The determination of longitudinal crystal moduli in polymers by spectroscopic methods

Experimental methods for determining longitudinal crystal moduli of polymers were evaluated in light of recent proceesing methods that produced macroscopic Young's moduli which exceeded ultimate values as found by the x‐ray diffraction method. The spectroscopic techniques of Raman and coherent inelastic neutron scattering yielded higher longitudinal crystal moduli than x‐ray diffraction, and from calculations described herein it is concluded that these spectroscopic values are better estimates of the maximum Young's moduli in fully aligned and crystalline polymeric materials.