Polymer networks are widely studied materials; their especial properties allow them to be applied in areas such as the fertilizer industry, medicine, biochemistry, chemical analysis among others. In general, the polymer network microstructure has influence in macroscopic properties of materials, hence the interest of such microstructure in final properties are of strategic interest. The cyclization reactions influence in the microstructure control of polymer networks. It is known that an increase in system's dilution can increase the cyclization reactions incidence. Mathematical modeling of copolymerization of styrene-divinylbenzene is a widely studied subject, but few studies have been conducted considering the cyclization reactions with a defined kinetic and not a problem black-box type. This work aimed to study the styrene-divinylbenzene copolymerization solutions and their mathematical modeling with the inclusion of intramolecular cyclization reactions. Thus, solution copolymerization of styrene and divinylbenzene was carried out at low concentration of monomers in batch reactor. Two mathematical models were initially used to analize the behavior of the system, which were called: Model A and Model B. The Model A was developed by molar balance of species in the reaction medium and includes cyclization reactions, which were considered to happen in polymer chains with 300 or less monomer units. Due the dilution was believed that this number of units covering all sizes of dead polymers, but comparison between Model A an experimental data proved otherwise. The Model B was based in model of Aguiar (2013), and uses the mass balance for non-polimerics species and moments methods for polimerics species. Model B also uses numerical fractionation for average molecular weight and gel point determination, and the method of paths to approach cyclization reactions. When compared to experimental data, Model B proved more realistic, presenting shorter simulation times and less numerical problems than Model A. Therefore Model B was chosen to represent the system. The results presented by Model B indicate that the parameter assigned to the kinetics os crosslink (Cp) was fitted at 0,05 and cyclization rate constant for paths with 3 monomer units was fitted 130 s -1 at temperature of 90°C. The cyclization rate constants for longer paths were calculated trough Rolfes and Stepto's equation. This work is a follow up to Aguiar's work (2013) and the results showed that the simulation of variables: concentration of pendant double bonds, average molecular weight and polidispersity better predicted when the cyclization rate constants are greater than zero.

AGRADECIMENTOS À minha família: Valter (Valtinho), Elineuza (Zita) e Tauane, sem vocês nada disso teria se realizado, muito obrigado pelo apoio, compreensão e companheirismo. Ao professor Reinaldo Giudici por ser um exemplo de profissional com todo o seu conhecimento, apoio, direcionamento e compreensão que tanto contribuiu para a minha formação acadêmica Ao meu coorientador e amigo Dr. Leandro Aguiar pela excelente coorientação, paciência, dedicação, apoio, compreensão e contribuição nesse trabalho e em minha formação acadêmica. Aos companheiros e amigos do grupo de polímeros do professor Reinaldo: Giuliana, Esmar, Paula, Nathália, Magda e Narjara por sempre ajudarem e por tornar agradáveis os momentos de trabalho. Aos amigos, professores e funcionários do Departamento de Engenharia Química da Escola Politécnica da USP pela amizade. Aos meus familiares pelo apoio e incentivo durante esta etapa. Ao programa de Pós Graduação em Engenharia Química e à CNPQ pelo auxílio financeiro durante grande parte do desenvolvimento desse trabalho EPÍGRAFE "A luta pela verdade deve ter precedência sobre todas as outras" (Albert Einstein) RESUMO SANTOS, V. N. Estudo da formação de redes poliméricas através da técnica de polimerização em miniemulsão: Estudo Experimental e Modelagem Matemática. Tese (Doutorado em Engenharia Química -