Compósitos obtidos a partirde polipropileno e muscovita ultrassonicada

Abstract

Composites based on polymers and phyllosilicate minerals are well-known systems with many of their properties and application potential well documented in the literature. However, these systems usually require additives and/or chemical treatments of the mineral to improve matrix/filler adhesion. Particularly for muscovite mica, there are cations and hydroxyls between its lamellas, so that their delamination could contribute to improving the interaction in polymer/mineral systems. In this context, this work aimed to study the influence of ultrasonic treatment of muscovite on obtaining composites with polypropylene (PP). Muscovite (-125µm) was treated ultrasonically for 60 and 120 minutes and used to obtain composites with the polymer (PP, PP/Mica125, PP/Mica125US60 and PP/Mica125US120), with a mineral content of 15%. The samples were processed in a single-screw extruder, followed by grinding and conforming into films. The particle size distribution and SEM obtained for the ultrasonicated micas revealed an increase in delamination and a decrease in particle size with increasing treatment time. The characterization of the composites in terms of density showed an increase in that property with an increase in ultrasonic treatment time, which suggests an improvement in the interaction with the polymer. The SEM of the composites revealed a more homogeneous distribution and greater alignment of the mineral for the ultrasonically treated samples. The IZOD impact results suggested increased crystallinity for the PP/Mica125US120 sample. FTIR indicated that the nature of the polymer/mineral interaction was not altered by ultrasonic treatment. However, XRD revealed a shift in the position of some mica peaks in the composites, regardless of ultrasonication, which may indicate intercalation of the mineral by the polymer chains. The general analysis of the results shows that the ultrasonic treatment is effective in delaminating the muscovite and improving the interaction with the polymer, with better results being observed for the PP/Mica125US120 sample.