Integrated system coupling TEMPO-oxidized cellulose nanofibrils and cellulosic polyglycidyl methacrylate grafted fibers for enhanced retention and drainage in papermaking

The high-performance retention and drainage systems for papermaking is critical for achieving sustainability in papermaking. This study was aimed at examining the potential of 2,2,6,6-tetramethylpiperidine-1-oxyl oxidized cellulose nanofibrils (TOCNs), characterized by high carboxyl content, strong negative charge, and large specific surface area, as a replacement for colloidal silica (SiO 2 ) in the classic cationic polyacrylamide (CPAM)/SiO 2 /anionic polyacrylamide (APAM) system (CPAM/SiO 2 /APAM) in papermaking. The replacement objective was to improve the retention and drainage performance during papermaking and enhance paper sheet strength. The retention and drainage behavior of the CPAM/TOCNs/APAM system in papermaking and its impact on sheet strength were investigated. The results show that compared with the CPAM/SiO 2 /APAM system, the CPAM/TOCNs/APAM system exhibits superior retention and drainage ability, along with greater sheet strength enhancement. Although the incorporation of hydrophobic cellulose polyglycidyl methacrylate grafted fibers (CPGMAs) slightly reduce sheet strength, it significantly improves the drainage. Moreover, a synergistic effect between CPAM/TOCNs/APAM and CPGMAs on retention and drainage performance is identified. An innovative CPAM/TOCNs/APAM@CPGMAs system was developed to facilitate retention and drainage, achieving 20–30 % higher drainage efficiency, 10–15 % higher filler retention, and enhanced sheet strength than the CPAM/SiO 2 /APAM@CPGMAs system. This system holds prospects for environmentally friendly, efficient, and high-quality papermaking.