High strength fiber obtained from a high stereoregularity metallocene catalyst-synthesized polypropylene

Abstract Recently, a high stereoregularity isotactic polypropylene (iPP) has been synthesized with the use of metallocene catalysts. In this study, effects of the molecular weight distribution and stereoregularity of iPP on the structure and properties of its fibers were analyzed. A fiber having a high tensile strength of 1.36 N/tex (1.2 GPa) and initial modulus of 27.4 N/tex (25 GPa) was obtained from metallocene catalyst-synthesized iPP of high stereoregularity. These features were better than those of both low stereoregularity metallocene catalyst-synthesized iPP fiber and equivalent stereoregularity Ziegler–Natta catalyst-synthesized iPP fibers. The metallocene catalyst-synthesized iPP fibers also had a lower creep strain at 125 °C. A lower degree of macroscale void development or suppressed fibrillation likely contributed to the higher attainable tensile strength of the metallocene catalyst iPP fibers. However, there were almost no differences in the melting temperature, dynamic viscoelastic behavior, crystallite size, and crystallinity observed between the spun and drawn fibers produced by the iPP synthesized by different catalysts.