Abstract
Spherical silicas of different specific surface area (1 to 700m2/g), of different perticle size (4 to 30μm) are prepared by sol-gel method.
Apparent densities, oil absorptions, the number of silanols, pore size distributions, and equilibrium water contents are investigated.
Bound rubbers in SBR are also studied. It is considered that bound rubber are formed in case of spherical silicas of over 400m2/g and of under 20μm. By SEM observation, theae spherical silicas disperse to submicron particles and are enterwined with SBR molecules. On the other hand, silicas of low specific surface area, low absorption of oils or large particle size are formed no or little bound rubbers.
