The Experts below are selected from a list of 41154 Experts worldwide ranked by ideXlab platform
Farid Eltantawy - One of the best experts on this subject based on the ideXlab platform.
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effect of bi containing superconducting ceramic on the volume resistivity of Butyl Rubber composites
Polymer Testing, 2004Co-Authors: N Dishovsky, Farid Eltantawy, R DimitrovAbstract:Abstract The present paper describes the effect of Bi-containing superconducting ceramic on the volume resistivity of Butyl Rubber (IIR) composites. The microstructure of Butyl Rubber filled with different concentrations of superconductor was examined by scanning electron microscopy (SEM). The influence of superconductor concentration, time, applied static pressure and temperature on the volume resistivity was investigated. The differences in volume resistivity–temperature dependencies with different filler levels under temperature increase and temperature decay were also measured. The effects observed are discussed from the viewpoint of ionic and electronic mechanisms of electrical conductivity in Rubber-based composites.
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joule heating treatments of conductive Butyl Rubber ceramic superconductor composites a new way for improving the stability and reproducibility
European Polymer Journal, 2001Co-Authors: Farid EltantawyAbstract:The present paper describes the effect of superconductors on the sintering process, apparent cross-linking density, sintering factor, hardness and volume fraction of Butyl Rubber (IIR) composites. Electrical conductivity and I–V characteristics at various processing conditions of IIR with different concentrations of superconductor were measured. The stability and reproducibility of IIR composites were tested. Also, the conduction mechanism of electrical conductivity is discussed. Specific heat and the amount of heat transferred by radiation and convection were calculated via the proposed model and calorimetry as a function of superconductor content. It was found that superconductor accelerates the driving force during the sintering process and the characteristic time constant during sintering decreases while the sintering factor, the apparent cross-linking density, hardness and volume fraction of Rubber increases as the content of superconductor increases. In addition, it was proved that the superconductor and Joule heating effect improves the electrical and thermal properties of IIR.
R Dimitrov - One of the best experts on this subject based on the ideXlab platform.
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effect of bi containing superconducting ceramic on the volume resistivity of Butyl Rubber composites
Polymer Testing, 2004Co-Authors: N Dishovsky, Farid Eltantawy, R DimitrovAbstract:Abstract The present paper describes the effect of Bi-containing superconducting ceramic on the volume resistivity of Butyl Rubber (IIR) composites. The microstructure of Butyl Rubber filled with different concentrations of superconductor was examined by scanning electron microscopy (SEM). The influence of superconductor concentration, time, applied static pressure and temperature on the volume resistivity was investigated. The differences in volume resistivity–temperature dependencies with different filler levels under temperature increase and temperature decay were also measured. The effects observed are discussed from the viewpoint of ionic and electronic mechanisms of electrical conductivity in Rubber-based composites.
Elizabeth R. Gillies - One of the best experts on this subject based on the ideXlab platform.
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Carboxylic Acid-Functionalized Butyl Rubber: Synthesis, Characterization, and Physical Properties
2015Co-Authors: Matthew J. Mceachra, Joh F. Tra, Inderpree Sra, Joh R. De Bruy, Elizabeth R. GilliesAbstract:PolyisoButylene (PIB) and other PIB-based materials are of significant interest for a vast array of applications, but chemical modification is often required to obtain the desired properties. Described here are two new approaches for the preparation of carboxylic acid-functionalized PIB. The ring opening of cyclic anhydrides from an allylic alcohol derivative of Butyl Rubber and the atom transfer radical polymerization of tert-Butyl methacrylate from a Rubber derivative both ultimately afford carboxylated materials. These materials displayed significantly enhanced adhesion to stainless steel, as well as increased ultimate tensile strength and Young’s modulus in comparison to unmodified Rubbers. Rheological studies suggested that they exhibit a greater degree of cross-linking-type behavior than the parent Butyl Rubber. Combined, these studies suggest that the properties of PIB can be readily tuned through synthetic modifications of the backbone, even at low mole percent, and that carboxylic acid moieties can impart desirable properties for various applications
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synthesis and application of cinnamate functionalized Rubber for the preparation of uv curable films
European Polymer Journal, 2013Co-Authors: Wei Wu, Solmaz Karamdoust, Bethany A Turowec, Elizabeth R. GilliesAbstract:Abstract A Butyl Rubber derivative that can be cured upon exposure to UV light in the absence of additional chemical additives was developed. This polymer was prepared by the reaction of hydroxyl-functionalized Butyl Rubber with cinnamoyl chloride to provide a cinnamate functionalized Rubber. The cinnamate content was varied by starting with derivatives prepared from Butyl Rubber containing either 2 or 7 mol% isoprene. The kinetics of the cross-linking was studied by UV–visible spectroscopy and it was found to vary according to the film thickness. The changes in gel content and volume swelling ratio with irradiation time were dependent on the cinnamate content. Toxicity studies suggested that the cross-linked materials do not leach toxic molecules. The approach was also applied to obtain cross-linked films of Butyl Rubber-poly(ethylene oxide) graft copolymers, leading to surfaces that resisted the adhesion and growth of cells. Thus the approach is versatile and is of particular interest when non-leaching coatings of cross-linked Butyl Rubber are desired for biomedical or other applications.
