Some problems in melt spinning processes. II. Molecular orientation in the course of melt spinning

Abstract

The approximate solutions of the three-dimensional, fundamental equation for the molecular orientation of a spun fiber are obtained, a rigid ellipsoid model for the molecular segments or the paracrystalline structure being assumed. A rate of strain G (sec.−1) of a molten fiber and a rotational diffusion constant D (sec.−1) of the segment are approximated as a function of time t (sec.) as follows: Under the conditions, 1>>G0t>>G1G2>>G2t3>> … and 1>>D0t>>D1t2>>… a coefficient of the molecular orientation f of spun fiber is found to be: The applicability of these approximate, theoretical results is extremely limited in the neighborhood of the spinneret under practical melt spinning conditions. However, the theory should be useful in the case where the polymer temperature is near its melting temperature and the extension rate of spinning fiber is small.