VAPOR-GROWN CARBON-FIBERS FROM BENZENE PYROLYSIS

Carbon fibers were grown on alumina substrates by vapor phase decomposition of benzene in the presence of hydrogen in a tubular reactor. The effect of lengthening duration and temperature on the average fiber length was studied at two different benzene concentrations (13.2 and 18.6 mol%). In the temperature range (1283-1353 K) investigated, the maximum average fiber length increased with an increase in temperature. At a constant temperature, the average fiber length initially increased with duration of lengthening, and finally reached an asymptotic value. The fiber lengths were unaffected by thickening. A two-parameter model can satisfactorily explain the observed variation in average fiber length with duration of lengthening.