STUDIES ON THE KINETICS OF CRYSTALLIZATION OF POLYPROPYLENE FIBERS DURING MELT SPINNING

摘要

A new way of applying the on-line experimental data and some basic theory to study the mechanism of orientation and crystallization of melt spinning process has been described. The relationships among birefringence, stress and crystalline index for polypropylene fibers have also been developed to understand the phenomena happened in the spinning line. By the comparison of model prediction and on-line experimental birefringence, a suitable mechanical model to simulate the change of the profiles along the spinning line has been chosen and the structural development mechanism has also been discussed. The results show that the orientation for polypropylene fibers is determined by deformation and deformation rate along the spinning line, and the rapid crystallization is determined by the orientation of tied molecular.