XPS was used to analyze the chemical composition on the
UHMWPE fiber surface. Fig. 3 shows the XPS survey spectra of asreceived
and potassium permanganate treated fibers. The amount
of oxygen increases and carbon inversely for the treated UHMWPE
fibers. Table 1 shows the O 1 s/C 1s ratio obtained from the XPS
survey spectra. It is seen that the ratio of as-received fibers is 0.031.
M. S. Silverstein et al. [19] discussed the origin of oxygen on asreceived
fibers. They thought the oxygen on the surface was more likely to originate in oxidized low-molecular-weight fragments
excluded during the crystallization process. If the oxygen was
simply spinning oils that remained on the surface then rinsing the
fiber should remove the oil from the fiber surface. The ethanol
rinse, however, did not change the surface oxygen content. The O
1s/C 1s ratio rises rapidly to 0.563 after modification. This rise in
surface oxygen is due to the increase of O-containing groups.