Response of partial substitution of MgO for NaOH as the alkali source in hydrogen peroxide bleaching to properties of triploid poplar chemi-thermomechanical pulp.

Given the current scarcity of wood fiber resources, it is imperative to investigate the potential of employing weak alkaline hydrogen peroxide for bleaching high-yield pulp (HYP) to meet the increasing demands for paper and paperboard. This work presents an investigation into the characteristics of triploid poplar chemi-thermomechanical pulp (CTMP) hydrogen peroxide bleaching, including the brightness, bleaching yield, bulk, physical strength, and contents of carbohydrates and lignin. The findings show that partial substitution of MgO for NaOH as an alkali source could improve the yield and bulk of the bleached CTMP. When the substitution ratio of MgO for NaOH reached 75 %, the brightness of 74.62 % ISO for the bleached pulp dropped by only 0.47 percent points but the bulk of 2.21 cm3/g increased by 5.74 % compared to those of the control, respectively. Meanwhile, the yield of the bleached CTMP could reach 93.45 %, 5.07 percent points higher than that of the control. The results would be of benefit to the HYP enterprises concerned. • Substitution of MgO for NaOH fulfilled the criteria for achieving good brightness. • Substitution of MgO for NaOH improved the yield of bleached CTMP and bulk. • Adding MgO increased the content of carbohydrate and lignin in the bleached pulp. • The surface lignin content would increase with raising the ratio of MgO-to-NaOH. [ABSTRACT FROM AUTHOR]