| A systematic study of the influence of the in-situ modification of carbon black with amine plasticizers on the properties of peroxide-crosslinked styrene-butadiene rubber (SBR) was conducted. An acidic and a basic black with similar physical characteristics (particle size, surface area, and structure), but different surface character were modified in-situ with two aliphatic amines (octadecylamine and oleylamine). The acidic black, from titration, was shown to possess ten times the number of acid groups compared to the basic black. Nonadecane, containing the same alkyl group as octadecylamine but no functional group, was the plasticizer employed in control compositions. Low levels of plasticizers had little effect on cure and tensile properties of gum vulcanizates, but the storage moduli of compositions containing amine plasticizer decreased sharply with increasing strain (Payne effect). When the acidic black is present, cure is retarded, crosslink density lowered, and bound rubber formed. Reinforcement is substantial. Amine modification neutralizes the black and increases crosslink density. Tensile strength increases with low levels of modification and tan... |
