Stabilization and carbonization properties of mesocarbon microbeads (MCMB) prepared from a synthetic naphthalene isotropic pitch

Carbonization properties and stabilization reactivity of MCMB prepared at a high yield from a particular synthetic naphthalene isotropic pitch with and without carbon black (CB) were evaluated in terms of their fusibility, adhesion ability and graphitizability. MCMB prepared without CB carried much higher hydrogen content which is attributed to aliphatic or naphthenic hydrogens, showing high fusibility when MCMB were further carbonized. Addition of carbon black at preparation decreased the fusibility of MCMB is successive carbonization. Oxidative stabilization decreased naphthenic hydrogens from MCMB to introduce oxygen functional groups, such ester and anhydride groups, inhibiting their deformation. Although MCMB exhibited lower oxidative reactivity than that of the parent isotropic pitch, oxidative stabilization for 60 min at 300°C was sufficient to maintain the spherical shape of MCMB without CB, introducing 8.3 wt% oxygen. Oxidative stabilization was also completed after 120 min at 270°C, introducing 4.7 wt% oxygen. Complete stabilization was achieved by 60 and 30 min at 270°C for MCMB prepared with 1 and 3 wt% BP2000, taking up 3 and 2 wt% oxygen, respectively. It is noted that CB reduced the oxygen uptake necessary for the complete stabilization. Both CB and oxidative stabilization reduced the graphitizability of MCMB.