Evaluation of the crimp formability of side-by-side PLA/PTT bicomponent fibers

Abstract

To explore the feasibility of developing bio-based elastic fibers, bio-based polylactide (PLA) and polytrimethylene terephthalate (PTT) were selected for fabrication of side-by-side bicomponent fibers using bi-constituent melt-spinning technology. The structure development and performance of PLA/PTT bicomponent fibers was investigated using thermal mechanical analysis, differential scanning calorimetry, and wide-angle X-ray diffraction in order to evaluate the crimp formability of PLA/PTT bicomponent fibers. The PLA and PTT components could form regular boundary structure and exhibit excellent interface compatibility by regulation of the rheological behavior of the two melts. In the fiber forming process, the PTT component in PLA/PTT bicomponent fibers experienced higher tensile stress, and thereby enhanced the crystal and oriented structure development, while the structural evolution of the PLA component was inhibited. The difference in the structure of the two components causes the imbalance force existence in the PLA/PTT fibers, which is the main reason of fiber crimp. In addition, the crimp formability of the PLA/PTT fibers could be enhanced by expanding the shrinkage stress difference between the two components, which could be realized by increasing the PTT ratio in PLA/PTT bicomponent fiber or draw ratio. The maximum crimp extension that could be achieved was 85% for the bicomponent fibers with PLA30/PTT70 ratio at a draw ratio of 4.2.

Disclosing the fatigue deformation mechanisms of different types of poly (ethylene terephthalate) industrial fibers on the base of the multiscale structural evolutions

“…where Δn is measured birefringence, x is percent crystallinity, f c is crystal orientation which was determined from an azimuthal scan of the (010) and (100) reflection, Δn 0 c is intrinsic crystal birefringence (0.220), and Δn 0 a is intrinsic amorphous birefringence (0.275). 29…”

“…The study calculated detailed crystalline structure parameters, such as the crystalline orientation factor and the fraction of crystal and amorphous according to methods outlined in previous reports. 1,[29][30][31]…”

Evolution of interfacial formation and configuration control of bicomponent fiber during full spinning process

“…The fibers produced by bicomponent spinning are typically used to make functional fibers for the textile industry according to their cross-section type: islands in sea ultrafine fibers or segmented pie ultrafine fibers with two components that are easy to split, 1,2 sheath/ core bicomponent fibers with a specific functional sheath layer or core layer, 3 and side-by-side bicomponent fibers with a self-crimping function due to the different thermal shrinkage of two components. 4 Among them, the special performance of the extensibility and reversibility of side-by-side fiber depends on the crimp curvature which is believed to correlate strongly with the morphological configuration of the cross-section. 5 Therefore, the control of the interface is particularly critical to ensure the performance of the functional fiber.…”