Discussion of Measured SAXS Patterns

Unstrained materials. Before the start of the tests (s = 0) all the injection molded materials exhibit discrete SAXS with high uniaxial orientation. Two-point patterns are observed. The peak maxima are on the vertical axis (S3, meridian, direction of the melt-flow in the bar, straining direction). From top to bottom both the peak intensity and the lateral peak width are strongly increasing. The narrow reflections of the pure PP (top) and of the blend PP+MMT (below) are indicative for layer stacks made from crystalline lamellae in the PP that extend in the direction perpendicular to the direction of melt-flow. Nevertheless, the blend already contains an additional background. It is a broad peak underneath the narrow reflection, which indicates an additional microfibrillar component. In this component the shape of the crystalline domains is no longer an extended lamella, but only a granule of lower lateral extension. 

The blend and the composites exhibit strong central scattering of big scattering entities. These entities may either be crazes formed between the nanoparticles and the PP matrix, or bigger particles of MMT that have not been exfoliated. Typical for craze scattering is diffuse central scattering showing an envelope of cross shape or of diamond shape [40 5]. 

PP/MMT blend and nanocomposites. The scattering patterns of the blend and the two nanocomposites are presented in rows 2-4 of Fig. 5.3. All materials show the mentioned transition into a microfibrillar stack morphology, but their initial stmcture is different from the initial structure of the pure PP. The scattering patterns appear rather blurred and a direct qualitative interpretation can only describe very general 

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