The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Giridhar Madras - One of the best experts on this subject based on the ideXlab platform.
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Ultrasonic degradation of Poly(Methyl Methacrylate-co-alkyl acrylate) coPolymers.
Ultrasonics sonochemistry, 2009Co-Authors: Vinod Kumar Konaganti, Giridhar MadrasAbstract:The coPolymers, Poly(Methyl Methacrylate-co-Methyl acrylate) (PMMAMA), Poly(Methyl Methacrylate-co-ethyl acrylate) (PMMAEA) and Poly(Methyl Methacrylate-co-butyl acrylate) (PMMABA), of different compositions were synthesized and characterized. The effect of alkyl acrylate content, alkyl group substituents and solvents on the ultrasonic degradation of these coPolymers was studied. A model based on continuous distribution kinetics was used to study the kinetics of degradation. The rate coefficients were obtained by fitting the experimental data with the model. The linear dependence of the rate coefficients on the logarithm of the vapor pressure of the solvent indicated that vapor pressure is the crucial parameter that controls the degradation process. The rate of degradation increases with an increase in the alkyl acrylate content. At any particular coPolymer composition, the rate of degradation follows the order: PMMAMA > PMMAEA > PMMABA. It was observed that the degradation rate coefficient varies linearly with the mole percentage of the alkyl acrylate in the coPolymer.
Thieo E. Hogen-esch - One of the best experts on this subject based on the ideXlab platform.
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Stereocomplex formation in Polybutadiene-syndiotactic Poly(Methyl Methacrylate) block coPolymers blended with isotactic Poly(Methyl Methacrylate): Influence of molar masses
Polymer Bulletin, 1994Co-Authors: M. P. Berkoukchi, G. Hlary, G. Blorgey, Thieo E. Hogen-eschAbstract:The process of stereocomplexation in blends of isotactic Poly(Methyl Methacrylate)s and Polybutadiene-syndiotactic Poly(Methyl Methacrylate) diblock coPolymers was studied by DSC as a function of molar mass of the constituents, annealing time and temperature. The amount of complex formed is dependent on these three parameters, while the temperature of decomposition of the complex is only dependent on the annealing temperature. Complex formation can be observed in blends containing a coPolymer with a very low molar mass syndiotactic Poly(Methyl Methacrylate) block (Mn=700)
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Stereocomplex formation in Polybutadiene-syndiotactic Poly (Methyl Methacrylate) block coPolymers blended with isotactic Poly (Methyl Methacrylate)
Polymer, 1992Co-Authors: Gérard Hélary, G. Belorgey, Thieo E. Hogen-eschAbstract:The process of stereocomplexation in blends of isotactic Poly(Methyl Methacrylate)s and Polybutadiene-syndiotactic Poly(Methyl Methacrylate) diblock coPolymers was studied by differential scanning calorimetry as a function of molar mass of the constituents, annealing time and temperature. The amount of complex formed is dependent on these three parameters, while the temperature of decomposition of the complex is only dependent on the annealing temperature. Complex formation can be observed in blends containing a coPolymer with a very low molar mass syndiotactic Poly(Methyl Methacrylate) block (Mn=700). In contrast to homoPolymer blends, for which two endotherms of decomposition were generally reported, only one endotherm is observed for coPolymer-homoPolymer blends. This behavior is attributed to the elastomer block.
Koji Nishida - One of the best experts on this subject based on the ideXlab platform.
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Studies on random coil-helix transformation of syndiotactic Poly(Methyl Methacrylate) and stereospecific template Polymerization of Methyl Methacrylate in the presence of syndiotactic Poly(Methyl Methacrylate)
Reactive & Functional Polymers, 2003Co-Authors: Mitsufumi Nodono, Takayuki Makino, Koji NishidaAbstract:Syndiotactic Poly(Methyl Methacrylate) was utilized to gain a template effect and achieve stereospecific radical Polymerization of Methyl Methacrylate. The random coil-helix transformation of syndiotactic Poly(Methyl Methacrylate) in Methyl Methacrylate was observed and the physical gelation behavior was investigated. Also, the helices of syndiotactic Poly(Methyl Methacrylate) in Methyl Methacrylate have a significant effect on the template radical Polymerization of Methyl Methacrylate. The concentration of the template Polymer as well as the conversion strongly affected the template effect.
