Documents disponibles écrits par cet auteur

Comparison of emulsification devices for the production of miniemulsions / Ula El-Jaby in Industrial & engineering chemistry research, Vol. 48 N° 22 (Novembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10147–10151 Titre : Comparison of emulsification devices for the production of miniemulsions Type de document : texte imprimé Auteurs : Ula El-Jaby, Auteur ; Michael Cunningham, Auteur ; Timothy F. L. McKenna, Auteur Année de publication : 2010 Article en page(s) : pp. 10147–10151 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Emulsification  devices  Miniemulsions Résumé : Droplets generated using ultrasonication, the rotor-stator, and static mixers have been investigated in terms of power and energy consumption, droplet distributions, and shear rates. It was observed that with energy costs being of similar orders of magnitude, the static mixers imposed less shear on the system making them the optimal choice for miniemulsification. Similarly, the absolute widths of the distributions for droplets generated with the sonicator and rotor-stator were larger than those generated with the static mixers and during polymerization underwent secondary nucleation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901005a [article] Comparison of emulsification devices for the production of miniemulsions [texte imprimé] / Ula El-Jaby, Auteur ; Michael Cunningham, Auteur ; Timothy F. L. McKenna, Auteur . - 2010 . - pp. 10147–10151. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 22 (Novembre 2009) . - pp. 10147–10151 Mots-clés : Emulsification  devices  Miniemulsions Résumé : Droplets generated using ultrasonication, the rotor-stator, and static mixers have been investigated in terms of power and energy consumption, droplet distributions, and shear rates. It was observed that with energy costs being of similar orders of magnitude, the static mixers imposed less shear on the system making them the optimal choice for miniemulsification. Similarly, the absolute widths of the distributions for droplets generated with the sonicator and rotor-stator were larger than those generated with the static mixers and during polymerization underwent secondary nucleation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901005a

Effect of Bimodality on the Adhesive Properties of Pressure Sensitive Adhesives / Gabriela E. Fonseca in Industrial & engineering chemistry research, Vol. 49 N° 16 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7303–7312 Titre : Effect of Bimodality on the Adhesive Properties of Pressure Sensitive Adhesives : Role of Bimodal Particle Size and Molecular Weight Distributions Type de document : texte imprimé Auteurs : Gabriela E. Fonseca, Auteur ; Timothy F. L. McKenna, Auteur ; Marc A. Dubé, Auteur Année de publication : 2010 Article en page(s) : pp. 7303–7312 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Adhesive  Properties Résumé : A one-pot, two-step miniemulsion polymerization approach was successfully used to create poly(2-ethyl hexyl acrylate/methyl methacrylate/acrylic acid) pressure sensitive adhesives with well-defined and predictable bimodal particle size distributions (PSDs) or bimodal molecular weight distributions (MWDs). The resulting viscoelastic (shear storage and loss moduli) and adhesive properties (i.e., loop tack, peel strength, and shear strength) were tested and compared to monomodal distributions of either particle size or molecular weight along with bimodal distributions created by postpolymerization blending. The results indicated that in situ bimodal MWDs offered superior values of PSA properties when compared to either monomodal MWDs or postpolymerization blends. Viscoelastic analysis of the in situ bimodal MWD samples showed that the proposed approach can effectively vary the MWDs and cross-linking densities of the resulting PSAs, thus tailoring the final properties. In comparison, the in situ bimodal PSD latexes did not show significant differences in viscoelastic behavior, but they exhibited large differences in PSA properties. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100204x [article] Effect of Bimodality on the Adhesive Properties of Pressure Sensitive Adhesives : Role of Bimodal Particle Size and Molecular Weight Distributions [texte imprimé] / Gabriela E. Fonseca, Auteur ; Timothy F. L. McKenna, Auteur ; Marc A. Dubé, Auteur . - 2010 . - pp. 7303–7312. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7303–7312 Mots-clés : Adhesive  Properties Résumé : A one-pot, two-step miniemulsion polymerization approach was successfully used to create poly(2-ethyl hexyl acrylate/methyl methacrylate/acrylic acid) pressure sensitive adhesives with well-defined and predictable bimodal particle size distributions (PSDs) or bimodal molecular weight distributions (MWDs). The resulting viscoelastic (shear storage and loss moduli) and adhesive properties (i.e., loop tack, peel strength, and shear strength) were tested and compared to monomodal distributions of either particle size or molecular weight along with bimodal distributions created by postpolymerization blending. The results indicated that in situ bimodal MWDs offered superior values of PSA properties when compared to either monomodal MWDs or postpolymerization blends. Viscoelastic analysis of the in situ bimodal MWD samples showed that the proposed approach can effectively vary the MWDs and cross-linking densities of the resulting PSAs, thus tailoring the final properties. In comparison, the in situ bimodal PSD latexes did not show significant differences in viscoelastic behavior, but they exhibited large differences in PSA properties. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100204x

