Effect of draw ratio on fiber structure development of polyethylene terephthalate

Ultra-SAXS observation of fibril-sized structure formation after the necking of poly(ethylene terephthalate) and poly(phenylene sulfide) fibers

“…The position also hardly changed with the draw ratio, but the peak separation became difficult owing to the decrease of the streak intensity, in particular at low qeq. The position of the peak was inclined approximately 20° from the equator, which was similar to the inclination of the X-pattern observed for SAXS [13].…”

“…Image processing could not be performed because the image extracted from the necking movie in this experiment was rough and blurred. Therefore, the time resolution was estimated by the length and the fluctuations of the necking with reference to those previously reported [13,20]. That is, it was estimated that the neck fluctuation was 0.09-0.14 mm, the neck length was 0.13-0.28 mm for PET fibers, and the neck fluctuation was 0.095 mm, the necking length was 0.06 mm for PPS, where the size of the X-ray beam was 0.01 mm and the fiber running speed was 110 m/min.…”

“…The heat of crystallization was determined using the heat of fusion of the drawn fibers measured by DSC ( Table 1). The crystallization induction time and crystallization rate were assumed, as shown in Table 2, with reference to the results of a previous report [13] and the value obtained by Ide et al [20]. The estimated fiber temperature is shown in Table 2.…”

“…However, although the inter-fibrillar void should also collapse with the elapsed time for PET, it rather increased with time in particular for DR 5.6. This could be explained by the voids formed by the crystallization, which occurred less than 1.0 ms after necking [13].…”

“…This smectic structure was considered to be the precursor of a microfibrillar structure. From our previous research [13] coupled with that of Yamaguchi, the amounts of smectic phase and d-spacing during drawing of PET fibers were analyzed in more detail. As a result, the fiber strength was observed to be determined by the amount and orientation of the inter-microfibrillar tie-chains linking the smectic phase, not the microfibrillar structure itself.…”