抄録
Poly-xylyleneadipamide filaments are produced by melt spining followed by either rapid cooling in quenched air or by gradual cooling in a heated hood.
The cross-sectional distribution of birefringence of undrawn monofilaments produced by there two methods is observed by polarized microscopy. The relationship between birefringence distribution and mechanical properties of the undrawn filament is discussed.
The results are following: 1) When molten filaments are gradually cooled by using a heated hood, their cross sectional distribution of birefringence is more uniform than that when they are rapidly cooled. Namely, the birefringence difference between the surface and the center of the monofilament is little.
2) Tenacity and elongation at break of a undrawn filament having a uniform birefringence distribution are larger than those having a wide distribution.
3) The birefringence distribution of undrawn filaments has an effect upon drawing behavior. Namely, the filament surface which has higher molecular orientation bears the load in drawing, and a filament which has a uniform distribution can be drawn up to a higher draw ratio.
