The incorporation of ALK into the silica-filled NR
compound reduced the viscosity of the compound and
facilitated a relatively strong interaction between the ALK
and the silica filler, while the silica particles had a weaker
tendency to interact with each other and form a filler-filler
agglomeration. Consequently, the processability of the silica
dispersion in the rubber phase became easier and
increased the degree of silica dispersion.