On the Silanization Kinetics and Compound Properties of Silica-Filled Rubber Containing a Blocked Mercapto Silane

The silanization kinetics of silica compounds containing a blocked mercapto silane, octanoylthio-1-propyltriethoxysilane, were followed by measuring the suppression of silica flocculation upon heating.  Compounds were prepared with various mechanical and thermal histories by adjusting the mixing time and temperature.  A time-temperature superposed silanization master curve was constructed to evaluate the degree of silanization with the desired compound properties.  Dynamic hysteretic properties at 0^oC and 60^oC in conjunction with strategic mechanical properties were correlated with the degree of silanization for each compound.  Well-balanced properties in processability, reinforcement, and performance were readily attained through the study of the silanization/structure/property relationship. Experimental data showed that 84% degree of silanization was needed to attain the optimal compound properties regardless mixing protocol.