Antimicrobial low-density polyethylene/low-density polyethylene-grafted acrylic acid biocomposites based on rice bran with tea tree oil for food packaging applications

Abstract

Natural volatile antibacterial and anti-mycotoxin tea tree oil (TTO) with rice bran (RB) were used as a solid carrier for achieving a sustained release profile with high antimicrobial efficiency in polyethylene films. Acrylic acid (AAc) monomer was grafted onto a low-density polyethylene (LDPE) through melt blending using a Brabender Plasti-Corder. The low-density polyethylene-grafted acrylic acid (LDPE- g-AAc) was thoroughly characterized by attenuated total reflectance–Fourier transform infrared spectroscopy. LDPE and LDPE- g-AAc (80/20) were mixed with different contents of untreated RB and treated TTO/RB using melt blending to obtain sustainable composites, namely LDPE/LDPE- g-AAc/RB and LDPE/LDPE- g-AAc/TTO-RB, respectively. The effect of the addition of untreated and treated RB on the properties of biocomposites was assessed by using mechanical, barrier, and thermal properties. A prominent decrease in water vapor transmission rate occurred when adding 30 wt% of TTO/RB to LDPE/LDPE- g-AAc blend compared to virgin polymer. This decrease was due to the barrier effect of lignocellulosic material, particularly at high bio-filler content. The prepared biocomposites revealed good thermal stability when compared to virgin LDPE. Moreover, the biodegradability and antimicrobial properties of LDPE/LDPE- g-AAc/TTO-RB biofilms were enhanced with increasing TTO/RB contents from 10 phr to 30 phr due to the combination between LDPE- g-AAc and TTO. The obtained data revealed excellent possibility for using biopolymer grafted with antimicrobial TTO by adding RB for food packaging and biomedical purposes.