Ref.: MpoBel01-001
Apresentador: Gabriel Bachega Rosa
Autores (Instituição): Rosa, G.B.(Instituto Tecnológico de Aeronáutica / Instituto de Aeronáutica e Espaço); Mello, S.A.(Instituto de Aeronáutica e Espaço); Cassu, S.N.(Instituto Tecnológico de Aeronáutica / Instituto de Aeronáutica e Espaço);
Resumo:
Elastomeric adhesives find extensive applications in challenging environments, encompassing rigorous thermal, mechanical, and chemical conditions. Within this category, polychloroprene adhesives stand out as a crucial component, particularly renowned for their prevalence in the aerospace industry. These adhesives work by establishing a bond between two surfaces, employing mechanisms such as chemical bonds, intermolecular forces, or electrostatic attraction. Although its properties are excellent, it still uses several highly contaminating components in its usual formulations, such as toluene and zinc oxide. With this in mind, the aim of this study was to replace zinc oxide and minimize the use of toluene, replacing them with less aggressive compounds, with ferric acetylacetonate (FeAc) as the vulcanizing agent and methyl ethyl ketone as the solvent. This work also focuses on enhancing the material properties by examining the use of fumed silica, a filler with theoretical nanometric dimensions. The study investigates varying amounts of silica ranging from 2 to 6 parts per hundred rubber (phr). For comparative analysis, a compound containing approximately 10 phr of precipitated silica and Zinc Oxide (ZnO) as the vulcanization agent and toluene as solvent was used as the reference material. The rheometric findings reveal that compounds vulcanized with FeAc exhibit a higher torque value compared to those vulcanized with ZnO. As the silica content increases, the torque values also rise, indicating a higher degree of cross-linking in the material. In the peeling tests conducted post-vulcanization, the 145°C/6h condition emerges as the optimal configuration, yielding the most favorable overall results. Compounds with higher silica contents exhibit increased resistance to peeling under this condition. It's noteworthy that, despite these positive trends, the compound containing a curing system based on ZnO still outperforms others in terms of peeling resistance. DSC analysis indicates the presence of a crystalline phase in the material, in which the greater the amount of silica incorporated, the more pronounced the presence of the crystalline phase becomes in the material. From the results obtained, it can be concluded that the substitution of aggressive compounds shows good results under the conditions studied, coming very close to the results obtained for the adhesive based on ZnO and toluene.