Mechanical properties, dynamic mechanical analysis and molecular cross-linking of GTR/NR re-Vulcanized blends

• Published in: Progress in rubber, plastics and recycling technology Vol. 38; no. 4; pp. 280 - 294
• Main Authors: Zitzumbo, R, Alonso, S, Estrada-Monje, A, Becerra, María B, Avalos, F, Medina-Torres, L
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01-11-2022; Sage Publications Ltd
• Subjects: Carbon black; Chain dynamics; Charts; Crosslinking; Density; Dynamic mechanical analysis; Experiments; Free radicals; Heterogeneity; Mechanical properties; Mixtures; Molecular motion; Natural rubber; Recycling; Rubber; Solvents; Tensile strength; Thermodynamic properties; Tires; Toluene; Vulcanization; GTR/NR blends; natural rubber; DMA; cole-cole charts; Ground tire rubber
• ISSN: 1477-7606; 1478-2413
• DOI: 10.1177/14777606221127370

The effect of natural rubber (NR) on mechanical, chemical and thermal properties of ground tire rubber (GTR) was investigated. Mechanical and thermal properties of GTR/NR vulcanized blends were determined with a universal testing machine and a dynamic mechanical analyzer (DMA). The molecular cross-linking density was determined by molecular swelling in toluene. Presents results indicate that the carbon black embedded in the GTR interior phase of the GTR/NR re-vulcanized blends, did not participate in the NR phase molecular motion restriction. The blends of GTR/NR showed the phenomenon known as reversion, leading a decreasing of the mechanical properties, that could be attributed of the degradation of the interphases (GTR/NR) n+j, j=1,2,3,…. On the other hand, the Cole-Cole charts of the GTR/NR vulcanized blends changed from a semicircular to an irregular form as the NR concentration increases, imposing the heterogeneity of the blend. In addition, in the Cole-Cole charts of GTR/NR vulcanized and re-vulcanized blends, the height (
E´´
) and the width (
E´
) of the curves decreased while the re-vulcanization processes number was greater; obtained results could be attributed to the increasing of the molecular cross-linking density.