Effect of Annealing Conditions on Molecular Structure and Physical Properties of Polypropylene Slit-Film Yarns

Abstract

The effects of various annealing temperatures and durations on the structure and physical properties of polypropylene (PP) slit-film yarns were investigated. Annealing led to a more developed crystal structure, even when the yarns were drawn before heat treatment. Annealing at 140 o C led to better developed crystal structures than that at 100 o C. Annealing primarily affected the crystalline structure, whereas little change was observed in the molecular orientation of the yarns. The slitfilm yarns annealed at 140 o C showed less than 1% shrinkage. A very low-shrinkage slit-film yarn was obtained on annealing for 10 min at 140 o C or 20 min at 100 o C.