bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cutaneous Reactions to Rubber
Authors: Taylor James S. , Leow Yung-Hian 
Published: February 2011

Abstract
The three major adverse cutaneous reactions to rubber include natural rubber latex allergy, irritant contact dermatitis and allergic contact dermatitis. An overview of relevant aspects of the types of natural and synthetic rubber, rubber production, and specific chemicals used in compounding and vulcanization, as well as latex proteins is essential to an understanding of these reactions. Natural rubber latex allergy is a type I, IgE mediated, immediate hypersensitivity reaction to one or more proteins present in natural rubber latex with clinical manifestations ranging from contact urticaria to allergic rhinitis, asthma, and anaphylaxis. Over the past decade, natural rubber latex allergy has become a major medical, occupational health, and medicolegal problem. Individuals at highest risk are patients with spina bifida and health care workers. Diagnosis is based largely on clinical history and examination, and serologic and intracutaneous testing. Irritant contact dermatitis is non-immunologic and is the most common cutaneous reaction to rubber. Cumulative exposure to low-grade irritants impairs the barrier function of the skin and allows penetration of potential irritants and allergens. Diagnosis is based on history of exposure to known irritants, cutaneous examination, and exclusion of allergy. Allergic contact dermatitis is a type IV cell mediated, delayed hypersensitivity reaction which occurs primarily from exposure to rubber chemicals either directly or from residual amounts present in rubber products. Most cases present with an eczematous dermatitis, but purpura, lichenoid dermatitis, and depigmentation occasionally occur. Diagnosis is made on the basis of history, examination, and epicutaneous patch testing with rubber chemicals and rubber products. Treatment is with allergen and irritant avoidance and substitution, environmental control, personal protective equipment and topical and systemic pharmacologic therapy. A unified approach is needed in the diagnosis and treatment of adverse cutaneous reactions to rubber and it is important to remember that some patients may have both contact dermatitis and natural latex allergy. Determining the bioavailability and elicitation threshold of rubber allergens may be helpful in reducing allergic reactions from consumer and industrial rubber products.
A Historical Perspective and Review of Elastomeric Stick—Slip
Authors: Rorrer Ronald A. L. 
Published: February 2011

Abstract
Stick—slip sliding of elastomers is an important subtopic to the general topic of the sliding friction of elastomers. This paper provides a review of the experimental and analytical work that has occurred over the last 50 years on stick—slip sliding. Both dry and lubricated sliding of elastomers are reviewed. Stick—slip of elastomers is traced from the early experimental work on friction of the 1950–1960s through the more recent experimental and modeling results of the 1980–1990s. From the literature the common driving mechanism for both wet and dry sliding is most often attributed to a negative slope for friction as a function of velocity.
Rubber Friction on Self-Affine Road Tracks
Authors: Klüppel Manfred , Heinrich Gert 
Published: February 2011

Abstract
A basic theoretical concept of rubber friction on rough surfaces is presented that relates the frictional force to the dissipated energy of the rubber during sliding stochastic excitations on a broad frequency scale. It is shown that this is of high relevance for tire traction and allows for a prediction of the likely level of friction of tread compounds on the basis of viscoelastic data. The impact of both, the frequency dependent loss- and storage modulus on the frictional force during sliding of tires on rough tracks, is demonstrated quantitatively for different sliding velocities. The effect of the surface roughness of road tracks is described by three characteristic surface descriptors, i.e., the fractal dimension and the correlation lengths parallel and normal to the surface. These descriptors can be obtained from a fractal analysis of the road texture via stylus- or laser measurements. In particular, it is shown that the applied model of rubber friction is in agreement with the classical friction data of Grosch, who found a broad maximum for the friction coefficient with increasing sliding speed. The broadness of the friction maximum is shown to be directly related to the broadness of the roughness scale of the surface.
Evaluating the Durability of Silicone Duplex Coatings Using a Scratch Tester
Authors: Kohl J. G. , Singer I. L. , Griffith J. R. 
Published: February 2011

