron spectroscopy for chemical analysis (ESCA) and infrared spectroscopy (IR). These techniques reveal that the silicon in these materials is consistent with that in silica, and the predominant carbon in the carbon phase is similar to the predominant carbon in carbon black. ESCA and IR experiments demonstrate that the carbon—silica dual phase fillers are comprised of composite aggregates, each containing carbon and silica phases. In these dual phase aggregates the silica phase is intimately distributed with the carbon phase. Quantitative ESCA reveals that these dual phase fillers have excess oxygen over the expected stoichiometric amount for the silica present. This excess oxygen is likely due to oxygen groups on the carbon phase. Analysis of the ESCA oxygen Auger lines in combination with various chemical treatments substantiate the presence of carbon phase oxygen groups on the dual phase fillers. Quantitative ESCA in combination with IR spectra of a dual phase filler after removal of the silica phase, by HF treatment, suggests that the carbon phase of the dual phase filler contains more oxygen groups than its carbon black counterpart.
Preparation of Soluble TiCl3 Catalysts and Their Use for Copolymerization of Ethylene with Propylene
Authors: Makino Kenya , Tsuda Kazuichi , Takaki Mikio 
Published: February 2011

Abstract
The solubilization of TiCl3 catalysts in organic solvents was carried out to enhance the activity for random copolymerization of ethylene with propylene. β-TiCl3 · 1/3AlCl3 was solubilized in halogenated hydrocarbon solvents by using an appropriate ether as donor. α-TiCl3 free from AlCl3 was found to be soluble in the presence of a VCl4 or VOCl3 ligand and a suitable ether. The solubilized TiCl3 catalysts showed high catalytic activities for the copolymerization using trialkylaluminum compounds as a cocatalyst. The copolymers obtained possessed low crystallinities. Also, the copolymers seem to contain a microblock type of sequences and outstandingly high tensile strength and elongation at break compared to copolymers by conventional VCl4 and VOCl3 catalysts.
Deformation Index—Concept for Hysteretic Energy-Loss Process
Authors: Futamura Shingo 
Published: February 2011

Abstract
The concept of deformation index can be effectively used to determine the relevant dynamic viscoelastic property which best correlates with the performance of the rubbery material. The concept also indicates the type of deformation that may govern a complex energy loss process, although, in this study, the underlying physical process was not experimentally identified.
Thermal Crystallization of Polytetrahydrofuran Networks
Authors: Roland C. Michael , Buckley Gary S. 
Published: February 2011

Abstract
The formation of a network in PTHF inhibits the crystallization of chain units in proximity to the crosslinks. From melting-point-depression measurements, it is estimated that the suppression in crystallizability extends to as much as 8 chain units away from a network junction. This estimate is consistent with the degree of crystallinity measured in various crosslinked PTHF rubbers. The equilibrium melting point for linear PTHF was determined to be 361°K. Although this is significantly higher than previously reported values, the present result is congruent with the melting temperatures measured for crosslinked PTHF, and its use leads to satisfactory predictions of their melting-point depression. The distribution in the lengths of network chains exerted a trivial influence on thermal crystallization behavior. Although this distribution must in principle influence crystallization behavior in so far as it governs crystallizable sequence lengths, differences between uni- and bi-modal network architectures were moderate under the present experimental conditions.
Metathesis Polycondensation Chemistry as a Route to Unsaturated Elastomers
Authors: Wagener K. B. , Nel J. G. , Duttweiler R. P. , Hillmyer M. A. , Boncella J. M. , Konzelman J. , Smith D. W. , Puts R. , Willoughby L. 
Published: February 2011

Abstract
Acyclic diene metathesis (ADMET) polymerization offers a new opportunity to generate a wide variety of elastic structures using room temperature reaction conditions. It also offers the opportunity to modify existing elastomer structures through trans-metathesis copolymerization reactions. ADMET depolymerization could have tremendous significance if, in fact, the reaction can be applied to the recovery of commercial vulcanized elastomers. All of these opportunities are presently being investigated in our laboratory.
Adhesion between Hydrogenated Nitrile Elastomers and Fibers Is Improved Using Hydrogenated Acrylonitrile-Butadiene Latex
Authors: Kubo Yoichiro , Mori O. , Ohura K. , Hisaki H. 
Published: February 2011