Gérard Hélary - One of the best experts on this subject based on the ideXlab platform.
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biomimetic Poly Methyl Methacrylate based terPolymers modulation of bacterial adhesion effect
Biomacromolecules, 2002Co-Authors: Sandrine Erlo, Gérard Hélary, Zoubida Aissaoui, Graciela Pavondjavid, Joel Elleney, Marcel Jozefowicz, Veronique MigonneyAbstract:Adherence of Staphylococcus aureus, responsible for major foreign body infections, was assessed onto functionalized Poly(Methyl Methacrylate)-based terPolymers bearing sulfonate and carboxylate groups and onto Poly(Methyl Methacrylate) as control. These terPolymers, have been synthesized by radical coPolymerization of Methyl Methacrylate, methacrylic acid, and sodium styrene sulfonate by varying the ratio R = [COO-]/[COO- + SO3-] from 0 to 1 and keeping ionic monomer content between 7 and 18%. Adsorption of fibronectin onto Poly(Methyl Methacrylate) was shown to dramatically promote bacterial adherence, whereas a strong inhibition of bacteria adherence was observed onto functionalized terPolymers containing both carboxylate and sulfonate groups. When terPolymers were predominantly functionalized by carboxylate groups, bacteria adherence was favored and reached values close to those obtained for Poly(Methyl Methacrylate). These results have been related to the distribution of the anionic groups along the m...
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Stereocomplex formation in Polybutadiene-syndiotactic Poly (Methyl Methacrylate) block coPolymers blended with isotactic Poly (Methyl Methacrylate)
Polymer, 1992Co-Authors: Gérard Hélary, G. Belorgey, Thieo E. Hogen-eschAbstract:The process of stereocomplexation in blends of isotactic Poly(Methyl Methacrylate)s and Polybutadiene-syndiotactic Poly(Methyl Methacrylate) diblock coPolymers was studied by differential scanning calorimetry as a function of molar mass of the constituents, annealing time and temperature. The amount of complex formed is dependent on these three parameters, while the temperature of decomposition of the complex is only dependent on the annealing temperature. Complex formation can be observed in blends containing a coPolymer with a very low molar mass syndiotactic Poly(Methyl Methacrylate) block (Mn=700). In contrast to homoPolymer blends, for which two endotherms of decomposition were generally reported, only one endotherm is observed for coPolymer-homoPolymer blends. This behavior is attributed to the elastomer block.
Vinod Kumar Konaganti - One of the best experts on this subject based on the ideXlab platform.
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Ultrasonic degradation of Poly(Methyl Methacrylate-co-alkyl acrylate) coPolymers.
Ultrasonics sonochemistry, 2009Co-Authors: Vinod Kumar Konaganti, Giridhar MadrasAbstract:The coPolymers, Poly(Methyl Methacrylate-co-Methyl acrylate) (PMMAMA), Poly(Methyl Methacrylate-co-ethyl acrylate) (PMMAEA) and Poly(Methyl Methacrylate-co-butyl acrylate) (PMMABA), of different compositions were synthesized and characterized. The effect of alkyl acrylate content, alkyl group substituents and solvents on the ultrasonic degradation of these coPolymers was studied. A model based on continuous distribution kinetics was used to study the kinetics of degradation. The rate coefficients were obtained by fitting the experimental data with the model. The linear dependence of the rate coefficients on the logarithm of the vapor pressure of the solvent indicated that vapor pressure is the crucial parameter that controls the degradation process. The rate of degradation increases with an increase in the alkyl acrylate content. At any particular coPolymer composition, the rate of degradation follows the order: PMMAMA > PMMAEA > PMMABA. It was observed that the degradation rate coefficient varies linearly with the mole percentage of the alkyl acrylate in the coPolymer.