Abstract
Scratch tests were used to evaluate the durability of duplex elastomeric coatings under single pass, continuous loading, low speed sliding contact. The coatings consisted of a softer elastomer top layer (effective modulus = 3 MPa) on a stiffer elastomer bond layer (effective modulus = 23 MPa) on epoxy-coated steel. Duplex coating thicknesses ranged from 0.1 to 1 mm. Two different scratch styli were used: a 1.6 mm radius steel ball and a conical pin with a 0.8 mm radius diamond tip. The tangential force increased monotonically with normal force, then dropped suddenly; the onset of this drop is defined as the critical tangential force, Tc. Tc increased linearly with increases in both bond and top coat thicknesses, but the thickness dependence of the bond coat was 2 to 3 times more than that of the top coat. Optical and Raman microscopy of scratch tracks associated the damage at Tc with either tearing of the top coat behind the slider or debonding of the bond coat ahead of the slider or a combination of both. The thickness dependence of Tc is discussed qualitatively in terms of both stress and fracture mechanics models that account for damage to elastomer-coated substrates.
Thermal Degradation Studies of a Polyurethane Propellant Binder
Authors: Celina M. , Graham A. C. , Gillen K. T. , Assink R. A. , Minier L. M. 
Published: February 2011

Abstract
The thermal oxidative aging of a crosslinked hydroxy-terminated polybutadiene (HTPB)/isophorone diisocyanate (IPDI) based polyurethane rubber, used as a polymeric binder in solid propellant grain, was investigated at temperatures from 25 to 125 °C. The changes in tensile elongation, polymer network properties and chain dynamics, mechanical hardening and density were determined with a range of techniques including modulus profiling, solvent swelling, NMR relaxation and O2 permeability measurements. We critically evaluated the Arrhenius methodology that is commonly used with a linear extrapolation of high temperature aging data using extensive data superposition and highly sensitive oxygen consumption experiments. The effects of other constituents in the propellant formulation on aging were also investigated. We conclude that crosslinking is the dominant process at higher temperatures and that the degradation involves only limited hardening in the bulk of the material. Significant curvature in the Arrhenius diagram of the oxidation rates was observed. This is similar to results for other rubber materials.
On the Reason that Passenger Tire Sidewalls are Based on Blends of Natural Rubber and cis-Polybutadiene
Authors: Kim H. J. , Hamed G. R. 
Published: February 2011

Abstract
A tire sidewall must have good resistance to fracture over a range of conditions covering rapid as well as slow crack growth. A vulcanizate based on a 50/50 natural rubber (NR)/cis-butadiene rubber (cis-BR) blend seems to meet this requirement. It retains the ability for longitudinal crack branching and has catastrophic rupture resistance near that of a corresponding NR vulcanizate. At the same time, the blend has good resistance to slow fatigue crack growth, much like that of a cis-BR vulcanizate. The combination of desired properties in the blend may result from co-continuity of its NR and BR phases.
Energy Release Rate for a Crack in a Tilted Block
Authors: Gent A. N. , Razzaghi-Kashani M. 
Published: February 2011

Abstract
Approximate relations were obtained previously for the tilting stiffness of a rubber block bonded between two rigid plates, assuming linear elastic behavior.1 They take into account restrictions placed on the deformation by the bonded surfaces, a feature that becomes extremely important for thin blocks of an incompressible material. Results are reviewed here for two special cases: an infinitely wide or a relatively narrow block. In both cases the length and width are assumed to be large compared to the block thickness. Approximate values are then derived for the energy release rate G for a relatively deep crack running into the block on the tension side, parallel to the bonded surface. Values for tilting stiffness and energy release rate have also been calculated by finite element analysis (FEA) for slightly compressible rubber blocks, with Poisson's ratio in the range: 0.49 to 0.5, and for blocks of various thicknesses. Good agreement is obtained with the approximate theory for deep cracks, when the assumptions on which the theory is based are more likely to be valid. Application of repeated tilting deformations to a bonded rubber block appears to be a simple way of measuring crack growth rates under mechanical fatigue. Moreover, a wide range of energy release rates can be employed using a single specimen.
Chemical Interaction and Phase Morphology Development of Carboxy Terminated Butadiene-co-Acrylonitrile Rubber Toughened Epoxy Blends
Authors: Vineeta Nigam , Setua D. K. , Mathur G. N. 
Published: February 2011

