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 degrees 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 degrees 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.