Effect of Chemical Modification of Solution-Polymerized Rubber on Dynamic Mechanical Properties in Carbon-Black-Filled Vulcanizates

Abstract

Abstract From the Part I experiments, n-butyl-EAB shows a strong interaction (chemisorption) with the carbon black surface. The chemical structure of chemisorbed n-butyl-EAB is similar to that of the component, with a peak at 290 nm. The EAB groups of the chain-ends in the modified polymer enhance the adsorption of the polymer onto CB-N, because of a chemisorption by the EAB groups. We estimate that the reaction mechanism of chemisorption is an acid-base reaction and that SBR-EAB has a conformation somewhat rising in the radial direction on the CB-N surfaces. From the Part II experiments, the saturated adsorption of n-butyl-EAB or the chemically-modified polymer prevents the agglomerate-growth of carbon black and enhances the dispersion stability of the carbon black dispersed in a nonpolar solvent such as benzene. From the Part III experiments, the chemically-modified rubber absorbed strongly onto the CB-N surface enhances the dispersion stability of the carbon black in vulcanizates, and, hence, suppresses the transient-structure formation or network formation of carbon-black-carbon-black particles. The reduction in the transient structure decreases the dynamic-shear modulus at low strain amplitude and, hence, decreases the loss modulus maximum G″max, causing the increase of rebound resilience.