The Sulphate Removal via Post Alkaline Treatment on Nanocrystalline Cellulose with Different Lignin Content Extracted from Kenaf Core

Abstract

The production of nanocrystalline cellulose (NCC) usually takes place through a series of chemical processes like pulping, bleaching and acid hydrolysis process. The hydrolysis processes using strong acid like H2SO4 can help the NCC to have a high degree of crystallinity and imparts a negative surface charge to NCC. However, the application of H2SO4 leads to increment in dehydration reaction and lowered the NCC thermal properties. Post alkaline treatment is the method that is commonly used to recover the effect of H2SO4 by neutralizing the acid using a strong base like sodium hydroxide (NaOH). On the other hand, the effect of lignin in fibres was able to help in improving the thermal properties and extraction of lignin was seen involving an excessive number of chemicals. The lignin part can remain in the pulp by controlling the bleaching process. Therefore, in this study, NCC with different lignin content went through post alkaline treatment to remove the remaining sulphate groups. The thermal analysis revealed that the existence of lignin and removal of sulphate groups help to increase the thermal stability of the NCC by shifting the degradation and melting temperature to the higher value.