Abstract
The nature of chemical interaction between carboxy terminated butadiene-co-acrylonitrile (CTBN), a reactive liquid rubber, and epoxy cresol novolac (ECN) resin during curing with diamino diphenyl methane (DDM) as hardener has been studied by Fourier transform infrared spectroscopy (FTIR). Blends of CTBN and ECN were withdrawn at a regular interval of 15 min for 2 h and the FTIR spectra were recorded in each case. Variations of the positions of the characteristic peaks of the oxirane group of epoxy and carboxyl group of CTBN as well as formation of several new peaks with the progress of the curing were observed. Scanning electron microscopy (SEM) was conducted in each of the above samples to study the evolution of phase morphology through growth of the rubber phase while the continuous epoxy matrix underwent curing by the hardener. The surface topography and microstructure of impact-failed toughened epoxies have also been studied with the help of atomic force microscopy (AFM).
Carbon Black and Fullerenes: New Discoveries in Early Formation Mechanisms and Nucleation
Authors: Johnson M. Pontier , Locke R. W. , Donnet J. B. , Wang T. K. , Wang C. C. , Bertrand P. 
Published: February 2011

Abstract
Recent studies on the formation of carbon black have resulted in the previously unreported finding of buckminster-fullerene, C60, in trace quantities in the toluene extractable materials. High-resolution transmission electron microscopy (HRTEM) experiments indicate the molecule may be functioning as a nucleation site in the formation of primary particles of carbon black. Time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) provided the surface chemical analysis of conventional and experimental carbon blacks. The toluene extracts represented the precursor compounds present in the gaseous phase at the time of quench. The extracts were analyzed by Fourier transform infrared (FTIR) spectroscopy, liquid chromatography (LC)/mass spectroscopy (MS) and elemental composition. The data, taken as a whole, have led to a more clear understanding of the competitive chemical pathways occurring during the inception and nucleation of a primary particle of carbon black. Direct observation of nucleation sites and types are possible with HRTEM analysis.
Characterization of Ground Rubber Tire and its Effect on Natural Rubber Compound
Authors: Naskar Amit K. , De S. K. , Bhowmick A. K. , Pramanik P. K. , Mukhopadhyay R. 
Published: February 2011

Abstract
Ground rubber tire (GRT) particles of different sizes were characterized and the effect of these particles in a natural rubber (NR) compound was studied. It is found that smaller particles contain less polymer, but have higher amounts of fillers and metals with respect to polymer. NR compound containing smaller GRT particles shows better physical properties, but poorer aging characteristics.
Use of Atomic Force Microscope as a Nanoindenter to Characterize Elastomers
Authors: Mareanukroh Methporn , Eby R. K. , Scavuzzo R. J. , Hamed Gary R. , Preuschen Judith 
Published: February 2011

Abstract
The atomic force microscope (AFM) in the force mode has been used as a nanoindenter for determining the crosslink density and modulus of rubber on a fine scale. The force—distance curves obtained as the sample is moved against the tip can render information about mechanical properties of the sample. The technique for this purpose has been established. Several instrumental and technical difficulties encountered during the development of the technique have been identified and solved. The difficulties include surface roughness, thickness variation of the sample, hysteresis of the scanner, determining the stiffness of the cantilever, determining the geometry of the tip, converting the sensor output to force and determining the penetration depth of the tip. The determination of the effective tip geometry requires use of a calibration material. Force—distance measurements were made on a series of styrene-butadiene rubbers (SBR) with different crosslink densities. The modulus determined by AFM agreed with the modulus measured with dynamic mechanical analysis. The results of force/penetration depth show a linear relationship with crosslink density. The AFM results are shown to correlate with those from NMR. The effects of rubber oxidation in air were examined. The results show that both homogeneous and heterogeneous oxidation can be detected by this method.
Prediction of Rheometric Properties of Compounds by Using Artificial Neural Networks
Authors: Schwartz Gustavo Ariel 
Published: February 2011

