Characterization of an antioxidant polylactic acid (PLA) film prepared with α-tocopherol, BHT and polyethylene glycol using film cast extruder

Abstract

Polylactic acid (PLA) films were prepared with α-tocopherol, buthylated hydroxytoluene (BHT), and polyethylene glycol 400 (PEG 400) using a cast film extruder in an effort to create an antioxidant film. Film properties were characterized by radical scavenging activity and thermal, physical, and gas barrier properties. Final resin compounding and pelletization was achieved by a twin screw extruder and a pelletizator to permit the homogenization of all resin components prior to film casting. Three different PLA films were fabricated for this study: pure PLA film, PLA film with BHT and PEG 400 (BP-PLA film), PLA film with α-tocopherol, BHT, and PEG 400 (ABP-PLA film). The addition of PEG 400 into the pure PLA film decreased the glass transition temperature ( T g) of the film. The BP-PLA and ABP-PLA film had around 51 °C of T g while pure PLA film had 66 °C. Due to the decreased T g of both the BP-PLA and ABP-PLA film, both films had an increased elongation at break (%E). The addition of plasticizer into the pure PLA film also caused increased water vapor permeability (WVP) and decreased oxygen permeability (OP). The ABP-PLA film had highest DPPH radical scavenging activity, 90%, while pure PLA and BP-PLA film had only 0 and 14%, respectively.