NMR evaluation of polystyrene nanocomposites degradated by repeated extrusion processing

Polystyrene nanocomposites with organoclay were prepared by melt extrusion in a twin screw extruder. After that, the samples were submitted to several cycles in the extruder to degrade them. The materials obtained before and after degradation cycles were analyzed by melt flow index measurements, X-ray diffraction and principally by nuclear magnetic resonance spectroscopy. The results showed the formation of nanomaterials with good dispersion and distribution containing low nanoparticle concentration and the nanostructured materials formed presented mixed morphology, composed of intercalated and exfoliated structures. The use of NMR spectroscopy allowed obtaining information on sample degradation with the increase of cycle times through the loss of structural organization and changes in the molecular dynamics of the materials through the T1H relaxation data. All the results shed light on the behavior of the degradation process in the materials formed. (C) 2015 Elsevier Ltd. All rights reserved.