Tensile Properties of Polypropylene Filaments

In this work, the tensile properties of polypropylene filaments, made by a melt-spinning and drawing process optimized in order to increase the elastic modulus of the filaments, are presented. The influence of molecular weight and the molecular weight distribution of the polymer on the tensile properties of the filaments, spun from polymers of different molecular weights with various composition ranges, was investigated. It was found that polypropylene filaments spun from a fiber-grade CR-polymer have better mechanical properties, when compared with filaments spun from a plastic-grade polymer with a broader molecular weight distribution. The characteristics of the filaments produced from binary blends are mainly dependent on the prevailing polymer in the blend; however, the addition of the other polymer exerts some influence as well. In both cases, a small percentage of added polymer improves the tensile properties of the filaments.