The development of polymer nanocomposites has been an area of high scientific and industrial interest in the recent years, due to several improvements achieved in these materials, as a result of the combination of a polymeric matrix and, usually, an inorganic nanomaterial. The improved performance of those materials can include mechanical strength, toughness and stiffness, electrical and thermal conductivity, superior flame retardancy and higher barrier to moisture and gases. Nanocomposites can also show unique design possibilities, which offer excellent advantages in creating functional materials with desired properties for specific applications. The possibility of using natural resources and the fact of being environmentally friendly have also offered new opportunities for applications. This chapter aims to review the main topics and recent progresses related to polymer nanocomposites, such as techniques of characterization, methods of production, structures, compatibilization and applications. First, the most important concepts about nanocomposites will be presented. Additionally, an approach on the different types of filler that can be used as reinforcement in polymeric matrices will be made. After that, sections about methods of production and structures of nanocomposites will be detailed. Finally, some properties and potential applications that have been achieved in polymer nanocomposites will be highlighted.

A bentonita, composta predominantemente pelo argilomineral montmorilonita que lhe confere as propriedades físicas concentra a maior parte das reservas nacionais (62%) no Estado da Paraíba. A transformação da bentonita em argila organofílica consiste em um procedimento laboratorial simples e pode ser realizada através de reação de troca dos cátions (Na+ ou Ca2+) presentes na superfície e no espaço interlamelar dos argilominerais, por cátions de sais quaternários de amônio. Neste trabalho as bentonitas organofílicas foram preparadas utilizando quatro tipos diferentes de sais quaternários de amônio, tais como: cloreto de alquil dimetil benzil amônio (Dodigen), cloreto de estearil dimetil amônio (Praepagen), cloreto de cetil trimetil amônio (Genamin) e brometo de cetil trimetil amônio (Cetremide). As argilas organofilizadas foram caracterizadas por termogravimetria, difração de raios X, análise química e por fluorescência de raios X. Os resultados confirmaram a incorporação dos sais quaternários de amônio na estrutura da argila e mostraram que dois dos quatro sais quaternários utilizados, o Praepagen e o Cetremide apresentaram uma faixa maior de estabilidade térmica.