Layered double hydroxides based composite materials and their applications in food packaging

Abstract

Layered double hydroxides (LDHs) are 2D laminar clay materials [Hydrotalcite (HTs)- like] comprising of brucite-like layers (positively charged) with charged compensating anions and water molecules in interlayered region. Because of their compositional variation, HTs/LDHs as multifunctional materials have attained significant attention in different fields such as adsorbent in environmental remediation, catalysts in photo/sonocatalyst and biomass conversion into biochemicals and biofuels, delivery agents of drug/cosmeceutical/ agrochemicals, active materials in voltaic and photovoltaic cells, additives in concrete and packaging materials etc. The properties of HTs/LDHs including exchange ability of different anions, the resiliency of different metal cations in host layers, large surface area, and tunability of the synthetic parameters with a crystal structure. Owing to their unique properties, HTs/LDHs as filler/additive materials have gained a lot of attention to produce natural/synthetic polymer composites with improved barrier, thermal, and mechanical properties. This class of clay has the ability to intercalate different types of natural/synthetic compounds (organic and inorganic) in interlayer space with better loading, controlled and slow release of intercalated molecules, biocompatibility, easier surface modification and varied lattice composition etc. These have been recently also explored as additives in polymeric matrix because of their ability to increase the hydrophobicity of polymer surfaces with a reduction of water permeability and better barrier of polymers. Consequently, research related to HTs/LDHs based polymer hybrid/composite materials has been growing because of their applicability and environmentally friendly nature with low cost of production for improved/active/bio-based packaging material systems. The present study focuses on using HTs/LDHs-based hybrid or composite materials for food packaging applications with improved mechanical, thermal, and barrier properties of packaging materials and aggrandized shelf life and organoleptic/ sensoric/ nutritional values of food products.