Abstract
The ability of an Artificial Neural Network (ANN) to evaluate the variability of rheometric properties of rubber compounds from their formulation is presented. Because of the complexity and non-linearity of mixing processes, an exact mathematical treatment of the problem is extremely difficult, or even impossible. The use of artificial neural networks (ANNs) might be very useful to analyze these processes, since they have the ability to map nonlinear relationships without prior information about process or system models. In this work a three-layer ANN is used and the optimum parameters are determined. The results are compared with theoretical and experimental published data. The dependence of the rheometric properties as a function of compound components is also analyzed. Finally, the sensibility matrix concept is introduced. The sensibility matrix allows us to calculate the minimum expected variability, for a given compound, due to the weight tolerances of its components.
The Action of N-(Cyclohexylthio)Phthalimide as a Prevulcanization Inhibitor of 2-Bisbenzothiazole-2,2′-Disulfide Accelerated Sulfur Vulcanization
Authors: Gradwell Michael H. S. , Stephenson Nigel R. 
Published: February 2011

Abstract
Prevulcanization inhibitors (PVI) provide an important delay in the curing reactions that occur in accelerated sulfur vulcanization. In this study, the reactions of N-(cyclohexylthio)phthalimide (CTP) with other curatives (excluding zinc oxide) were investigated in the presence and absence of rubber. The CTP has been shown to react very readily with 2-mercaptobenzothiazole (MBT) and this reaction has previously been credited with the delay observed. However, recent studies have shown that MBT is not formed until crosslinking has started. In a 2-bisbenzothiazole-2,2′-disulfide (MBTS) accelerated sulfur cure, CTP was shown not to delay the onset of crosslinking, but once crosslinking began, with the concurrent formation of MBT, the CTP reacted with the MBT inhibiting further polysulfide formation, pendent group formation and thus crosslinking. Crosslinking continues after the CTP has been consumed.
Swelling of Constrained Rubber Layers: Effect on Free Energy of Detachment
Authors: Gent A. N. , Hung W. J. , Tse M. F. 
Published: February 2011

Abstract
The degree of swelling of a rubber layer by a compatible liquid has been calculated for cases when the layer is constrained, for example when it is bonded to a rigid substrate. The stored energy residing in swollen layers is also computed. From these results the amount of energy is determined that becomes available if a bonded layer separates from a substrate and then becomes free to swell further. The released energy is shown to be quite high, of the order of 10 MJ/m3 in a representative case. Attention is drawn to the importance of the layer thickness when this energy is applied to bond rupture. For layers having a thickness of the order of 1 mm or greater, the available energy is greater than the intrinsic strength of the bond or of the swollen elastomer itself. In accord with this conclusion, soft rubber layers, sandwiched between and bonded to flexible but inextensible backings, are observed to separate spontaneously and then tear away from the backing when swollen by a compatible liquid. And layers that are still attached to the backing become sharply curved before tearing loose, in rough agreement with the theoretical predictions.
Synthesis, Bromination and Cure of Isobutylene/Isoprene/P-Methylstyrene and Isobutylene/Isoprene/Styrene Terpolymers
Authors: Kaszas Gabor , Tran Binh 
Published: February 2011

Abstract
High molecular weight isobutylene/isoprene/p-methylstyrene and isobutylene/isoprene/styrene terpolymers containing up to 10.6 mol% p-methylstyrene and 3.6 mol% styrene were synthesized using “H2O”/AlCl3 as an initiator/coinitiator system in methylchloride at -95 °C. p-Methylstyrene was found to be uniformly distributed in the chains due to its similar reactivity to isobutylene. In contrast, styrene had a lower reactivity than isobutylene or even isoprene, resulting in low conversion of the styrene monomer. The reactivity ratios obtained were in good agreement with the published values. Up to about 3 mol% styrenic monomer content, the Tg of the terpolymers showed no significant increase. The isoprene units of the terpolymers were brominated by the conventional bromination technique. During bromination, some of the aromatic rings also underwent bromination. The extent of this reaction was found to be much lower in the case of p-methylstyrene than in the case of styrene. The brominated terpolymers were cured using ZnO. The brominated terpolymers displayed much faster cure, higher maximum torque and modulus at the same brominated isoprene concentration than brominated copolymers of isobutylene and isoprene, indicating that the aromatic rings participate in the cure. The brominated terpolymers showed an increased resistance to hot air aging, compared to brominated polymers containing no styrenic termonomer.
The Friction and Wear of Rubber Part 1: Effects of Dynamically Changing Slip Direction and the Damage Orientation Distribution Function
Authors: Gerrard David P. , Padovan Joe 
Published: February 2011

