OS0601 Effect of Orientation on Mechanical Properties and Destruction Behavior of Poly(lactic acid) Screws
Details
Effects of extrusion ratio (ER) and lubricant during extruding on mechanical properties and fracture behavior of poly(lactic acid) (PLA) screws were investigated in terms of shear strength and acoustic emission (AE). Self-reinforced PLA screws were manufactured from axially extruded PLA billets by forging. Shear strength for PLA screw increased by drawing. The result suggested that drawing is effective method to improve shear strength for PLA screws. This might be due to orientation of molecular chains during drawing. Shear strength did not increase linearly with ER, and shear strengths for screw extruded at low ER were slightly higher than that for screw extruded at high ER. This might be due to molecular orientations for screw extruded at high ER were lower than that for screw extruded at low ER. From AE measurement, AE event occurred in the specimens with extrusion was lower compared to that without extrusion, whereas AE energy was higher. This suggested that the number of micro-damages which occurred in extruded specimen was fewer and the size of micro-damages was larger.
