Application of grazing incidence x-ray diffraction to polymer blends

The physical properties of polymer blends consisting of one or more crystallizable components are affected by the microstructure of these materials. In particular, the degree of crystallinity can be influenced by processing parameters, and the crystallinity, as well as the phase distribution, may vary as a function of depth through an injection molded part Conventional x-ray diffraction techniques can provide information regarding both phase composition and degree of crystallinity, but, because of the relative transparency of these materials to wavelengths generally available in the laboratory, these techniques provide information representative of only the bulk. By employing parallel beam optics at varying grazing incidence angles, the x-ray sampling depth can be varied without loss of resolution. This technique can be used to vary the effective analysis depth from the top several hundred angstroms for low razing incidence to centimeters for transmission diffraction patterns. Grazing incidence techniques have found initial application in the characterization of thin metallic and ceramic films. This paper demonstrates the feasibility of using parallel beam to depth profile low atomic number materials. The specific application of this optics technique to the characterization of injection molded polymers, including a blend of bisphenol-A polycarbonate (PC) and polybutylene terephthalate (PBT), willmore » be presented.« less