Microscopic Observation of Aging of Silica Particles in Unvulcanized Rubber

The dynamics of silica particles in unvulcanized rubber is investigated by X ray photon correlation spectroscopy (XPCS) The results show the aging behavior of the dynamics, the dynamics of particles slows down as the aging time increases This slowing down is not accompanied by a change in the configuration of aggregates in size scales of micrometers and sub micrometers The aging behavior depends on the type of silane coupling agent and the volume fraction of silica particles, while it does not originate from vulcanization This study shows that complex microrheological phenomena occur even in industrial products The relationship between these microrheological phenomena and macroscopic viscoelasticity is an open question