Utilização de concentrados de eva-argila organofílica obtidos por spray drying, drais e extrusão no desenvolvimento de nanocompósitos poliméricos
Bernardo, Paulo Rodrigo Alves
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The objective of this work was the development of polymer nanocomposites with montmorillonite organoclays (OMMT) using EVA-OMMT concentrated obtained by spray drying, Drais and extrusion, making the characterization and correlation with the thermal, dynamic mechanical and gas transport properties. LLDPE nanocomposites films were obtained by incorporating the EVA-OMMT powders concentrates. The XRD results showed that the concentrated powders for the spray drying process the shift to smaller angles is more effective for 19% VA and for processing by Drais only 8.5% VA. As for processing by Drais, it was possible to incorporate large amounts of clay, but the results of dispersion and intercalation depends on the use of modified clay and compatible with the matrix used. For processing by spray drying, it showed to be very efficient in incorporation of large amounts of clay in EVA matrix. In the TEM analysis for spray drying powder concentrate, it was observed that, with the increase of MFI of LLDPE matrix and increased of %VA, the areas where the clay is present showed an increase of its dimension and may facilitate the process of intercalation and clay dispersed in the matrix. The permeability results showed a competition between the increased permeability due to a reduction of the crystallinity and, at the same time, reduced permeability due to the higher clay amount in the matrix, since that the clay is properly dispersed. The results showed that the spray drying process is an innovative way to obtain EVA/OMMT concentrated powder with high clay content. The nanocomposite powder with EVA/OMMT 3:1 weight ratio and 7wt% OMMT showed an intercalalated structure and evidence of exfoliation, with 38% oxygen permeability reduction.