| abstract |
Pitch-based graphitized short fibers formed from mesophase pitch as a raw material, having an average fiber diameter of 5 to 20 μm, a percentage (CV value) of a variance of a fiber diameter with respect to the average fiber diameter of 8 to 15%, a number average fiber length of 20 to 500 μm, and a crystallite size (La) derived from a growth direction of a hexagonal net plane of 30 nm or more, having graphene sheets that are closed upon observation of an end surface of a filler with a transmission electron microscope, and a substantially flat surface observed with a scanning electron microscope, and having an R value, which is a relative intensity ratio (I D /I G ) of an intensity (I D ) of a Raman band in the vicinity of 1,360 cm −1 to an intensity (I G ) of a Raman band in the vicinity of 1,580 cm −1 measured by laser Raman spectroscopy, in a range of 0.01 to 0.07. The short fibers can be filled in a rubber composition at a high density without inhibition of curing of the rubber composition. |