Upcycling Leather and Paper Wastes to Biodegradable Materials for Packaging Displaying Excellent Multifunctional Barrier Properties

Abstract

A robust biodegradable packaging material was developed having superior barrier resistance to water, air, oil, grease, and microorganisms, which consisted of paper handsheets made from recycled old-corrugated container (OCC) wastes and collagen hydrolysate by upcycling leather wastes to reduce dependence on conventional packaging materials. The dechroming process of leather waste using 10% NaOH exhibited remarkable efficiency, achieving a 99.98% reduction in chromium content (< 44 ppb) within the World Health Organization’s recommended range. A coating recipe was formulated using collagen hydrolysate, chitosan, and glycerin (20%C-Ch-Gly) and applied on the OCC handsheets, demonstrating excellent barrier properties against hot oil, grease, and organic solvents (Kit rate 12). The developed packaging materials’ water vapor and air permeability decreased significantly by 150- and 10-fold, while tensile and burst strength increased by 140.84% and 77.73% compared to uncoated handsheets. The contact angle for water and organic solvents increased by 49.14% and 47.2%, ensuring excellent solvent repellency while maintaining a smooth and even morphological structure due to reduced average roughness by 76.67%. The optimized packaging material exhibited no cytotoxicity, displayed excellent antimicrobial properties, and was completely biodegraded in 11 weeks. This study demonstrated the potential of bio-based packaging as a viable alternative to hazardous, non-biodegradable plastics commonly used globally through upcycling leather and paper waste.

Graphical Abstract