Modification of pyrolytic carbon black (CBp) was carried out by acid washing (washed carbon black

WCBp) and then added with stearic acid (stearic acid modified WCBp

SWCBp).These three carbon black samples were characterized by using X-ray fluorescence spectroscopy (XRF)

scanning electron microscope (SEM)

X-ray photoelectron spectroscopy (XPS)，etc.The CBp is composed of carbon particles in micron scale containing a large proportion of ash.After acid washing

the ash content decreases from 20.46% to 8.65%.Both the WCBp and the SWCBp have a higher BET specific surface area and a higher volatile content than CBp.As analyzed by XPS

the CBp surface is covered by carbonaceous deposits

which makes the surface polarity decrease and the oil-affinity increase.Upon acid washing and stearic acid modification

part of the polar functional groups is exposed

and there contains more C—OR

C—OEt

COOR/COOH groups in SWCBp.