Abstract
PTT polymer was spun by high-speed melt spinning method, and the effects of take-up velocity and mass flow rate on the fiber structure and properties were investigated. The changes in the structure and property with take-up velocities were studied by measuring WAXD, DSC, density, birefringence, dynamic viscoelasticity and tensile test, etc. The orientation in crystalline phase obtained by WASD increased with the increase of take-up velocity. The orientation-induced crystallization of PTT fibers in high-speed melt spinning appeared at the take-up velocity of about 3~4km/min. This tendency was confirmed by the results of DSC thermograms, density, and birefringence. The birefringence increased abruptly up to take-up velocity of 4km/min, but it became almost constant when the take-up velocity exceeded 4km/min. The tendency was confirmed by the result of dynamic viscoelasticity. The maximum point of $\alpha$$_{c}$-dispersion shifted to a higher temperature, but shifted to a lower temperature when the take-up velocity exceeded 4 km/min. The fine structure and the mechanical properties were not affected significantly by mass flow rate.e.