Effect of Drawing Conditions on Crystal Structure and Mechanical Properties of Melt-Spun Polylactic Acid Fibers

Polylactic acid (PLA) is a biomass-based, eco-friendly, and biodegradable aliphatic polyester. Compared to aromatic polyesters, PLA is not suitable for applications that require high strength and heat resistance. In this study, the extrusion parameters of the melt-spinning process of PLA, namely, the godet temperature (95 and 100 °C), draw ratio (2.0–4.0), and take-up speed (4000–4400 m/min) were optimized. As the draw ratio and take-up speed of the fiber increased, the tensile strength and melting temperature increased owing to orientation-induced crystallization until necking of the fibers occurred. The properties of the PLA fibers were measured using X-ray diffraction, a universal testing machine, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The maximum crystallinity achieved in the PLA fiber was 84.76%. The tensile strength of the fiber was increased from 86.25 to 124.06 MPa and the melting temperature was increased from 149.51 to 155.14 °C. Therefore, it is concluded that understanding the correlation between the process parameters and fibers and combining them appropriately facilitates the control of the mechanical and thermal properties of the PLA fiber.