Elastomeric Nanomaterials Based on Natural Rubber for the Food Industry

This paper presents the obtaining and characterization of new elastomeric nanocomposites based on natural rubber reinforced with plasticized starch, precipitated silica and layered clay, for obtaining consumer goods for the food industry. Obtaining nanocomposites was carried out by the technique of mixing and melt interleaving. The mixtures were vulcanized in the press, at high temperatures, using peroxides as vulcanizing agents, and triallyl cyanurate as vulcanizing coagent. In order to obtain products with improved characteristics, the influence of the amount of modified organic montmorillonite layered clay (OMMT) Nanomer I31PS and the adhesion promoter between mineral filler and polymer - bis-[3-(triethoxysilyl)-propyl]-tetrasulfane (TEPS) on the characteristics of the mixtures, was analysed. The rheological characteristics of the samples show an increase of the minimum torque at the increase in the amount of OMMT type nanofiller and a decrease in the optimal vulcanization time by adding the adhesion promoter between the rubber and the filler. An improvement of the mechanical characteristics of the samples was observed at the introduction of both OMMT and TEPS. These changes may be due to both the nanofiller reinforcement effect and the changes in the morphology of the mixture. The samples showed a good behaviour after immersion in different environments specific to the food industry (water, ethyl alcohol, 10% glucose solution, 0.9% sodium chloride solution and sunflower oil). SEM analyses indicate that the starch particles, together with the other ingredients of the mixture, are quasi uniform distributed in the elastomer matrix. Several superficial microcracks are observed, on the surface of the analysed material, without structural discontinuities or other defects.