Combining Nanocellulose and Natural Rubber in Paper Packaging with Superior Barrier Properties and Antibacterial Activity

Creating more sustainable and eco-friendly packaging with superior mechanical and barrier properties presents a significant scientific challenge. Paper-based packaging offers a potential solution to environmental concerns in this field, given its renewable, biodegradable, and recyclable nature. However, enhancing its barrier properties is crucial for broader applications. This study combined the excellent oxygen and oil barrier characteristics of cationic cellulose nanofibrils (CCNF) with the water vapor barrier properties of natural rubber latex (NRL) to produce a multilayer coated paper with enhanced barrier properties. The barrier against water, water vapor (WVTR at 23°C and 50% RH), oxygen, and grease was assessed based on the number of deposited layers. A five-layer alternating coating with CCNF and NRL (CCNF/NRL/CCNF/NRL/CCNF) decreased the paper's water vapor transmission rate by approximately 20 times (from 732 to 36 g m-2day-1) and reduced the oxygen transmission rate by about 4000 times (from 155,000.00 to 38 cm3m-2day-1). The resistance to oil and grease achieved the highest barrier level with a kit rating of 12. Additionally, the outer cationic CNF layer provides antibacterial properties against E. coli, with over 90% mortality, adding a valuable functionality for packaging applications. This bio-based, fluorine-free, recyclable, and antibacterial multilayer-coated paper demonstrates exceptional barrier properties, making it a promising candidate for increasing sustainability in the packaging industry.