Strength Enhancement of Recycled LOCC-Based Paper Using Chemical Additives: A Review

The growing environmental concerns surrounding plastic pollution and deforestation have accelerated the need for sustainable alternatives in the packaging industry. Local old corrugated containers (LOCC), a readily available source of recycled fibers, have emerged as a promising raw material for manufacturing carry bag paper. However, LOCC-based paper often exhibits inferior mechanical properties, primarily due to fiber degradation, reduced bonding potential, and contamination from repeated recycling cycles. This review comprehensively examines the use of chemical additives to enhance the strength properties of carry bag paper made from LOCC. The discussion spans traditional wet-end additives, such as cationic starch and polyacrylamide (PAM), which improve internal bonding and fiber retention, to advanced crosslinking agents like glyoxalated polyacrylamide (GPAM) that impart wet strength. Surface sizing techniques, employing starch and synthetic polymers, are highlighted for their contribution to surface integrity and burst resistance. The role of enzymatic and biochemical treatments, including cellulases and laccase-mediator systems, is also addressed, showcasing their potential in modifying fiber surfaces for enhanced bonding. Emerging nanotechnologies, particularly the use of microfibrillated and nanocellulose, offer significant strength improvements up to 97% due to their high surface area and hydrogen bonding capabilities. The review also considers the economic and environmental viability of these additives, emphasizing the need for biodegradable and cost-effective solutions. By integrating multiple chemical strategies, manufacturers can significantly upgrade the performance of LOCC-derived paper, making it a viable alternative for high-strength carry bag applications. This comprehensive synthesis aims to guide researchers and industry professionals in selecting and optimizing additive systems for sustainable paper production. A combination of instrumental techniques, such as UTM, burst and tear testers; SEM-EDX, XRD, X-ray XPS, FTIR, contact angle measurement, and zeta potential, can be used to evaluate mechanical strength, surface morphology, chemical interactions, and fiber characteristics of LOCC-based carry bag paper treated with chemical additives for enhanced performance.