Orientation of microcrystals for X-ray diffraction studies

A method is described for obtaining X-ray diffraction photographs, equivalent to those obtained under single-crystal rotation conditions, from materials available only in the form of fine microcrystalline powders of acicular or platy habit. The technique involves dispersing the crystalline powder in an appropriate thermoplastic polymer followed by streaming orientation of the particles in an extrusion process. The particles are held in their new positions by solidification of the polymer melt. With acicular powders, and using a polyethylene matrix, the orientation is improved by cold drawing. The oriented composite is immediately ready for X-ray studies.