The work presented herein focuses on expanding the use of CO2-triggered switchable surfactants in emulsion polymerization of hydrophobic and hydrophilic monomers. Bicarbonate salts of the following compounds were employed as surfactants in the emulsion polymerization of styrene, methyl methacrylate (MMA) and/or butyl methacrylate (BMA): N’-hexadecyl-N,N-dimethylacetamidine (1a), N’-dodecyl N,N-dimethylacetamidine (2a) and N’-(4-decylphenyl)-N,N-dimethylacetamidine (3a). A systematic study of the effects of surfactant and initiator concentrations and solids content on the resulting particle size and ζ-potential was carried out, showing that a wide range of particle sizes (40 – 470 nm) can be obtained. It was found that as the basicity of the surfactant decreased, the particle size generated from emulsion polymerization increased. Destabilization of these latexes did not require the addition of salts and was carried out using only non-acidic gases and heat. It was shown that solids content, temperature, particle size and surfactant basicity greatly affect the rate of destabilization of latexes. The area occupied by N’-dodecyl-N,N-dimethylacetamidinium acetate on PMMA particles was determined to be 104 Å2. The monomer-D2O partition coefficient of 2a was determined to be 21 for styrene and 2.2 for MMA. The monomer-D2O partition coefficient of the bicarbonate salt of 2a was determined to be 1.2 for styrene and 0.85 for MMA. An initial assessment of the use of switchable surfactants in the generation of inverse emulsions was carried out. It was determined that butylated polyethyleneimine (BPEI) can successfully stabilize inverse emulsions of cyclohexane and aqueous 2-(dimethylamino)ethyl methacrylate. Upon CO2 introduction, this emulsion separates into two distinct phases. / Thesis (Master, Chemistry) -- Queen's University, 2011-09-26 11:10:14.053

Experimental data on the solubility of CO2 in methyl methacrylate (MMA) and butyl methacrylate (BMA) are reported at temperatures from 308 to 333 K and pressures in the range of 1 to 10 MPa. The corresponding measurements of the volumetric expansion of the liquid phase are also presented. The solubility data are correlated with the Peng-Robinson equation of state using two interaction parameters. Solubilities of CO2 as high as 80 mol% can be attained in both monomers in the range of pressure considered. A near-linear relationship is observed between pressure and liquid-phase composition. The Peng-Robinson equation of state provides a satisfactory correlation of the solubility data. The average absolute relative deviations with respect to the calculated values of pressure are less than 2%. For a given monomer, the expansion isotherms coincide when plotted as a function of the liquid - phase composition. Catalytic chain transfer (CCT) polymerisation of CO2-expanded MMA, BMA and styrene is then described. Experimental values of the chain transfer constant are determined at 323 K and 333 K and in the range of pressure from 0.1 to 6 MPa. A cobaloxime complex is used as the chain transfer catalyst. The effect of small quantities of polymer on the volumetric expansion of the corresponding monomer is considered. The chain transfer constants for the expanded monomers are significantly higher than those obtained in the bulk monomers. It is demonstrated that a linear relationship exists between the chain transfer rate coefficient and the inverse of liquid-phase viscosity. These results provide significant evidence that the rate-determining step in the CCT process is diffusion-controlled. Finally, molecular weight evolution in CCT polymerization of CO2-expanded MMA is reported. Experimental molecular weight and polydispersity index data are presented at 323 K in the range of conversion from 1 to 25%, and at pressures of 5 and 6 MPa. Both molecular weight and polydispersity increase with conversion at conditions below the homogeneous expansion limit. Predici simulations suggest that either irreversible catalyst deactivation or cobalt-carbon bond formation is the most likely mechanism for the increase in molecular weight with conversion.

