Effect of Colorants and Process Parameters on the Properties of Dope-Dyed Polylactic Acid Multifilament Yarns

Abstract

The color of textile fibers is typically imparted by submersion in a high-temperature dye bath. However, the treatment of the effluent is challenging and the textile industry is therefore a major source of water pollution. Current fashion trends favor biobased polymers such as polylactic acid (PLA) but exhaust dyeing at high temperatures causes hydrolytic degradation, reducing the crystallinity and tenacity of the yarn. To preserve the mechanical properties of PLA-based textiles, an alternative to exhaust dyeing called dope dyeing can be used, wherein colorants are incorporated into the polymer matrix during melt spinning. We evaluated this process by dope dyeing PLA with several colorants, then testing the thermal, physical, and mechanical properties of the yarn and the physical properties of circular-knitted fabrics. Although the colorants affected the crystallization behavior at lower cooling rates, during the melt-spinning process, the drawing speed had a greater effect on the crystallinity and mechanical properties of the dyed yarn. Scanning electron microscopy revealed that the colorants were well dispersed in the PLA matrix. We found that the colorants did not affect the physical properties of the knitted fabric. Our results can be used to develop more environmentally beneficial dope-dyed PLA yarn with improved mechanical properties.

Historically Inspired Strategy to Achieve Sustainable and Effective Coloration of Bioplastics

“…The addition of LWP in PLA-based biocomposites causes a decrease in tensile strength, negligible (−1.9%) for PLA_0.1 LWP and slight (−7.0%) for PLA_1 LWP; analogously, the elastic modulus undergoes a moderate decrease. The nanofiller does not produce reinforcing effects on the poly (lactic acid) matrix but also does not create excessive weakening by intervening as defects in the molecular structure of the polymer. − Basically, the LWP has a good coloring effect without dramatically affecting the tensile properties of the polymeric matrix. The plasticizing effects that LWP seems to induce under certain conditions deserve further investigations of the specific chemical and physical interactions between the matrices and the pigments.…”

Experimental and Numerical Study of Printing Strategy Impact on the Mechanical Properties of Sustainable PLA Materials

“…This can be attributed to the additives which changed the color of the filament to the white one. These additives can increase the micro porosity of the material and reduce the adhesion of layers, thus reducing the tensile strength [ 39 ]. The composite material Wood PLA exhibited the lowest tensile strength and lowest elongation.…”

Hydrophilic Modification of Polylactic Acid Fiber and the Usage of Natural Dye for Multi-Levered Improvement of the Fabric Staining Depth and the Stability Effect

“…8,9 The staining of PLA could be carried out on fibers, yarns, or fabrics, but direct staining at the fiber stage was not a widely practiced method. 10 Presently, the primary method employed for coloring PLA materials is the utilization of disperse dyes. However, according to the research conducted by David Karst and Yiqi Yang, it was observed that the adsorption rate of all disperse dyes with a solubility value over 25.0 (J/cm 3 ) 0.5 was found to be below 70% for PLA.…”

“…The staining of PLA could be carried out on fibers, yarns, or fabrics, but direct staining at the fiber stage was not a widely practiced method . Presently, the primary method employed for coloring PLA materials is the utilization of disperse dyes.…”