Influence of the concentration and temperature of Hypochlorite on the properties of Pulp derived from Sesbania grandiflora

Bleaching is a process to brighten the pulps but also enhance the cleanliness of pulp by removing the bark fragments and eliminate the colour reversion. Previous research discovered that high dioxins and furans content from the bleach plant effluent originated from chlorine gas which resulted in the water pollution and human carcinogen. Therefore, in this project, sodium hypochlorite was used as the bleaching agent to brighten the pulp derived from Sesbania grandiflora. The purposes of this project were to evaluate the effectiveness of hypochlorite in removing lignin content from the Sesbania pulp and investigating the influence on the physical and strength properties on Sesbania pulp. Six types of bleaching condition were used to bleach the Sesbania pulp. Bleaching conditions were controlled, 2.5wt% and 5.0wt% of sodium hypochlorite solution (NaC10) under 25°C and 50 °C. The evaluations were conducted accordance with TAPPI standard. 5.0wt % of NaC10 solution under 50°C was the effective condition which showed the highest on brightness and the least of lignin content compared the others. However, the overall of strength properties is decreased due to the fibre degradation.