Particle Formation in Vinyl Chloride Emulsion Polymerization. Experimental Study / Hugo M. Vale in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8107–8118 Titre : Particle Formation in Vinyl Chloride Emulsion Polymerization. Experimental Study Type de document : texte imprimé Auteurs : Hugo M. Vale, Auteur ; Timothy F. L. McKenna, Auteur Année de publication : 2008 Article en page(s) : p. 8107–8118 Note générale : Chemical engineering Langues : Anglais (eng) Résumé : Particle formation in vinyl chloride emulsion polymerization has been investigated by means of ab initio and seeded experiments. A series of ab initio polymerizations was run in order to obtain reliable data regarding the dependence of the particle number on the emulsifier (SDS and SDBS) concentration, as well as to analyze the effect of the initiator concentration, stirring rate, and monomer-to-water ratio upon the particle number and the polymerization kinetics. Seeded polymerizations carried out at different concentrations of seed latex and surfactant made it possible to quantitatively evaluate the influence of these factors on the onset and extent of secondary particle formation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715153 [article] Particle Formation in Vinyl Chloride Emulsion Polymerization. Experimental Study [texte imprimé] / Hugo M. Vale, Auteur ; Timothy F. L. McKenna, Auteur . - 2008 . - p. 8107–8118. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8107–8118 Résumé : Particle formation in vinyl chloride emulsion polymerization has been investigated by means of ab initio and seeded experiments. A series of ab initio polymerizations was run in order to obtain reliable data regarding the dependence of the particle number on the emulsifier (SDS and SDBS) concentration, as well as to analyze the effect of the initiator concentration, stirring rate, and monomer-to-water ratio upon the particle number and the polymerization kinetics. Seeded polymerizations carried out at different concentrations of seed latex and surfactant made it possible to quantitatively evaluate the influence of these factors on the onset and extent of secondary particle formation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715153

Particle formation in vinyl chloride emulsion polymerization / Hugo M. Vale in Industrial & engineering chemistry research, Vol. 48 N° 11 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5193–5210 Titre : Particle formation in vinyl chloride emulsion polymerization : reaction modeling Type de document : texte imprimé Auteurs : Hugo M. Vale, Auteur ; Timothy F. L. McKenna, Auteur Année de publication : 2009 Article en page(s) : pp. 5193–5210 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Particle  size  distribution  Vinyl  chloride  monomer  Polymerization Résumé : A mathematical model is developed to help quantify and improve our understanding of the formation of particles and the evolution of the particle size distribution (PSD) in the emulsion polymerization of vinyl chloride monomer (VCM). A special feature of the model is the computation of the coupled radical number and particle size distributions by means of the zero−one−two population balance equations. This approach is shown to be necessary when modeling processes that involve particle nucleation. Preliminary results are presented to illustrate the ability of the model in interpreting experimental data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801406n [article] Particle formation in vinyl chloride emulsion polymerization : reaction modeling [texte imprimé] / Hugo M. Vale, Auteur ; Timothy F. L. McKenna, Auteur . - 2009 . - pp. 5193–5210. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5193–5210 Mots-clés : Particle  size  distribution  Vinyl  chloride  monomer  Polymerization Résumé : A mathematical model is developed to help quantify and improve our understanding of the formation of particles and the evolution of the particle size distribution (PSD) in the emulsion polymerization of vinyl chloride monomer (VCM). A special feature of the model is the computation of the coupled radical number and particle size distributions by means of the zero−one−two population balance equations. This approach is shown to be necessary when modeling processes that involve particle nucleation. Preliminary results are presented to illustrate the ability of the model in interpreting experimental data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801406n