Avaliação da influência da mistura de elastômeros nas propriedades físico-químicas e mecânicas de formulações elastoméricas

Abstract

This study aimed to evaluate the influence of the mixture of different polymers such as natural rubber ((poly(cis-2-methyl-buta-1,4-diene)) (NR), styrene-butadiene copolymer (poly(buta 1,3-diene-co-styrene)) (SBR) and polybutadiene (poly(cis-buta-1,4-diene)) (BR), on the physicochemical and mechanical properties of elastomeric formulations. Six formulations were performed, varying the polymers used, and making different mixtures between them. The unvulcanized formulations were characterized by rheometric and rheological tests. The vulcanized formulations were evaluated by dispersion properties, differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMA), scanning electron microscopy (MEV), tensile and tear strength (before and after accelerated aging), abrasion wear, hardness, resilience and swelling in solvent (before and after aging). The results obtained were compared between the formulations developed. The glass transition temperature (Tg) results obtained indicate that the NR/SBR and SBR/BR elastomeric blends are immiscible, and the NR/BR blend is miscible. The formulation with NR/SBR showed better results in terms of tensile and tear strength. In the abrasion wear test, the SBR/BR formulation showed the best performance. After the accelerated aging the SBR/BR formulation showed the best results of tensile strength properties, while the NR/BR formulation showed better results of tear resistance. For the solvent swelling test, the SBR/BR formulation showed a lower percentage of swelling and, consequently a higher amount of crosslinking. The results obtained indicate the both the miscibility and the immiscibility presented by the studied blends did not influence the results of the evaluated properties, since the blends presented intermediate results to their respective pure polymers. [resumo fornecido pelo autor]