Vulcanization with Natural Products: An analysis through of Molecular Modeling

Abstract

In this investigation, experimental data of natural rubber (NR) and styrene-butadiene copolymer (SBR) rubber vulcanization with vegetable oils, peanut, coconut and linseed, in addition to beeswax, were validated through the molecular modeling of the main reactions of the process. Semi-empirical method AM1 (Austin Model 1) showed that the reduction in hardness, associated with solubility in the elastomeric matrix, is the factor that allows unsaturated fatty acids of 12 or more carbon atoms to act as activators in association with zinc oxide. However, steric impediment makes lignoceric acid, present in beeswax, a low performance activator. For the 18-carbon unsaturated fatty acids present in peanut and linseed oils, unsaturation increases the reactivity of the species generated during vulcanization. However, such a change in nature has an adverse effect, because probably induces side reactions that compromise the activating role of oils.