X-Ray Analysis of Polypropylene Thread Crystallization during Spinning

The need to account for the anisotropy of compact samples pressed from ground polypropylene (PP) fibers was demonstrated during a determination of the degree of polymer crystallinity using x-ray structure analysis. The destruction of the spherical scattering symmetry of x-rays by PP fiber samples was proven to be unrelated to the polymer amorphous phase. A method for calculating the degree of crystallinity of fiber composites from the normalized intensity of the diffuse halo of the studied composites and standard powdered PP samples was proposed. It was found that the degree of spinneret drawing of PP composite threads had practically no effect on the degree of polymer crystallinity whereas the simultaneous effects of temperature and orientation factors during solid-state drawing increased the fiber crystallinity by 1.15-1.17 times with degree of drawing 4.2-5.6, which was one of the reasons for the increased thread strength.