The Application of X-Ray Diffraction Method to the Measurement of Crystal Deformation and Crystal Modulus of High Polymers

Abstract
Elastic modulus EI of crystalline regions of various high polymers in the direction parallel to the chain axis were measured using an X-ray diffraction method. The crystal deformation can be detected directly by the diffraction peak shift as a function of applied constant stress. The stress in the crystalline regions is assumed to be equal to that applied to the specimen. The validity of this assumption has been proven experimentally for polyethylene, poly(p-phenylene terephthalamide) and so on. The EI values were discussed in relation to molecular conformation and deformation mechanism of the chains.