This work describes the preparation of composites of polypropylene and organophilic bentonites based on Brazilian and Argentinean bentonites. During the processing of the samples in a twin screw microextruder, torque and pressures of the extruder were accompanied and the viscosity values were calculated. No significant changes in the torque, pressure and viscosity were found for composites prepared with different bentonites. The samples were characterized by XRD and TEM to evaluate the structure and dispersion of the organophilic bentonites. Composites with exfoliated, partially exfoliated and intercalated structures were obtained and correlations between the intrinsic properties of the sodium clays and organophilic bentonites and their influence on the composites were studied. The cation exchange capacity of the sodium bentonites and the swelling capacity of the organophilic bentonites were the most important properties to obtain exfoliated structures in composites. All bentonites showed the potential to obtain polymer nanocomposites, but the ones from Argentina displayed the best results.

This study describes the influence of the intrinsic properties of raw materials on the organophilization of bentonites from Argentinean raw sodium bentonites and Brazilian sodium activated bentonites. The organophilization was done with two methodologies: solid-liquid and semisolid reactions. Correlations between the properties of sodium and organophilic bentonites were established. The effectiveness of the treatments was verified by X-ray diffraction, swelling capacity in water and xylene and SEM to evaluate the morphology of the particles. The analysis was done before and after the modification process. The bentonites had organic cations intercalated, as shown by the increase of the basal spacings, and the organophilic character was confirmed because the bentonites showed xylene swelling capacity and particles with an expanded aspect in comparison to those of the sodium bentonites. Both methodologies were efficient to obtain organophilic clays. The organophilic bentonites obtained from raw sodium bentonites gave better results.

As argilas são materiais muito usados e que atualmente apresentam inúmeras aplicações devido as interessantes propriedades que apresentam. A modificação superficial de argilas é uma área que tem recebido bastante atenção dos pesquisadores porque por meio dos diversos tipos de modificação é possível a preparação de novos materiais e novas aplicações. Este trabalho tem como objetivo apresentar uma revisão bibliográfica sobre argilas organofílicas, especialmente as obtidas a partir de bentonitas e de sais quaternários de amônio. Diversos estudos vêm sendo realizados baseados em diferentes técnicas e parâmetros de síntese desses materiais, incluindo argilas de diferentes regiões e diferentes agentes de modificação, bem como as diferentes aplicações que são propostas.

Clays are materials used since historical periods and nowadays have several applications due to their interesting properties. The surface modification of clays is one area that has received enough attention from researchers because through modification it is possible to prepare new materials and find applications. The purpose of this paper is to present a review on the use of clays for obtaining organophilic clays, especially those used in polymeric nanocomposites. Several studies have been done based on different techniques and process conditions of these materials. The review includes clays of different regions, different modification agents and applications.