Abstract: By means of small angle X-ray scattering, the fractal dimension D for carbonfiber nanometer micropore inner surface is studied. The results show that the size of the carbon-fibers obtained at different carbonification temperatures varies from 1.6 nm to 4.13 nm. And as the carbonification temperature goes up from 900 ℃ to 2 400 ℃, the value of D also goes up from 2.09 to 2.59. When the carbonification draft ratio is enlarged, the micropore fractal dimension will increase somewhat. By determining the mechanical intensity of the carbon-fibers which have different fractal dimension, it was found that those samples which have lower fractal dimension possess larger stretch intensity and condensation intensity.

Key words: small angle X-ray scattering, carbon-fiber, nanometre micropore, fractal dimension, mechanical intensity