Effect of phase selective wetting of hybrid filler on the self-healing properties of rubber blends

Abstract In the present work, self-healable rubber blends consisting of modified bromobutyl rubber (BIIR)/natural rubber (NR) blends filled with silica (Si)/carbon nanotube (CNT) hybrid filler were prepared as model system. It was found that an addition of a low loading of silica as secondary filler for CNTs significantly enhances the tensile strength of the BIIR/NR blends while maintaining the self-healing properties. The synergistic effect of the hybrid filler on the mechanical properties of BIIR/NR blends can be explained by taking into account the selective wetting of the hybrid filler. Thus, a new method based on the wetting concept has been further developed for quantification of the selective wetting of hybrid filler in the BIIR/NR blends. The migration of silica to the BIIR/NR interfacial region and preferential location of the CNTs in NR phase may impart the BIIR/NR blends better mechanical performance and high electrical conductivity. The BIIR/NR blends filled with hybrid filler Si/carbon black (CB) were prepared as reference system. Its similarities and differences with the model system were discussed regarding the selective filler wetting and localization.