Two-directions mechanical strength and high-barrier mechanisms of cellulose nanocrystal- based hybrids reinforced packaging with nacre-mimetic structure

This work represents a new composite film with a nacre-mimetic structure through the alignment of hybrids comprising cellulose nanocrystals and ball-milled boron nitride (CNC-BNNS), within polypropylene carbonate (PPC) endowed with various properties. The impact of CNC-BNNS hybrids on mechanical strength mechanisms was evaluated under two-directional forces, marking the first such assessment. Using a solution casting approach, incorporating 5 % CNC-BNNS improved tensile strength by 67.6 % longitudinally and 4 % in the cross-sectional direction of the prepared PPC composite. Adding 5 %, CNC-BNNS increased the maximum degradation temperature by 12.1 °C and the glass transition temperature by 6.8 °C, as anticipated. Through synergies between CNC-BNNS and PPC, composite film with 15 % CNC-BNNS displayed enhanced barrier properties, notably reducing oxygen permeability (OP) and water vapor permeability (WVP) by 26.1 % and 90.9 %. Consequently, strawberries and blueberries packaged with these films saw extended shelf lives of up to 6 days. Furthermore, the degradation mechanisms of the composite in natural soil were investigated to assure the environmental issue, revealing a fast degradation rate of 44.5 % over 90 days. This study proposes a sustainable method for producing high-performance composite materials with antioxidant, liquid leakage resistance, and UV resistance, making them ideal for food packaging.