The variation of fibrils’ number in the sea-island fiber -low density polyethylene/polyamide 6-

In melt spinning of low density polyethylene/polyamide6 (LDPE/PA6), fibrils’ number in LDPE/PA6 blend fiber is calculated at different take-up velocity. Firstly, PA6 fibrils are dispersed in the LDPE matrix in LDPE/PA6 blend fiber (55:45, weight ratio). The number of PA6 fibrils increases with an increase of the take-up velocity. Because the shorter processing time suppresses the coalescence at the high take-up velocity, it causes an increase of PA6 fibrils. Besides, the irregular shape of PA6 fibrils’ cross section also confirms fibrils’ coalescence. Secondly, LDPE fibrils are dispersed in the PA6 matrix in LDPE/PA6 blend fiber (6:94, weight ratio). However, the number of LDPE fibrils doesn’t change no matter how the takeup velocity is. In case of LDPE/PA6 (6:94) blend fiber, the low weight ratio of the dispersed LDPE causes the absence of fibrils’ coalescence, so fibrils’ number does not change. In conclusion, the variation of fibrils’ number implies the existence of the coalescence phenomenon in the fiber spinning process. The variation of fibrils’ number in the sea-island fiber is of practical importance for manufacturing the micro-fine fiber, and is a method to investigate the coalescence behavior in the extensional flow.