Study on the Characterization and Evaluation Methods of PA6 Chips for High-Speed Spinning

Abstract The reasons for the significant difference of PA6 spinnability are discussed. For this research project, BASF PA6 chips (BASF, Germany) and PA6 chips (GC, China) were chosen as research objects. We chose these two different chips because BASF PA6 chips are stable and GC PA6 chips are unstable in high-speed spinning. The measurement of relative viscosity, crystallization rate, content of extractable matter, molecular weight and its distribution, and Fourier transform infrared (FTIR) spectroscopy of extractable matter were systematically investigated. Moreover, the screw extrusion process of PA6 melt in high-speed melt spinning was simulated by a capillary rheometer, in which PA6 samples with different melting times were prepared to conduct the above-mentioned tests. Compared to BASF chips, the GC chips have the higher content of extractable matter, the greater and more variable relative viscosity, the greater molecular weight, and the wider distribution, causing the poorer spinnability in high-speed spinning. Furthermore, the extractable matter in GC chips is the same as that in BASF chips, which is confirmed by FTIR spectra.