Abstract
1. The hydrogenated acrylonitrile-butadiene latex (HNBR latex) was developed as a heat-resistant adhesive agent suitable for use between HNBR and fibers. 2. In the case of the adhesion of HNBR to nylon, both the initial adhesion strength and the adhesion strength after heat aging using HNBR latex is higher than those using NBR latex. 3. In the case of the adhesion of HNBR to polyester, polyester undergoes hydrolysis by the amines which originate from the accelerators in the recommended recipes. Two prevention methods against the degradation of polyester by amines were developed. a. From the balance between the adhesion strength and cured properties of HNBR, the combination system with tetraethyl thiuram disulfide (TETD) and dibenzothiazyl disulfide (MBTS) was selected as the vulcanization system for HNBR. b. As the preventive function against the penetration of amines from elastomer to polyester, the double layer adhesion system was developed in which the first treatment is given with the carboxylated vinylpyridine-butadiene-styrene latex and the second treatment is given with the HNBR latex.
The Possibility of Using Grafted Waste Rubber
Authors: Adam G. , Šebenik A. , Osredkar U. , Ranogajec F. , Veksli Z. 
Published: February 2011

Abstract
With the addition of 20 phr of BR granulate grafted with ethyl acrylate by the redox or gamma irradiation method to polyacrylic rubber compound, the properties of the rubber worsened, but remained within the range of properties characteristic for these types of rubber. The stability of rubber against swelling in hot mineral oil was satisfactory even when 30 phr of grafted granulate was added to polyacrylic rubber. It can be concluded that polybutadiene granulate when grafted with ethyl acrylate, gains some properties characteristic for polyacrylic rubber due to the introduction of polar groups into the polymeric chain of the BR rubber. This might also be the reason why polybutadiene granulate grafted with ethyl acrylate could be in no case added to polybutadiene rubber regardless of the grafting method. No attempt was made so far to evaluate the economical aspects of grafting waste rubber and the real possibility of using grafted granulate on a large scale.
Nonlinear Elastic Analysis of the Hardness Test on Rubber-Like Materials
Authors: Chang W. V. , Sun S. C. 
Published: February 2011

Abstract
Both the Ogden-Tschoegl nonlinear elastic constitutive law and a contact algorithm in the general-purpose finite-element program AFEM have been used to examine the use of IRHD values to relate the elastic properties of elastomers. We are aware that large deformations of rubber specimens and complicated interface conditions are involved in this so-called simple test. However, from the finite-element results, we find that the linearly elastic Hertz contact solution is a reasonably accurate model. This can be attributed to several points. First, the hardness test involves mainly compression and shear deformation and the linearly elastic behavior is more closely followed in rubbers for the above two types of deformation. Second, although nonlinear effects become significant in soft rubbers and higher indentation cases, the ASTM D 1415 standard defines larger indentation depth differences for smaller IRHD values. The definition itself compensates for the nonlinear effects. Third, although the interfacial stress field changed due to different frictional conditions, we calculated the IRHD values only from indentation depth difference and total load applied to the steel ball. Both the indentation depth difference and the total load are obtained from far-field conditions and do not change significantly. We should note that using linear elasticity to correlate the elastic moduli and IRHD values is simply a special case in rubber elasticity. We conveniently get rubber's elastic moduli from IRHD values based on linear elasticity, but the complete rubber-like material behavior has to be obtained from more general experiments and described by a nonlinear constitutive law such as the Ogden-Tschoegl model.
Effects of Field Storage on Guayule Rubber Quantity and Quality
Authors: Dierig D. A. , Thompson A. E. , Ray D. T. 
Published: February 2011

Abstract
Irrigation treatments affected the amount of biomass produced, but not the NR percentage of the plant or the quality or quantity. Different guayule genotypes varied in their rate of rubber degradation over storage time. All lines tested in this experiment decreased in Mw by the end of the storage period, but degradation in some did not occur until the fourth week of storage. An increase in Mw of most lines was seen after the first week of storage, indicating that the enzymatic processes are still functioning beyond the first few hours of harvest, and for some lines, beyond the initial sample taken after one week of field storage. Other lines may follow this same pattern of degradation, but it was not detected by the sampling protocol in this study. Guayule lines 11605, 11619 and interspecific hybrid AZ101, when irrigated between 4 to 7 times per year (50 to 90 cm/year), harvested in early spring, and then stored in the field as whole plants for no more than 2 weeks, would yield optimum rubber quality and quantity (per acre) with little or no deterioration. Other lines in this study, 11604, N565, 593, and 11634, cannot be field stored for longer than 1 week without a loss of rubber quality and quantity based on these results. The variation seen in the different lines indicates two important points. First, the amount of time plants remain in the field following harvest is an important determinant of rubber quality and quantity. Secondly, selection for degradation characters should be possible for crop improvement.
Analysis of the Dynamic Stress Relaxometer Test Geometry and Conversion of Relaxing-Torque Data to Frequency-Dependent Viscoelastic Properties
Authors: Harrell E. Ray , Porter John P. , Nakajima N. 
Published: February 2011

