The Experts below are selected from a list of 23553 Experts worldwide ranked by ideXlab platform
Marta Fernández-garcía - One of the best experts on this subject based on the ideXlab platform.
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Kinetic study of free‐radical copolymerization of methyl acrylate and methyl methacrylate in benzene
Macromolecular Chemistry and Physics, 1996Co-Authors: Enrique López Madruga, Marta Fernández-garcíaAbstract:The variation of copolymerization rate with composition obtained for the system methyl acrylate (1)/methyl methacrylate (2)/benzene/2,2'-azoisobutyronitrile using standard techniques of polymerization rate measurements has been interpreted on the basis of a penultimate effect upon the Propagation Reaction, giving values of s 1 = 0.547 and s 2 = 1.668 for the chain-end reactivity ratios.
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A kinetic study on the radical copolymerization of dimethyl itaconate and methyl methacrylate in benzene
Polymer, 1996Co-Authors: Marta Fernández-garcía, Enrique López Madruga, Rocío Cuervo-rodríguezAbstract:Abstract The copolymerization of dimethyl itaconate and methyl methacrylate with 2,2′-azobisisobutyronitrile was investigated kinetically at 50°C in benzene. The copolymer composition conforms to the terminal model within experimental error, but the variation of the copolymerization rate shows a penultimate effect on the Propagation Reaction. Homopolymerization kinetic coefficients for dimethyl itaconate monomer were also determined.
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A kinetic study of free‐radical copolymerization of butyl acrylate with methyl methacrylate in solution
Macromolecular Chemistry and Physics, 1996Co-Authors: Enrique López Madruga, Marta Fernández-garcíaAbstract:Free-radical copolymerization at 50°C of butyl acrylate with methyl methacrylate was carried out in benzene solution using 3 and 5 mol/L as the overall concentration of monomers. Both the reactivity ratios and the rate coefficients of copolymerization are affected by the total monomer concentration. Reactivity ratios were analyzed on the basis of the “bootstrap” model, and the copolymerization rate is interpreted assuming a penultimate effect upon the Propagation Reaction.
Enrique López Madruga - One of the best experts on this subject based on the ideXlab platform.
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Kinetic study of free‐radical copolymerization of methyl acrylate and methyl methacrylate in benzene
Macromolecular Chemistry and Physics, 1996Co-Authors: Enrique López Madruga, Marta Fernández-garcíaAbstract:The variation of copolymerization rate with composition obtained for the system methyl acrylate (1)/methyl methacrylate (2)/benzene/2,2'-azoisobutyronitrile using standard techniques of polymerization rate measurements has been interpreted on the basis of a penultimate effect upon the Propagation Reaction, giving values of s 1 = 0.547 and s 2 = 1.668 for the chain-end reactivity ratios.
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A kinetic study on the radical copolymerization of dimethyl itaconate and methyl methacrylate in benzene
Polymer, 1996Co-Authors: Marta Fernández-garcía, Enrique López Madruga, Rocío Cuervo-rodríguezAbstract:Abstract The copolymerization of dimethyl itaconate and methyl methacrylate with 2,2′-azobisisobutyronitrile was investigated kinetically at 50°C in benzene. The copolymer composition conforms to the terminal model within experimental error, but the variation of the copolymerization rate shows a penultimate effect on the Propagation Reaction. Homopolymerization kinetic coefficients for dimethyl itaconate monomer were also determined.
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A kinetic study of free‐radical copolymerization of butyl acrylate with methyl methacrylate in solution
Macromolecular Chemistry and Physics, 1996Co-Authors: Enrique López Madruga, Marta Fernández-garcíaAbstract:Free-radical copolymerization at 50°C of butyl acrylate with methyl methacrylate was carried out in benzene solution using 3 and 5 mol/L as the overall concentration of monomers. Both the reactivity ratios and the rate coefficients of copolymerization are affected by the total monomer concentration. Reactivity ratios were analyzed on the basis of the “bootstrap” model, and the copolymerization rate is interpreted assuming a penultimate effect upon the Propagation Reaction.
E. Spousta - One of the best experts on this subject based on the ideXlab platform.
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Catalysis of the Propagation Reaction in Ziegler-Natta Polymerization
Journal of Polymer Science Part C: Polymer Symposia, 2007Co-Authors: K. Veselý, J. Ambrož, J. Mejzlík, E. SpoustaAbstract:The results on the catalytic action of counterions of homogeneous ionic polymerizations are reviewed. By analogy, positively charged counterious play an important role in the heterogeneous system TiCl3–AlR3. This is illustrated by the influence of “defects” in the TiCl3 on the course of a given Reaction. Counterions of different structures act in the polymerization as centers of different stereospecificity.
Wayne D Cook - One of the best experts on this subject based on the ideXlab platform.
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exotherm control in the thermal polymerization of nona ethylene glycol dimethacrylate negdm using a dual radical initiator system
Polymer, 2003Co-Authors: Wayne D CookAbstract:The curing behaviour of a long-chain dimethacrylate with a series of peroxide initiators was examined by temperature-ramping DSC. The effect of oxygen inhibition on the onset and peak temperatures cure was confirmed and the peak exotherm temperature was correlated with the decomposition rate of the initiator. The gel point temperature, obtained from temperature-ramping rheology studies, was directly related to the onset of cure from temperature-ramping DSC measurements. A combination of two peroxides with significantly different initiation rates was found to reduce the maximum heat flow and spread the polymerization process over a broader range of temperatures, thus effectively counteracting the auto-acceleration effect without significantly affecting the degree of cure. This behaviour was also predicted by with a free radical polymerization kinetic model. In order to further improve the cure behaviour, Nofmer was used as a chain transfer agent to control the Propagation Reaction in the polymerization. The use of a dual initiator system in the presence of Nofmer yielded a smooth polymerization process occurring over a wide range of temperatures and with low heat flow. Isothermal rheological studies confirmed the delay in the gel point by Nofmer.
E Gaffet - One of the best experts on this subject based on the ideXlab platform.
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enhancement of self sustaining Reaction cu3si phase formation starting from mechanically activated powders
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2000Co-Authors: F Bernard, H Souha, E GaffetAbstract:Mechanical high-energy ball milling of an 3Cu Si elemental powders mixture was used to activate a self-sustaining combustion Reaction or so-called self-sustaining high-temperature synthesis (SHS) to form the copper silicide phase, a Reaction for which the thermodynamic criterion proposed by Munir for self-Propagation Reaction is not favorable. A complete characterization of the end-products was performed with X-ray diffraction analysis and scanning electron microscopy. Thermal and structural information describing the combustion front initiated by heating up a sample to 180°C in a Cu:Si system is communicated. This paper clearly shows that the mechanically activated self-sustaining high-temperature synthesis process produces a pure Cu3Si compound in spite of the limitation imposed by the thermodynamic criterion. In addition, it seems that the reactivity of Cu3Si elaborated from the mechanically activated SHS process towards CuCl is greater than the reactivity of Cu3Si reference powder. This difference is mainly due to the crystallite size. © 2000 Elsevier Science S.A. All rights reserved.
