and the SEM
micrographs of the silica-filled NR vulcanisates. The
micrograph of D/5.0 exhibits a homogeneous micro
dispersion of silica as a result of the incorporation of ALK.
According to Hamed [25], in order for a filler to give significant
reinforcement, the size of its particles must be
small (1 mm) and well dispersed in the rubber matrix. The
deterioration of those properties after 5.0 phr can be
attributed to the lower degree of crosslink density and the
more pronounced softening effect of the excessive ALK