Studies on mechanical, optical and barrier properties of biodegradable PLA-PBAT blend film with EGMA compatibilizer and micro ZnO

Abstract

PLA-PBAT was melt blended using Twin screw compounding extruder in three ratios (60:40, 50:50, 40:60%) with EGMA as compatibilizer (2.5 wt%). Tubular blown films were made using a tubular blown film extruder. In one formulation (50:50%) micro ZnO 1% was also included. The PLA-PBAT blends were tested for their mechanical, thermal, optical and physical properties. Due to ductility/flexibility of PBAT, tensile strength in machine direction (M/D) decreases with increasing PBAT concentration. However, in the transverse direction (T/D) the tensile strength increases with increase in PBAT concentration. Tear strength results show maximum strength in proportion of 50:50 in both machine and transverse direction. The PLA-PBAT 50:50 % blend filled with ZnO 1% has higher tear strength in both machine and transverse direction. Improvement in the dart impact strength was observed. Luminious transmittance was increased, MFI increased with increase in PBAT composition. Water vapour transmission rate was not decreased by increasing PBAT content since PBAT has slightly higher gas permeability than that of PLA. A complete biodegradation (100%) of PLA/PBAT blend was achieved in all PLA-PBAT blends and with micro ZnO, because of high biodegradability nature of PLA and PBAT polyesters. The test was done up to 210 days in soil burial method.