Orientador: Leila Peres / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-26T22:00:36Z (GMT). No. of bitstreams: 1 Lucente_AnaGlauciaBogalhos_D.pdf: 2114033 bytes, checksum: ddc1d7f9bcfcce3f7ddfd258b22465d3 (MD5) Previous issue date: 2015 / Resumo: A falta de um material que viabilize a confecção de uma prótese dentária em um menor número de etapas, economizando tempo e facilitando a vida dos pacientes foi a maior motivação para o desenvolvimento desta tese que se baseia na patente BR n. PI 0602107-7 A: Conjuntos de arcos dentais pré-fabricados, flexíveis e com dentes ajustáveis obtida pelo grupo de pesquisa onde se insere este trabalho, em que se propõe o uso do arco dental flexível pré-fabricado na confecção da prótese, que poderá ser produzida em um menor tempo, com um menor custo. O material usado para o arco dental flexível pré-fabricado por energia de micro ondas, bem como para a prótese dental final deverá conter uma base polimérica que permitirá a flexibilidade inicial do arco, que após receber ajustes na posição dos dentes, adequados a cada paciente, será incorporado à prótese final, sendo o conjunto reticulado de forma simultânea. Para tanto, foi investigada a viabilidade do uso do copolímero de metacrilato de metila-n-metacrilato de butila (PMMA-co-PBMA), sintetizado via técnica de miniemulsão, como a matriz polimérica base para a confecção de arcos dentais pré-fabricados, flexíveis e com dentes ajustáveis e da prótese final. Na síntese do copolímero pretendido, foram estudadas as características dos iniciadores, surfactante, estabilizador e temperatura de reação sobre a distribuição volumétrica (Dv) e populacional (DSD) de tamanhos de partícula, conversão global, temperatura de transição vítrea (Tg), massa molar média ponderal (Mw), massa molar média numérica (Mn) e polidispersividade (Mw/Mn). Verificou-se a influência da solubilidade dos iniciadores em baixas temperaturas na conversão global, Dv e DSD, fator que não interfere em altas temperaturas. Além das análises de Tg, Mw e Mw/Mn dos copolímeros e homopolímeros obtidos por mecanismo de adição. Realizaram-se também análises de Ressonância Magnética Nuclear (RMN) e Espectroscopia no Infravermelho com Transformada de Fourrier (FT-IR) indicando que o copolímero foi formado na configuração alternada ou aleatória. A resina formulada a partir do copolímero sintetizado para uso no arco dental pré-fabricado foi caracterizado, a partir de ensaios de resistência à flexão, microdureza, módulo de elasticidade, coeficiente de Poisson, da Tg do material e monômero residual. Os resultados mostram um material compatível com resinas comerciais em relação à microdureza e módulo de elasticidade / Abstract: The lack of a material that enables the production of a dental prosthesis in fewer steps, saving time and making life easier for the patients was the major motivation for developing this thesis is based on the patent BR n. PI 0602107-7 A: Sets of prefabricated dental arches, flexible and adjustable teeth obtained by the research group which includes this work, it is proposed the use of prefabricated flexible dental arch in the making of the prosthesis, which can be produced in less time, with less cost. The material used for the flexible prefabricated dental arch by microwave energy and for the final dental prosthesis should contain a polymer base which will allow the initial flexibility of the arch, after receiving adjustments to the position of the teeth, adequate to each patient will be incorporated into the final prosthesis being crosslinked together simultaneously. Therefore, it was investigated the feasibility of using n-butyl methyl methacrylate-methacrylate copolymer (PMMA-co-PBMA) synthesized via miniemulsion technique as the base polymer matrix for the manufacture of prefabricated dental arches, flexible and adjustable teeth and the final prosthesis. In the synthesis of the desired copolymer characteristics of primers were studied, surfactant, stabilizer and reaction temperature on the size distribution (Dv) and population (DSD) particle size, overall conversion, glass transition temperature (Tg), mass-average molecular weight (Mw), number-average molecular weight (Mn) and polydispersity (Mw/Mn). It has been found to influence the solubility of the initiators at low temperatures in the overall conversion, Dv and DSD factor that does not interfere at high temperatures. In addition to the analyzes Tg, Mw and Mw / Mn of the copolymers and homopolymers obtained by adding mechanism. Nuclear Magnetic Resonance analysis (NMR) spectroscopy and Fourier transform infrared (FT-IR) were also performed indicating that the copolymer was formed in alternating or random configuration. The resin made from copolymer synthesized for use in prefabricated dental arch was characterized as bending strength tests, hardness, modulus of elasticity, Poisson's ratio, the Tg of the material and residual monomer. The results show a material similar to commercial resins with regard to hardness and modulus of elasticity / Doutorado / Ciencia e Tecnologia de Materiais / Doutora em Engenharia Quimica