Molecular dynamics simulations of surfactants' adsorption in emulsion polymerizations and of CO2 capture by graphene-polymer composites.

302 p.Adsorption is an increase in the concentration of a dissolved substance at the interface of a solid and a liquid phase due to the operation of surface forces. Adsorption has emerged as an important process for various industrial applications, such as emulsion polymerization and gas separation. Surfactants have a crucial role in emulsion polymerization due to their inward properties; namely, they affect the polymer particles nucleation and prevent them from the coagulation by the reduction of surface tension. However, many aspects of their use are poorly understood and cause significant problems. In this thesis the combination of experimental and computational studies will be reported with the aim to elucidate the adsorption properties of ionic and non-ionic surfactants on hydrophobic polymer surface such as poly(styrene). Also, since the particle nucleation behavior of nonionic surfactants exhibits deviations from the Smith-Ewart model, which described the kinetic mechanism of the particle nucleation typical for ionic surfactant, we seek to take a deeper look of the behavior of these two classes of surfactants at monomer/polymer-water interface during the emulsion polymerization of styrene. Three-dimensional graphene-polymer porous materials have been proposed recently as potential adsorbents for carbon dioxide capture. Owing to their mechanical stability and ease of regeneration they can potentially alleviate short- coming encountered by other sorbents. Molecular dynamics simulation will be performed to study the adsorption of carbon dioxide by different graphene-polymer composite systems. Additionally an estimation of the CO2 selectivity respect to N2 and CH4 will be examined to prove the ability of the composite materials to discriminate against these competing gasses.Polyma

Molecular dynamics simulations of surfactants' adsorption in emulsion polymerizations and of CO2 capture by graphene-polymer composites.

302 p.Adsorption is an increase in the concentration of a dissolved substance at the interface of a solid and a liquid phase due to the operation of surface forces. Adsorption has emerged as an important process for various industrial applications, such as emulsion polymerization and gas separation. Surfactants have a crucial role in emulsion polymerization due to their inward properties; namely, they affect the polymer particles nucleation and prevent them from the coagulation by the reduction of surface tension. However, many aspects of their use are poorly understood and cause significant problems. In this thesis the combination of experimental and computational studies will be reported with the aim to elucidate the adsorption properties of ionic and non-ionic surfactants on hydrophobic polymer surface such as poly(styrene). Also, since the particle nucleation behavior of nonionic surfactants exhibits deviations from the Smith-Ewart model, which described the kinetic mechanism of the particle nucleation typical for ionic surfactant, we seek to take a deeper look of the behavior of these two classes of surfactants at monomer/polymer-water interface during the emulsion polymerization of styrene. Three-dimensional graphene-polymer porous materials have been proposed recently as potential adsorbents for carbon dioxide capture. Owing to their mechanical stability and ease of regeneration they can potentially alleviate short- coming encountered by other sorbents. Molecular dynamics simulation will be performed to study the adsorption of carbon dioxide by different graphene-polymer composite systems. Additionally an estimation of the CO2 selectivity respect to N2 and CH4 will be examined to prove the ability of the composite materials to discriminate against these competing gasses.Polyma

Molecular dynamics simulations of surfactants'adsorption in emulsion polymerizations and of CO2 capture by graphene-polymer composites.

302 p.Adsorption is an increase in the concentration of a dissolved substance at the interface of a solid and a liquid phase due to the operation of surface forces. Adsorption has emerged as an important process for various industrial applications, such as emulsion polymerization and gas separation. Surfactants have a crucial role in emulsion polymerization due to their inward properties; namely, they affect the polymer particles nucleation and prevent them from the coagulation by the reduction of surface tension. However, many aspects of their use are poorly understood and cause significant problems. In this thesis the combination of experimental and computational studies will be reported with the aim to elucidate the adsorption properties of ionic and non-ionic surfactants on hydrophobic polymer surface such as poly(styrene). Also, since the particle nucleation behavior of nonionic surfactants exhibits deviations from the Smith-Ewart model, which described the kinetic mechanism of the particle nucleation typical for ionic surfactant, we seek to take a deeper look of the behavior of these two classes of surfactants at monomer/polymer-water interface during the emulsion polymerization of styrene. Three-dimensional graphene-polymer porous materials have been proposed recently as potential adsorbents for carbon dioxide capture. Owing to their mechanical stability and ease of regeneration they can potentially alleviate short- coming encountered by other sorbents. Molecular dynamics simulation will be performed to study the adsorption of carbon dioxide by different graphene-polymer composite systems. Additionally an estimation of the CO2 selectivity respect to N2 and CH4 will be examined to prove the ability of the composite materials to discriminate against these competing gasses.Polyma

Mechanism of the suzuki-miyaura cross-coupling reaction mediated by [Pd(NHC)(allyl)Cl] Precatalysts

Density functional theory calculations have been used to investigate the activation mechanism for the precatalyst series [Pd]-X-1-4 derived from [Pd(IPr)(R-allyl)X] species by substitutions at the terminal position of the allyl moiety ([Pd] = Pd(IPr); R = H (1), Me (2), gem-Me2 (3), Ph (4), X = Cl, Br). Next, we have investigated the Suzuki-Miyaura cross-coupling reaction for the active catalyst species IPr-Pd(0) using 4-chlorotoluene and phenylboronic acid as substrates and isopropyl alcohol as a solvent. Our theoretical findings predict an upper barrier trend, corresponding to the activation mechanism for the [Pd]-Cl-1-4 series, in good agreement with the experiments. They indeed provide a quantitative explanation of the low yield (12%) displayed by [Pd]-Cl-1 species (G 30.0 kcal/mol) and of the high yields (90%) observed in the case of [Pd]-Cl-2-4 complexes (G 20.0 kcal/mol). Additionally, the studied Suzuki-Miyaura reaction involving the IPr-Pd(0) species is calculated to be thermodynamically favorable and kinetically facile. Similar investigations for the [Pd]-Br-1-4 series, derived from [Pd(IPr)(R-allyl)Br], indicate that the oxidative addition step for IPr-Pd(0)-mediated catalysis with 4-bromotoluene is kinetically more favored than that with 4-chlorotoluene. Finally, we have explored the potential of Ni-based complexes [Ni((IPr)(R-allyl)X] (X = Cl, Br) as Suzuki-Miyaura reaction catalysts. Apart from a less endergonic reaction energy profile for both precatalyst activation and catalytic cycle, a steep increase in the predicted upper energy barriers (by 2.0-15.0 kcal/mol) is calculated in the activation mechanism for the [Ni]-X-1-4 series compared to the [Pd]-X-1-4 series. Overall, these results suggest that Ni-based precatalysts are expected to be less active than the Pd-based precatalysts for the studied Suzuki-Miyaura reaction