Applications of cationic bamboo fibers for the effective reinforcements of secondary fibers

Bamboo, with its long fibers, fast growth, high abundance, and short harvesting cycle, is a promising alternative to traditional wood pulp, particularly in reinforcing secondary fibers during paper recycling. In this study, different from direct addition with poor combination concerning the negative charge in recycled pulp fibers, bamboo fibers were firstly modified with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) to get cationic bamboo fibers, the characterizations by FTIR and N contents (maximum 1.05 %) classified that the hydroxyl groups in bamboo fibers were etherified effectively with greater zeta potentials (maximum −13.2 mV) in mixed pulps. The cationic modification of bamboo fibers resulted in a significant increase in the tensile and burst index of the secondary pulp, by 49.75 % and 61.54 % with only 10 %addition, respectively, as compared to the unmodified bamboo fibers, which was contributed to the mutual attraction between positively charged modified bamboo fibers and negatively charged secondary fibers, besides the original hydrogen bonding inside fibers, which leads to the enhancements for secondary fibers strength. These findings provide valuable insights into the effective applications of bamboo fibers for reinforcing recycled paper and offer promising solutions for the sustainable development of the paper industry.