Deformation mechanisms of polypropylene/polystyrene multilayered films

Abstract

Multilayered composites of polypropylene (PP) and polystyrene (PS) fabricated by a layer-multiplying coextrusion technique are described. The aim of this investigation was to find a correlation between the morphology and the mechanical and micromechanical deformation behavior. The multilayered films had primarily continuous layers, exhibiting only few defects in layer construction and turning into an irregularly layered system when the calculated layer thickness was only 5 nm. The morphology and layer thickness of both the PP and PS layers affected the mechanical and the micromechanical behavior, which was brittle for the films having PS layers thicker than 75 nm and ductile when the PS layers were 50 nm and thinner. Transmission electron microscopy showed crazes in the thicker PS layers and homogeneous deformation in the thinner ones. The molecular orientation during deformation of the ductile films was calculated from rheo-optical measurements with Fourier transform infrared spectroscopy. V C 2012 Wiley Periodicals, Inc. J Appl

Influence of laminate thickness reduction on the deformation mechanism of coextruded multilayered PC/PMMA films

“…It is much higher than the value reached with the multilayered film having a single layer thickness of about 12 nm (strain rate 100%). Similar results could be found for the multilayered system polypropylene/PS 17. The elongation at break of the multilayered films increased by decreasing the layer thickness and elongation at break was much higher than that of brittle bulk PS.…”