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.