Production of geopolymeric microspheres by reaction in suspension gelatin medium

Introduction: Geopolymers are supplemental alkali activated cementitious materials which, when in alkaline solution, harden due to polymerization. In 1972, Davidovits named geopolymers as three-dimensional aluminosilicates formed rapidly at low temperatures by naturally occurring aluminosilicates. Activation efficiency depends on the chemical and mineralogical composition of the raw materials, which are rich in silica and alumina. Geopolymerizations are processes and transformations of sources rich in aluminum oxides and silica in binder materials, with characteristics similar to hydrated Portland cement. It is already known that satisfactory levels of mechanical strength can be obtained depending on the chemical composition of the materials and the curing conditions (1). This work describes a simple and effective process for fabricating porous metakaolin-based inorganic polymer microspheres. The process for making porous geopolymer spheres by a suspension and solidification was experimentally established, for this were used a solution at 6 M of sodium hydroxide and sodium silicate, the reaction was performed for 5 minutes. After, 9 grams of metakaolin was added to the alkaline solution and was stirring for 10 minutes. After this period 0.5% w/w of the porosity agent hydrogen peroxide (H2O2) and 0.3% w/w of the Sodium Lauryl Sulfate was added and the mechanical stirring occurred for 5 minutes. The mixture obtained was dropped with the syringe on 50 mL of gelatin and heated at 100°C. The microspheres obtained were collected and washed. The production of microspheres had a yield of 12 grams of the microspheres. The microspheres were suspended in gelatin medium. The scanning electron microscopy (SEM) showed that it was possible to form the microspheres and the size was 350µm. Key words: Geopolymers, Microspheres, Gelatin Acknowledgement: The authors thank to Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), Financiadora de Estudos e Projetos (FINEP PRESAL Ref.1889/10) and Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ) for the financial support and scholarships. References [1] VASSALO, Erica. Obtencao de geopolimero a partir de metacaulim ativado. 2013.18p. Dissertacao apresentada ao programa de pos Graduacao em construcao civil da Universidade Federal de Minas Gerais, 2013.