Abstract
The test geometry of the DSR has been mathematically modeled to provide an adequate description of the strain (and stress) distribution within a test specimen. The consideration of three separate deformation regions were required. Two of these regions, not considered in previous models, contribute 27% to 59% (depending upon the user-selectable closure height) of the total measured torque exerted on the DSR rotor. The utility of this model has been demonstrated by the agreement between the stress relaxation data obtained by converting the DSR relaxing torque measurements, using the modeled form factor, and data obtained with a uniform-strain-deformation instrument (RMS with cone and plate fixture) for four elastomer samples. Furthermore, the transformation of the converted DSR stress relaxation data to the frequency domain revealed good agreement with the frequency-dependent shear loss and storage moduli and complex viscosity obtained from RMS oscillatory experiments.
Effect of Carbon-Black Loading and Crosslink Density on the Heat Build-Up in Elastomers
Authors: Meinecke Eberhard 
Published: February 2011

Abstract
It has been shown that it is possible to predict the viscoelastic response of elastomers and elastomeric engineering components under both load- and position-control conditions if one assumes: a) that the modulus of the materials increases with the strain amplification factor as given by the Guth and Gold equation, b) that the occluded rubber is taken into account when using this equation, and c) that the energy loss per cycle and unit volume of material is increasing with the square of the strain-amplification factor. These calculations were applied to an assembly where one unfilled section is in series with a filled one. The overall filler loading was kept constant, and it was found that the equations derived show completely different heat-generation rates for load- and position-control conditions. While the losses are the same in both sections and equal to that of the assembly as a whole under position-control conditions, they are quite different under load-control conditions. They increase with both filler loading and values of α and abnormally high local overheating in the unfilled section occurs. These considerations indicate that a uniform mixing quality is important for compounds which will be used in dynamically deformed engineering components. Under position-control conditions, poor filler dispersion will give rise to a decrease in the dynamic modulus and the energy loss per cycle, i.e., variations in the quality of the mix will cause variability of the dynamic properties. Under load-control conditions, the situation is even worse, since the energy dissipation increases with poor mixing, and local overheating of the sections containing less than the average amount of carbon black takes place. The model is obviously too oversimplified for qualitative predictions. But it still gives good qualitative indications regarding the heat-generation rate in structures made from two elastomers having different filler loadings or for imperfectly mixed compounds.
Injection Molding of Rubber Compounds: Experimentation and Simulation
Authors: Deng J. S. , Isayev A. I. 
Published: February 2011

Abstract
Results of experimental and theoretical studies of injection molding of rubber compounds have been reported. Characterizations on the rheological properties and the vulcanization kinetics of rubber compounds were carried out by means of MPT and DSC, respectively. The models were employed to fit these experimental data. An attempt has been made in extending the proposed empirical kinetic model based on DSC data to similar curing data obtained by means of the MDR technique. The heat-transfer effect due to the large sample size used in MDR measurements has been found to have a small effect on the kinetic data. Due to the different principle of state-of-cure measurements in MDR and DSC, the model parameters of curing kinetics have been found to be different in these measurements. A two-dimensional flow simulation of generalized Newtonian fluids based on both finite-difference and finite-element methods has been performed. The pressure development at various positions along the flow path during the filling stage of the molds was obtained experimentally for various injection speeds. The predicted results on pressure development during cavity filling showed qualitative agreement with the experimental data. Possible reasons for the observed discrepancy in pressure traces are: neglect of local extra pressure losses (in the juncture sections), compressibility of rubber compounds, leakage (back-flow) of material during injection, and voids formation in the injection chamber. The study on the vulcanization behavior of rubber compounds during injection molding process has also been done. The proposed empirical kinetic and induction time models were able to satisfactorily predict the cure levels of molded rubber products. At the same time, the results predicted by employing nth order kinetics were found to be unsatisfactory. The contribution of nonisothermal induction time in calculating cure levels of the molded rubber products was found to be significant. The mechanical properties and anisotropy have been investigated for two rubber compounds. It is suggested that there exists a mold temperature at which the properties and cycle times are optimal, and the filler type shows a significant effect on the tensile modulus. The rubber moldings were found to be highly anisotropic in mechanical behaviors. The anisotropy could be reduced significantly at high injection speed due to the faster stress-relaxation process.
Polyolefin Thermoplastic Elastomer Blends
Authors: Kresge E. N. 
Published: February 2011

