2.2. Surface treatment of fi bers
The UHMWPE fi bers were treated by KMnO4 solution and the
solution was a compound of KMnO4 and HNO3 (weight ratio is
1:30). UHMWPE fibers were immersed in the KMnO4 solution for
about 1 min at room temperature and then rinsed with distilled
water several times until a constant pH was reached. The treated
fibers were finally dried in a vacuum oven under around 0 Pa at
room temperature for 12 h