Vulcanization with vegetable oils: Quantitative structure-activity relationships and qualitative analysis

Abstract

Vulcanization of styrene-butadiene copolymer (SBR) using stearic acid and vegetable oils of peanut, coconut and linseed was evaluated. With support of the semi-empirical method AM1 (Austin Model 1), molecular modeling was implemented to obtain quantitative structure-property relationships relating estimated molecular descriptors for oils and rheometric parameters determined at 150°C such as minimum torque (S'_l), maximum torque (S'_h), scorch time (t_s1) and optimum cure time (t₉₀). Using multivariate analysis, equations were obtained with excellent values ??of r² (adjusted) and r² (predictor). However, it was found that the chemical complexity of vegetable oils did not allow proposed simplification of individual hypothetical “molecules”. In this way, mathematical models were unable to accurately reproduce experimental data obtained. Thus, best way to address the effect of vegetable oils as activators in the vulcanization of the SBR is through a qualitative view of the descriptors.