Abstract
Thermoplastic elastomers based on blends of polyolefins are an important family of engineering materials. Their importance arises from a combination of rubbery properties along with their thermoplastic nature in contrast to thermoset elastomers. The development of polyolefin thermoplastic elastomer blends follows somewhat that of thermoplastic elastomers based on block copolymers such as styrene-butadiene-styrene triblock copolymer and multisegmented polyurethane thermoplastic elastomers which were instrumental in showing the utility of thermoplastic processing methods. Polyoleflns are based on coordination catalysts that do not easily lend themselves to block or multisegmented copolymer synthesis. However, since polyolefins have many important attributes favorable to useful elastomeric systems, there was considerable incentive to produce thermoplastic elastomers based on simple α-olefins by some means. Low density, chemical stability, weather resistance, and ability to accept compounding ingredients without compromising physical properties are highly desirable. These considerations led to the development of polyolefin thermoplastic elastomer blends, and two types are now widely used: blends of ethylene-propylene rubber (EPM) with polypropylene (PP) and blends of EPDM and PP in which the rubber phase is highly crosslinked. This article reviews the nature of these blends. Both physical and Theological properties are very dependent on the morphology and crosslink density of the blend system. Moreover, the usefulness of practical systems depends extensively on compounding technology based on added plasticizers and fillers.
Analysis of Resistivity in a Rubber Compound
Authors: Fernández D. Roig , Marzocca A. J. 
Published: February 2011

Abstract
In the tire industry, good dispersion of carbon black in the rubber matrix is very important to obtain optimum mechanical properties of the compound. Usually, this dispersion can be classified in macrodispersion (for particles bigger than 10 μm) and microdispersion (for those smaller than 10 μm). It is known that good microdispersion enables better fatigue resistance and wear. If it is desired to control the degree of dispersion of uncured compounds during the different processes in the factory, it would be necessary to have a simple and rapid test to do it. An appropriate method to detect different degrees of dispersion is based on the measurement of the electrical resistivity of the rubber compound with dc or ac. In recent years, different factors that affect the resistivity of the compounds were studied in several research programs. The internal factors include structure, size, and dispersion of carbon-black particles, the presence of other reinforcement (silica), and the polymer class. Other factors studied are external: mixing level, pressure, temperature, aging, and contact resistance. Boonstra showed that resistivity depends on the degree of dispersion of carbon black. In his paper, resistivity data are compared with the dispersion levels according to the Cabot rating with good correlation. Furthermore, there are several electrical conduction mechanisms that are proposed in the literature to explain experimental data. It is the purpose of this paper to present an improvement of the Boonstra device for the measurement of electrical resistivity of uncured compounds. The influence of temperature, pressure, aging, carbon black level, and time on the mill roll over the electrical resistivity were also studied. Finally, the results were analyzed by a probability model.
Effect of Different Surface Modifications on the Adhesion of Vulcanized Styrene-Butadiene Rubber
Authors: Martín-Martínez J. M. , Fernández-García J. C. , Huerta F. , Orgilés-Barceló A. C. 
Published: February 2011

Abstract
From the above results, the following conclusions may be drawn: 1. A water ultrasonic procedure for cleaning SBR surfaces has been proposed. The peel strengths attained with polyurethane adhesives are not great and increase with the amount and especially with the viscosity of the adhesive. 2. Surface roughening improves the adhesion between SBR and PUA. There are no important changes in peel strength with the amount and viscosity of the PUA. Zinc stearate removal could be responsible for the increase in peel strength. 3. Chlorination of SBR surface increases the peel strength with regard to ultrasonic-cleaned rubber, especially when both SBR test strip pieces are halogenated. This increase depends on the solvent and percentage of TIC, as well as the amount and viscosity of the adhesive. However, the type of solvent for TIC does not induce physical differences in the SBR surface, the variations being explained in terms of the extent of the chlorine reaction with double carbon bonds of butadiene; in fact, IR spectra show some bands due to the C-C1 groups and also for carboxylic groups. On the other hand, SBR chlorination creates cracks in the surface which are larger when the amount of TIC increases. Furthermore, peel strength, contact angle, and surface analysis measurements correspond well. 4. There is a degradation of the PUA during the time when chlorine reacts with the SBR surface. This reaction is favored by large TIC amounts when MEK is the solvent, and there are low adhesive viscosities. 5. The variation of the adhesion strength with the percentage of TIC depends more on the kind of solvent employed to disperse the halogen-precursor than on the chemical nature of the polyurethane adhesive, probably due to a chemical reaction between them which leads to different chlorinated products.
Pulsed NMR Study of Motional Heterogeneity in Acrylonitrile-Butadiene/Poly(Vinyl Chloride) Blends
Authors: Fukumori Kenzo , Sato Norio , Kurauchi Toshio 
Published: February 2011

Abstract
Motional heterogeneity in blends of NBR (AN = 38%) and PVC was studied by 1H pulsed NMR. It was estimated from NMR relaxation measurements that the PVC molecules in the NBR phase form phase domains of the order of less than 10 nm, consistent with the microheterogeneous structure observed by TEM. Furthermore, by spin diffusion experiments using the Goldman-Shen pulse sequence, the size of the PVC phase domains was semiquantitatively evaluated to be 4.2 nm in the case of the cylindrical domains and to be 5.1 nm in the case of the spherical domains. It becomes clear that pulsed NMR complements the results of other analytical methods with more detailed information on the state of the molecular mixing in the blends.