Preparation, carbon black dispersibility and performances of novel biobased integral solution-polymerized styrene–butadiene rubber with β-myrcene bottlebrush segments

A series of green myrcene-based styrene–butadiene integral rubber were designed and prepared by anionic solution polymerization for solving the fossil depletion and achieving the excellent comprehensive performances, including SBR (75) + MR (25), r-SBMR, b-SBMR and s-b-SBMR. The RPA, SAXS, SEM and TEM results revealed that flexible side chain in myrcene bottlebrush segments, which was beneficial to spread and infiltrate on the surface of the filler, could significantly improve carbon black (CB) dispersibility and inhibit the strong filler–filler interactions. The degree of improvement in CB dispersibility can be ranked as follows: SBR (unmodified rubber) < SBR (75) + MR (25) (mechanical blending rubber) < r-SBMR (26) (random copolymerized rubber) < b-SBMR (26) (block copolymerized rubber) < s-b-SBMR (26) (star block copolymerized rubber). Furthermore, for the star-shaped integral rubber, rolling resistance decreased by 40.2%, wet skid resistance increased by 74.8%, and elongation at break increased by 8.30% without sacrificing the physical and mechanical properties compared with the unmodified SSBR/CB composites. The results show that the chain segment of the bottlebrush structure has reasonably obvious advantages over than that of the random distribution structure in improving the dynamic mechanical properties of rubber. On the basis of aforementioned assessment, we believe that CB-reinforced β-myrcene-based styrene–butadiene integrated rubber is a versatile and promising candidate for future tire tread elastomers.