Abstract
In order to study the relationship between fiber structure and physical properties during the drawing process, undrawn and drawn polypropylene multifilaments were manufactured on a spin-draw melt spinning machine and tested with a universal tester equipped with a temperature cabinet. The birefringence, density, and crystallinity of undrawn polypropylene multifilaments increased in the lower spinning temperature range with higher take-up velocity. In the case of drawn polypropylene multifilaments, the values of birefringence, density, crystallinity, tenacity, and elongation increased in the range of low take-up velocity until it was drawn to maximum ratio. For example, when drawn at a rate of 200 m/min, the maximum values of tenacity, elongation, and Young's modulus of the multifilaments were 8.5 g/d, 18.4%, and 48.8 g/d, respectively.