The Use of Twin Screw Extruder Instead of Model Screw Device During Bamboo Chemo-mechanical Pulping

Abstract

Bamboo is one of the most important raw materials for pulp and paper production in several countries due to its abundance and cost-effectiveness. However, the difficulties in bleaching and low brightness of bamboo chemo-mechanical pulp (CMP) has limited the expansion of its utilization. In this study, the low-cost twin-screw extruder (TSE) was used instead of the high-cost common extruded model screw device (MSD) before chemical impregnation to improve the brightness of the bamboo CMP. There were minor differences in the holocellulose, lignin, and pentose contents in the extruded materials between the two devices. The absorbency of the TSE extruded materials was 4.50 g/g, which was three times that of the material extruded by MSD. Alkali optimization was conducted at levels of 12% H2O2. The TSE-CMP achieved the highest brightness, at 57.6% ISO with 6% sodium hydroxide (NaOH), while the MSD-TMP only reached approximately 49.6% ISO with 3% NaOH. At the same time, the physical properties of paper-sheets made from bleached TSE-CMP and MSD-CMP were tested. When bleached at 12% H2O2 with 6% NaOH, the tensile index of TSE-CMP was higher compared with that of MSD-CMP, while the other strength properties were nearly unchanged.