Abstract
In Part 1, results of an experimental and analytical study are offered which examined the effects of a dynamically changing slip direction on a rubber surface's friction and wear performance and on the properties of an industrial abrasive. For a filled SBR compound, it was found that a dynamically changing slip direction had a small effect on the friction/traction performance, but a substantial beneficial effect on the surface's wear performance. The abrasive's ability to generate wear was found to be strongly dependent on the accumulation of side slip over the life of the abrasive. Conceptualization of the Damage Orientation Distribution Function is offered to describe the statistical nature of the oriented damage generated on a slipping rubber surface. The experimental results are shown to be in excellent agreement with model predictions based on several simple assumptions regarding the effects that changing slip orientation has on the response of the Distribution Function.
Influence of Novel Electron Beam Modified Surface Treated Dual Phase Filler on Rheometric and Mechanical Properties of Styrene Butadiene Rubber Vulcanizates
Authors: Shanmugharaj A. M. , Bhowmick Anil K. 
Published: February 2011

Abstract
Rheometric and mechanical properties, hysteresis and swelling behavior of the Styrene-Butadiene Rubber vulcanizates (SBR) filled with unmodified and novel electron beam modified surface treated dual phase fillers were investigated. Scorch time increases for these modified filler loaded vulcanizates due to introduction of quinone type oxygen on the surface. Electron beam modification of dual phase filler in the absence of trimethylol propanetriacrylate (TMPTA) or triethoxysilylpropyltetrasulphide (Si-69) significantly improves the modulus of the SBR vulcanizates, whereas the values of tensile strength and elongation at break drop. However, presence of TMPTA or silane slightly increases the modulus with significant improvement in tensile strength. This effect is more pronounced at higher loading of these modified fillers in SBR vulcanizates. These variations in modulus and tensile strength are explained by the equilibrium swelling data, Kraus plot and a new mathematical model interpreting the polymer-filler interaction. Hysteresis loss ratio of SBR vulcanizates loaded with irradiated fillers in absence and presence of TMPTA or silane increases due to highly aggregated structure of the filler.
Effects of Thermal Aging on The Mechanical Properties of Natural Rubber
Authors: South Joseph T. , Case Scott W. , Reifsnider Kenneth L. 
Published: February 2011

Abstract
The focus of this research was to investigate the effect of thermal degradation upon the mechanical properties of a natural rubber compound. We examined both the quasi-static and dynamic mechanical properties of a natural rubber vulcanizate which had been subjected to isothermal, anaerobic aging. The thermal aging was conducted between the temperatures of 80 °C and 120 °C for times ranging from 3 to 24 days. The effect of thermal degradation was measured using the changes in the crosslink distribution of the vulcanizates as functions of time at temperature. A master curve relationship between the crosslink distribution of the vulcanizates due to thermal degradation and the static and dynamic mechanical properties has been developed. It was found that the both the quasi-static and dynamic mechanical properties correlated with the percentage of poly and monosulfidic crosslinks, where in general higher levels of polysulfidic crosslink gave rise to the highest mechanical properties.
Novel Thermoplastic Elastomers Based on Acrylonitrile-Butadiene-Styrene Terpolymer (ABS) from Waste Computer Equipment and Nitrile Rubber
Authors: Anandhan S. , De P. P. , De S. K. , Bhowmick Anil K. , Bandyopadhyay S. 
Published: February 2011

Abstract
Acrylonitrile-butadiene-styrene terpolymer (ABS) is one of the engineering plastics most frequently used as outer casings for computer equipment such as monitors, keyboards and other similar components. In an attempt to recycle, blends of scrap computer plastics (SCP) based on ABS with nitrile rubber (NBR) were prepared and mechanical properties and morphology were studied. Effect of dynamic vulcanization on the properties of 60/40, 70/30, and 80/20 NBR/SCP blends was assessed. These blends show the thermoplastic elastomeric behavior. Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) studies show that the dynamically vulcanized NBR particles are dispersed in the ABS matrix. The thermoplastic elastomeric blends show excellent swelling resistance in IRM # 93 oil.