The hydrophobicity characteristics of soda pulp of rice straw modified with water-soluble chitosan

Rice straw can be an alternative material for producing great pulp and paper also can be produced by several variations of the pulping process. This study was conducted to prepare and evaluate the hydrophobic rice straw pulp soda using atmospheric hot soda (AHSP) and soda (SP) pulping methods and modified with water-soluble chitosan treatment. The pulps were modified with water-soluble chitosan treatment at 1% and 2%. The screen pulp yield, kappa number, and delignification selectivity were analyzed to evaluate the properties of the pulp, while hydrophobicity properties were evaluated by its water absorption capacity and wettability. The FTIR was used to investigate the possibility of a new functional group formation after modification. The screen pulp yield of AHSP (29.22%) was relatively higher than SP (21.94%). However, SP pulp has a lower kappa number with higher delignification selectivity than AHSP pulp. After pulp modification, the hydrophobicity of the modified pulp increases in line with the increasing concentration of water-soluble chitosan. The AHSP pulp with a 2% water-chitosan treatment has the highest hydrophobicity indicated by the lowest water absorption capacity at 60 minutes i.e 41.99%. Therefore, based on hydrophobicity analysis, AHSP and SP modified with a 2% water-soluble chitosan treatment have better hydrophobicity.