Processing of natural lignocellulosic coir fibres for enhanced flame retardancy using aluminium trihydrate

The high lignin cellulose ratio in coir fibres makes it more susceptible to fire, whereby coir and its allied products are pushed back away from fire retardant applications. These fibres are subjected to treatments by soaking in hot dilute solution of aluminium trihydrate for enhanced fire retardancy. The treated fibres exhibited improved flame retardant properties with reduced water absorption and showed no remarkable change on the physical and mechanical characteristics. The time of burning was significantly reduced from 182 to 65 seconds and the treated fibres did not produce smoke when burnt. The flame propagation rate was reduced by 2.5 times and limiting oxygen index elevated by 1.2 times compared to the raw fibre. As a low toxic, sparingly soluble substance, aluminium trihydrate is a better halogen-free fire retardant addition for coir fibres in product manufacturing in the coir sector.