Influence of Surface Treatment of CaSO4 on the Drawability and Physical Properties of the PBAT/PLA/CaSO4 Composite Sheet

This study investigated the effect of surface treatment of CaSO 4 on the physical properties of the composite film manufactured using an inorganic additive CaSO 4 and the biodegradable polymers, poly(butylene adipate- co -terephthalate) (PBAT) and poly(lactic acid) (PLA). Using a twin-screw extruder, the CaSO 4 content of the PBAT/CaSO 4 composite was prepared to be 1, 5, and 10 wt%, and the surface treatment of CaSO 4 with stearic acid was studied for changes in mechanical properties and dispersibility of the composite. The surface-treated CaSO 4 showed improved dispersion in the matrix polymer and improved strength and elongation compared to before surface treatment at all contents of the PBAT/CaSO 4 composite. In addition, using a small amount of PLA, PBAT/PLA/CaSO 4 composite sheets were prepared and biaxially stretched. The draw ratio of the PBAT/PLA/CaSO 4 composite sheet was increased by CaSO 4 surface treatment with stearic acid, and the mechanical properties of the stretched film were improved.