Abstract:The micropores of the rayon based carbon fiber precursors were studied during the pyrolysis process.
Results indicated that the longitudinal radius of the micropores increased gradually from 3. 88 nm to 7. 04 nm while the
evolution trend of transversal radius was inverse which decreased to 3. 15 nm from 3. 86 nm, thus the shape of the mirocpores
became needle. Meanwhile, the fractal dimension of transversal micropores increased from 2. 40 to 2. 61 and
the fractal dimension of longitudinal micropores fluctuated in the process from 2. 00 to 2. 23, which indicated the
roughness of the micropores increased gradually. The micropore is a major factor in controlling the mechanical property
of fibers, therefore it's important to study the micropores.