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Rubber functionalization by diels alder chemistry from cross linking to multifunctional graft copolymer synthesis
Macromolecules, 2013Co-Authors: Mahmoud Abd Rabo M Moustafa, Elizabeth R. GilliesAbstract:The functionalization of polyisoButylene-co-isoprene, commonly referred to as Butyl Rubber, was investigated with the aim of preparing multifunctional materials. First, the acid catalyzed ring-opening of epoxidized Butyl Rubber was investigated. Ring-opening followed by elimination resulted in the formation of different dienes depending on the reaction conditions. It was possible to cleanly isolate the exo-diene, which readily undergoes Diels–Alder [4 + 2] cycloaddition reactions and it was demonstrated that this chemistry could be used to prepare multifunctional graft copolymers. For example, poly(ethylene oxide) (PEO) or polystyrene (PS) could be grafted while at the same time introducing carboxylic acid moieties along the polymer backbone, and both polymers could be simultaneously grafted to form mixed graft copolymers with tunable tensile properties. Furthermore, it was demonstrated that reaction with a dimaleimide led to efficient cross-linking of the Rubber and this cross-linking could be reversed u...
Kay Saalwachte - One of the best experts on this subject based on the ideXlab platform.
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hierarchical sticker and sticky chain dynamics in self healing Butyl Rubber ionomers
Macromolecules, 2019Co-Authors: Anto Mordvinki, Marcus Suckow, Frank Ohme, Ralph H Colby, Costantino Creto, Kay SaalwachteAbstract:We present a detailed comparison of the microscopic dynamics and the macroscopic mechanical behavior of novel Butyl Rubber ionomers with tunable dynamics of sparse sticky imidazole-based sidegroups that form clusters of about 20 units separated by essentially unperturbed chains. This material platform shows promise for application as self-healing elastomers. Size and thermal stability of the ionic clusters were probed by small-angle X-ray scattering, and the chain and sticker dynamics were studied by a combination of broadband dielectric spectroscopy (BDS) and advanced NMR methods. The results are correlated with the rheological behavior characterized by dynamic–mechanical analysis (DMA). While the NMR-detected chain relaxation and DMA results agree quantitatively and confirm relevant aspects of the sticky-reptation picture on a microscopic level, we stress and explain that apparent master curves are of limited use for such a comparison. The cluster-related relaxation time detected by BDS is much shorter ...
Yanxi Wei - One of the best experts on this subject based on the ideXlab platform.
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comparative study on the treatment of simulated brominated Butyl Rubber wastewater by using bipolar membrane electrodialysis bmed and conventional electrodialysis ed
Separation and Purification Technology, 2013Co-Authors: Yanxi Wei, Yaoming Wang, Xu ZhangAbstract:Abstract A large amount of wastewater containing sodium bromide (NaBr) is generated during the production of brominated Butyl Rubber. In our previous job, bipolar membrane electrodialysis (BMED) was used to regenerate hydrobromic acid (HBr) and sodium hydroxide (NaOH) from a simulated NaBr wastewater. To give a comparison with previously presented research paper, a desalinization of sodium bromide by using ED was also performed. The effects of operation parameters, such as current density, sodium bromide concentration, and initial acid and base concentrations in the concentrate, on desalinization were analyzed. In comparison, BMED has higher desalinization ratio and current efficiency, and much lower voltage drop and energy consumption. The process cost is estimated to be 0.82 $/kg NaBr for BMED and 1.01 $/kg NaBr for ED. Notably, BMED can also regenerate NaOH and HBr. Therefore, BMED will be more economically attractive and environmental benignity due to the regeneration of useful resource and prevention of secondary pollution.
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treatment of simulated brominated Butyl Rubber wastewater by bipolar membrane electrodialysis
Separation and Purification Technology, 2011Co-Authors: Yanxi Wei, Yaoming Wang, Xu ZhangAbstract:Abstract A large amount of wastewaters containing sodium bromide (NaBr) is usually generated during the production of brominated Butyl Rubber; it can cause contamination of the environment. In this study, a method was reported to regenerate hydrobromic acid (HBr) and sodium hydroxide (NaOH) from a simulated NaBr wastewater by bipolar membrane electrodialysis (BMED). Sodium hydroxide may be recycled in the neutralization washing process of preparing the brominated Butyl Rubber. The effects of operation parameters, such as sodium bromide concentration, current density, and initial acid and base concentrations, on regeneration were analyzed, on the basis of proper energy consumption and current efficiency. The results indicated that a low energy consumption and a high current efficiency were achieved when the concentration of sodium bromide was in the range of 11,000–16,000 mg/L with both the initial concentration of the acid and base at about 0.10 mol/L. Additionally, it was also demonstrated that a high current density applied to the BMED stack usually resulted in both higher energy consumption and current efficiency. Finally, a discharged NaBr concentration of 133.9 mg/L, which was far below the discharge standard of water pollutants for industry, could be obtained from the initial concentration of 16,000 mg/L after the operation of BMED process for 3.5 h. Therefore, this process cannot only achieve the elimination of environmental pollution, but also the recycling of resources.
