Efficient Gas Barrier and Antibacterial Properties of Poly(lactic acid) Nanocomposites: Functionalization with Phytic Acid-Cu(II) Loaded Layered Clay.

Yongzhen Lei,Jin Yao,Long Mao,Zhihan Li

doi:10.3390/ma13092033

Abstract

Poly(lactic acid) (PLA) represents one of the most promising and attractive bio-based polymers for green packaging. However, toughness, gas barrier and antibacterial properties of pure PLA films cannot compete with those of traditional petroleum-based active packaging plastics. To fill this gap, utilization of excellent chelating properties of phytic acid (PA), functionalized layered double hydroxides (LDHs@PA-Cu(II)) was firstly synthetized via facile deposition and chelation of one-step assembled PA-Cu(II) coordination compounds on the surface of layered clay. Furthermore, LDHs@PA-Cu(II)/PLA nanocomposites were prepared by blending LDHs@PA-Cu(II) and pure PLA via solution casting evaporation process. After adding only 1 wt % LDHs@PA-Cu(II), elongation at break and tensile strength increase by 53.0% and 18.9%, respectively, and the oxygen relative permeability decreases by 28.0%. Due to the strong interface interaction and heterogenous nucleation, the reinforcement effect of LDHs@PA-Cu(II) at low loadings is remarkable. Meanwhile, owing to the antibacterial activity of PA-Cu(II) coatings, the antibacterial rate (against Escherichia coli) of LDHs@PA-Cu(II) exceeds 99.99%. Furthermore, the corresponding LDHs@PA-Cu(II)/PLA nanocomposites also show outstanding antibacterial properties, which will be a promising candidate for active packaging application.

Highlights

In recent years, food safety concerns have given rise to the development and relevant applications of active packaging materials [1,2]
After adding only 1 wt % layered double hydroxides (LDHs)@phytic acid (PA)-Cu(II), elongation at break and tensile strength increase by 53.0% and 18.9%, respectively, and the oxygen relative permeability decreases by 28.0%
As a promising form of active packaging, antibacterial packaging is beneficial to food preservation, the reason is that active packaging can delay food spoilage through the deactivation or inhibiting the growth of various microorganisms [3]

Summary

Introduction

Food safety concerns have given rise to the development and relevant applications of active packaging materials [1,2]. Active packaging can prolong the shelf life of food by improving the gas barrier, antibacterial and antioxidant properties of packaging materials [3,4]. While trying to reduce the gas barrier properties of packaging materials, using appropriate antibacterial packaging technology is an effective way to prolong the shelf life of food. It is strongly necessary to develop fully biodegradable polymeric packaging materials with excellent comprehensive performance to alleviate the dependence on petroleum-based polymer. Among all these biodegradable polymers, poly(lactic acid) (PLA) has attracted considerable attention in the recent decades due to its effective

Objectives

Methods

Conclusion