In order to improve the dispersibility of carbon black (CB)

natural rubber (NR) degraded under high temperature and powerful shear force was grafted onto the CB surface by in situ solid state grafting method.The morphology of original CB and grafted carbon black (GCB) particles was investigated by transmission electron microscope (TEM) and atom force microscope (AFM).The results showed that original CB particles fused together and presented as big dendritic agglomerates whose size was several microns

while the size of GCB particles diminished greatly and displayed as small aggregates of about 200 nm

which was because the aggregates of original CB were partly broken by powerful shear force and at the same time the degraded NR molecules was grafted onto the newly CB surface which prevented CB particles from aggregating again.The particle size of original CB and GCB was measured by using a laser light scattering particle sizer.The volume particle size of GCB was 164 nm which was largely less than that of original CB

797 nm.The dispersion and dispersion stability of original CB and GCB were determined with sedimentation

ultraviolet spectrophotometer and zeta potential measurement.Compared with original CB

the dispersion of GCB in the solvent of grafted molecules became better

moreover

the dispersion stability of GCB also was improved.