Effects of Alkali-urea Pretreatment on Properties of Moso Bamboo (Phyllostachys pubescens) Mechanical Pulp

This work proposed a chemical pretreatment using a NaOH-thiourea aqueous solution at -5°C for modifying properties of a high yield mechanical pulp from moso bamboo (Phyllostachys pubescens). The effects of alkali dosage, of soaking time and of the following chilling time on the bamboo chips were evaluated. The optimal conditions were chosen as alkali dosage of 6%, soaking time of 15 min, and chilling time of 60 min. The refining energy of the bleached chemi-mechanical pulp was reduced by the chemical pretreatment using NaOH-thiourea aqueous solution, and further the screened yield, the brightness and the strength properties of the pulp were higher than those of the bleached mechanical pulp. However, there were no significant differences in the analysis of XRD and SEM between the NaOH-thiourea aqueous treated mechanical pulp and two bleached mechanical pulps.