X-Ray Diffraction of the Supramolecular Structure of Polypropylene Yarns

Abstract

We show that for orientational drawing of polypropylene multifilament yarns within the draw ratio range 4.2-5.6 at elevated temperature, we observe practically complete transition of the folded-chain lamellar crystallites to fibrillar crystallite formations of stretched chains, resulting in a significant increase in the relative breaking load for the yarns. We established that increasing the preliminary spinneret draw ratio, which considerably reduces the possibility of formation of a*-oriented foldedchain lamellae, lets us obtain stronger yarns.