Utilização de polímero pós-consumo sulfonado como aditivo de sistemas cimentícios

• Ano de defesa: 2012
• Autor(a) principal: Souza, Thaís dos Santos
• Orientador(a): Munhoz Junior, Antonio Hortêncio
• Banca de defesa: Miranda, Leila Figueiredo de , Diaz, Francisco Rolando Valenzuela
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Presbiteriana Mackenzie
• Programa de Pós-Graduação: Engenharia de Materiais
• Departamento: Engenharia de Materiais
• País: BR
• Palavras-chave em Português: aditivos; dispersantes; polieletrólitos; sistema cimentícios; sulfonação; EPS
• Palavras-chave em Inglês: admixtures; dispersants; polyelectrolytes; cementitious systems; sulfonation; EPS.
• Área do conhecimento CNPq: CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA
• Link de acesso: http://dspace.mackenzie.br/handle/10899/24158

The suitable superplasticizers admixtures usage has become fundamental in the cementitious systems production (like concretes and mortars), because they interact with cement particles surfaces, causing their dispersion and deflocculation without the excessive water addition. The hardened material with a smaller water quantity acquires better positive, like higher compressive strength, lower permeability and extended durability. The major dispersants admixtures are negative charged polymers (polyelectrolytes) that are capable to adsorb on the cement particles and cause their electrostatic dispersion. Given the current environmental and economic interest in reuse of discarded materials, the purpose of this study was to assess the viability of use and application of modified post-consumer expanded polystyrene (EPS) as an admixture to cementitious systems becoming it a higher added value material. The modification of the EPS was performed by sulfonation and the interfering variables in the reaction were evaluated. The performance of the stabilized polyelectrolyte already formed (sodium polystyrene sulfonate NaPSS) as dispersant was verified in cement paste and mortar. The study showed that modification of post-consumer EPS by sulfonation reaction was carried out efficiently regarding to the production of a polyelectrolyte with a maximum degree of modification, within the conditions studied, and which variables most influence the reaction. Moreover, the product with a maximum degree of modification (most likely to interact with the cement) was not effective as a dispersant for cementitious systems, causing a decrease in the mechanical strength and plasticity evaluated.