Investigating the effects of boron compounds on the cellulose fiber performance in paper recycling process.

This study aimed to investigate the effects of boron compounds on cellulose fibers during recycling. Three recycling stages were conducted, applying boric acid and borax to bleached papers. Physical, mechanical, and optical properties were measured after each process. The highest water absorption (218 g/m²) was observed in test papers from the second recycling stage using 10% borax-treated pulps (10Bx2). Boric acid treatment notably improved burst strength, with the highest value (3.94 kPa m²/g) in the first recycling stage with 5.0% boric acid treatment (5Ba1). The highest tensile strength (49.48 Nm/g) occurred in the first recycling stage with 5.0% boric acid treatment, while the lowest (17.41 Nm/g) was in the second recycling stage (5Bx2) with 5.0% borax treatment. Tear strength exhibited different trends from burst and tensile strength, with notable improvements using 5.0% and 10% boric acid and 10% borax treatments on recovered cellulose fibers. The highest tear strength (9.20 Nm²/g) was achieved with 5.0% boric acid treatment (5Ba2) in the second recycling stage, followed by 8.21 Nm²/g with 10% boric acid treatment (10Ba1) in the first recycling stage. Tear strength trends differed from burst and tensile strength properties, regardless of treatment conditions. [ABSTRACT FROM AUTHOR]