E. Andreassen et Oj. Myhre, INFRARED-SPECTROSCOPY MEASUREMENTS OF RESIDUAL-STRESSES IN POLYPROPYLENE FIBERS, Journal of applied polymer science, 50(10), 1993, pp. 1715-1721
Average residual stresses in polypropylene fibers, produced in a full-
scale short-spin line, are estimated from the shift of the IR absorpti
on peak at 975 cm-1. Linearly polarized incident IR radiation is used
to separate between stress components parallel and perpendicular to th
e fiber axis. For all the fibers in this study, the axial stress compo
nent is larger than the average stress perpendicular to the fiber axis
. Axial and perpendicular stresses are correlated with draw ratio and
polydispersity index. For narrow molecular weight distributions (M(w)/
M(n) < 4-5), the axial stress increases with increasing draw ratio. Av
erage stress perpendicular to the fiber axis decreases with increasing
draw ratio for all the molecular weight distributions in this study (
M(w)/M(n) = 3-6). Measurements of residual stresses are consistent wit
h other results characterizing molecular structure and mobility. An ex
pression for estimating the stored deformation energy is discussed. (C
) 1993 John Wiley & Sons, Inc.