Amphiphilic Janus nanosheets by grafting reactive rubber brushes for reinforced rubber materials

Abstract

Amphiphilic Janus nanosheets with reactive rubber brushes (PBd-silica-PI) were fabricated by using silica nanosheets as templates and by attaching polyisoprene (PI) and polybutadiene (PBd) brushes onto opposite sides. The compatibility between the attached polymer brushes and the rubber matrix accounted for reduced phase domains, revealing as a bicontinuous structure within the PBd-silica-PI Janus nanosheet filled solution styrene–butadiene rubber/natural rubber (SSBR/NR) blends. Although the silica nanosheet templates themselves could act as a reinforcing agent for the rubber materials, as with most silica, in this case, the amphipathy and the co-vulcanization of the reactive polymer brushes with the native polymer matrix enabled the synchronous strengthening and toughening of the rubber blends. When 3 parts per hundred rubber (phr) of Janus nanosheets were incorporated, the tensile strength of the composites was 3-times higher than that of the SSBR/NR blend on its own, and 2 times higher than that of silica nanosheet filled rubber blends. Additionally, the elongation at break of the composites reached a maximum of 470% compared to the original 320% of the SSBR/NR blends on their own.