The raw coconut sheath fibers were washed several times with water for the complete removal of plant debris and dried at room temperature for 24 h. After this, the coconut sheath fibers were immersed in 5% sodium hydroxide solution for an hour and then neutralized with 5% acetic acid solution [11]. Finally, the treated coconut sheath fiber was dried at 110 °C for 1 h and used as a reinforcing material for polymer composites.