To enhance fibers/matrix interactio

To enhance fibers/matrix interactions, the whole fibers were
subjected to a chemical treatment to bleach and clean their surface
[20–22]. Crushed fibers are first washed thoroughly with water
then kept for 48 h in a 1.6 mol/l sodium hydroxide aqueous solution
[23]. The fibers are then removed from the caustic solution
and quickly treated with acetic acid (100 ml) to neutralize the
remaining caustic [24], after which they were air-dried for 24 h.