High-Strength, Low-Permeable, and Light-Protective Nanocomposite Films Based on a Hybrid Nanopigment and Biodegradable PLA for Food Packaging Applications

ACS Omega. 2019 Sep 3;4(12):14947-14954. doi: 10.1021/acsomega.9b01731. eCollection 2019 Sep 17.

Abstract

Herein, a multifunctional filler, a dye (organic)-clay (inorganic) hybrid nanopigment (DCNP), was embedded into polylactic acid (PLA) to fabricate a colored biodegradable/biocompatible film, which is explored as a high thermomechanical resistant as well as a superior light and mass transport barrier for food packaging applications. In this respect, the DCNP was synthesized through a wet chemical process with a reaction yield of 76% and incorporated into a PLA matrix at various concentrations using a solution casting method. The morphological characterizations revealed partially intercalated/exfoliated structure for PLA-DCNP films. The samples filled with DCNP showed up to 20% and 12 °C improvements in storage modulus (E') and glass transition temperature (T g), respectively, compared to those with neat PLA. Incorporation of a small amount of DCNP into the PLA matrix significantly declined the water vapor and gas permeability of PLA by 36 and 54%, respectively. The optical property investigations indicated remarkable color characteristics and light protection performance of the samples containing DCNP. The results also showed better performance of the PLA-DCNP film compared to that of the PLA-Cloisite 20A sample at an identical filler loading. In conclusion, the desirable properties of the resulting films highlighted the potential application of such nanocomposite films as a promising option for food packaging materials.