Accelerated retting cum softening of coconut fibre

• Accelerated retting of coconut fibre was performed using Na2S, NaOH and Na2CO3.
• Process reduces conventional retting time from 6 to 12 months to 2 h.
• Chemical retting reduces fibre diameter (35%) and flexural rigidity (72%).
• FTIR, XRD, TGA, component analysis show enhancement in cellulose content in fibre.
• Combined physicochemical and biological methods were used for effluent treatment.

Accelerated chemical retting of raw coconut fibre was attempted. The treatment of raw coconut fibre with a combination of sodium sulphide, sodium hydroxide, sodium carbonate, reduce retting time from 6 to 12 months to 2 h. Chemical treatment decreases the linear density (about 36%), diameter (about 35%), and flexural rigidity (about 72%), ultimately resulting in much softer fibre. The treatment showed positive result towards mechanical proprieties. Fine structure analysis of the treated fibres through FTIR, XRD, TGA, SEM and component analysis validates the beneficial modification with improved properties. The chemical constituent, FTIR and TG analyses revealed enhancement of cellulose content and reduction in lignin, hemicelluloses etc. Resultant crystallinity index of the treated coconut fibre is enhanced by 36% compared to the raw fibres. SEM showed that chemical retting is most efficient in removal of impurities. The effluent obtained from chemical retting was suitably treated to make it safe for discharge.