VAPOR-GROWN CARBON-FIBERS FROM PYROLYSIS OF HYDROCARBONS - MODELING OF FILAMENT GROWTH AND POISONING

A kinetic scheme has been proposed as a feasible model to explain the lengthening step in vapor grown carbon fibers from the pyrolysis of hy drocarbons. The two-parameter model assumes that the filaments lengthe n by the reaction of a pyrolysis product with the growing filaments, a nd that the growth process ceases when the catalyst particle attached to the growing filament is poisoned by some reactive species in the ga s phase. The model results show that the rate of filament growth is in itially high and decreases monotonically. The final average filament l ength is found to depend only on the ratio of the rate of growth to th e rate of poisoning. The model results can satisfactorily correlate th e limited experimental data available in the open literature.