2021 Volume 77 Issue 2 Pages 66-75
High stereoregularity isotactic polypropylene (iPP) can now be synthesized even using metallocene catalysts. Fibers with higher tensile strength than those of Ziegler-Natta catalyst-synthesized iPP have been reported for iPP with 20 g/10 min melt index. The aim of this study is to further increase the tensile strength using 4 g/10 min melt index iPP. Metallocene iPP fibers with higher tensile strength, higher initial modulus,and lower creep strain at 125 ̊C than Ziegler-Natta iPP fibers were also obtained using 4 g/10 min melt index iPP. Moreover, the obtained maximum tensile strength of 1.39 N/tex (1.3 GPa) was higher than that of 20 g/10 min melt index iPP. The metallocene iPP fibers also had smaller crack diameters estimated by ultra-small angle X-ray scattering.
