accelerate the vulcanization reaction18–20 and hence
there is a reduction in cure time. Consequently, the
scorch time is also low for modified silicate-incorporated
compounds compared to the others. The MH–
ML value, which is a measure of the viscosity of the
compound, is comparatively high for the modified
silicates. Mooney viscosity is also high for the modified
silicates. The scorch time obtained from the
Mooney viscometer also showed a reduction with the
addition of MMT-ODA and MMT-TMDA. The high
Mooney viscosity is an indirect indication of intercalation
of the polymer into the layered silicate layer.
This shows that the rubber molecules underwent
intercalation because of the high shear force generated
during mixing. Because of this interaction process,
the surface area of the layered silicate increased,
which might be the reason for the high compound
viscosity.