Evaluation of preferred orientation in multi-component polymer systems using x-ray scattering procedures

Abstract

A new approach is presented for the decomposition of anisotropic x-ray scattering patterns from oriented multi-component samples into the scattering from each component. The method is based on the representation of an anisotropic scattering pattern by an orthogonal series of spherical harmonic functions. These functions may be written as the linear combination of the equivalent functions from the pure samples. This provides a route to separate the data from the multi-phase samples into the scattering from each phase. Complete 2-d scattering patterns for each phase can be reconstructed from the series of extracted spherical harmonics. The use of the spherical harmonics leads naturally to the evaluation of the levels of preferred orientation of each phase. The method is demonstrated using the scattering from molecular composite films based on isotactic polypropylene and a thermotropic liquid crystalline polyester. We show how the methodology may be applied to systems where the scattering from partially aligned samples of the pure components are available and to data where no other information is available. © Springer-Verlag 2005.