The high speed melt spinning of nylon-66 and its mathematical modelling

On spinline diameter, temperature and birefringence profiles were measured for four different molecular weight and different polydispersity nylon-66 materials at the spinning speed from 1700 to 6300 meters per minute and mass throughput of 2.3-3.3 g/min. The molecular weight was in the range of 13,000-15,600.

A mathematical model developed by Zieminski [14] was used and comparisons between theoretical predicted profiles with experimental results were made to better understand the structure development during processing.

Spinline tension at the take-up device was measured and elongational viscosity and heat transfer coefficient ware calculated using an inversion program developed by Bheda [94].

It seems that there was not significant difference in diameter and temperature profiles among the four materials. The high molecular weight sample had a little faster birefringence increase than the others at the position where crystallization occurred.

The experimental diameter and temperature results showed good agreement with theoretically predicted profiles, especially after introducing experimentally obtained elongational viscosity and heat transfer coefficient. Birefringence showed good agreement between experimental and theoretical predicted profiles at the take-up velocity of 6000 meters per minute. It was not fitted well for the birefringence profiles at lower take-up velocities. This may be caused by the incorrect crystallization kinetics relation used in the present model.