writer：Zhongzhu Liu, Guoqiang Zheng(通讯作者), Kun Dai, Chuntai Liu and Changyu Shen
keywords：crystallization,extrusion; fibers,polypropylene,structure–property relations
source：期刊
specific source：Journal of Applied Polymer Science, 2016, DOI: 10.1002/app.43454
Issue time：2016年

Polymer processing methods generally play a crucial role in determining the development of microstructure in the fabricated product. In this study, isotactic polypropylene (iPP) melt containing 0.05 wt % b-nucleating agent (b-NA) was extruded via a melt flow rate indicator. The molten extrudate was stretched into a fiber upon various take-up velocities (TVs). The microstructures of the fiber were investigated by differential scanning calorimeter, two dimensional wide-angle X-ray diffraction, and small-angle Xray scattering. Also, its tensile properties (including tensile strength, modulus, elongation at break, and toughness) were measured by tensile test. Interestingly, the tensile strength (135.0 MPa) of a melt-spun b-nucleated iPP fiber fabricated at 400 cm/min was enhanced by 115.2%, compared with that (62.7 MPa) prepared at 100 cm/min, with a considerable increment in toughness (from 661 to 853 MJ/m3). The enhancement mechanism for tensile properties was discussed based on the microstructures. This work offers a simple approach to prepare b-nucleated iPP fibers with excellent strength and toughness.