Palygorskite (Pal) is a natural clay mineral with fibrous morphology and high surface area. Depending on the geological origin, it presents impurities, such as quartz and carbonates, which can harm some of its properties. Therefore, this work seeks to define a viable methodology for the purification of a Brazilian Pal. Two types of mixing processes (sonication and milling) and two types of dispersing agents (sodium silicate and sodium polyacrylate) were investigated. In addition, a subsequent acid activation with hydrogen peroxide and sulfuric acid was performed for complete purification. The viability of the purification of Pal was confirmed by X-ray diffraction, X-ray fluorescence, and thermogravimetric analyses. The sonication mixture process and the use of sodium polyacrylate as a dispersing agent were more effective. In addition, BET analysis showed an increase in the surface area of Pal, and scanning electron microscopy confirmed the permanence of its fibrous morphology after the purification steps.

No abstract

No abstract

The development of polymeric nanocomposites using clay minerals as a Nano filler is of great interest to researchers and industry. Many clay minerals are used to modify the properties of the polymers; this strategy improves the thermal and mechanical performance and changes the surface finishing and the processing characteristics. The Attapulgite (ATP), which is a clay mineral of the hydrated magnesium silicates family, has gained prominence in recent years because it combines low cost and high performance. It has a large surface area, strong absorption capacity superior to any other natural mineral, good mechanical resistance and thermal stability. These properties make ATP an ideal candidate for reinforcing polymeric materials. Different approaches and emerging technologies have been applied to improve the thermal and mechanical properties of polymer/ATP nanocomposites which can extend the different chemical treatments used in ATP. Therefore, this review article presents the latest advances related to the use of ATP in the development of polymeric nanocomposites, showing future perspectives for new trends in ATP applications. In general, ATP modifies the mechanical properties of polymers, either in the natural or modified state. And is a good alternative for the replacement of lamellar clays such as montmorillonites with the advantage of having a lower cost and a wide world market to be explored, that which drive new trends in applications for ATP, such as flame retardant of cotton fabrics, dye adsorption, hydrogel membranes for wound dressing, sustainable packaging and fuel cell applications.

Resumo obilidade e segurança são temas cada vez mais discutidos nos grandes centros urbanos, e as iniciativas nesse universo devem prever soluções práticas e econômicas, que gerem benefícios para os cidadãos. O pavimento, um dos fatores para a qualidade urbana, é a via de acesso indispensável para garantir o direito de ir e vir. Entre as soluções, o pavimento intertravado se destaca como um dos produtos mais recomendados na pavimentação das calçadas e áreas públicas. Em países da Europa e da América Latina a pavimentação com sistemas intertravados de cerâmicas é amplamente utilizada, porém essa prática ainda é pouco observada no Brasil, pela inexistência desse produto no mercado local. Desse modo, o objetivo deste projeto foi o desenvolvimento de pavimentos intertravados de cerâmica visando ao uso em passeios e áreas públicas. Também foram adicionados ao novo produto desenvolvido resíduos queimados oriundos do próprio processo de fabricação, os quais são chamados de cacos ou chamote, para diminuir a quantidade de material a ser descartado no meio ambiente. Após os resultados positivos na caracterização dos produtos, foram criados novos designs para essa tipologia de produtos, os quais foram produzidos em escala laboratorial. Ambiente Construído, Porto Alegre, v. 16, n. 4, p. 155-165, out./dez. 2016. Dias, L. L.; Menegazzo, A. P. M.; Quinteiro, E.; Serafim, M. A. Palavras