INTRODUCING BIOBASED NONPOLAR BOTTLEBRUSH β-MYRCENE SEGMENTS TO IMPROVE SILICA DISPERSION FOR SUSTAINABLE SSBR/SILICA NANOCOMPOSITES

ABSTRACT To overcome the problem of fossil fuel depletion and associated environmental issues arising from the use of tire tread elastomers, a convenient, environmentally friendly, and highly efficient strategy was developed to prepare high-performance green solution polymerized styrene–butadiene rubber (SSBR)/silica nanocomposites by improving silica dispersion in the nonpolar polymer matrix via the introduction of a biobased nonpolar bottlebrush segment with two double bonds. Various elastomers containing biobased nonpolar bottlebrush β-myrcene segments were synthesized using an industrially robust anionic polymerization method. Results of rubber process analysis, small-angle X-ray scattering, scanning electron microscopy, and transmission electron microscopy revealed that rubber with myrcene could significantly improve silica dispersibility and inhibit the strong filler–filler interactions, which are due to the formation of hydrogen bonding between the double bonds in the myrcene block and silanol groups on the silica surface and possibly to the spreading or infiltrating of myrcene bottlebrush segments onto silica. Furthermore, for the modified rubber, rolling resistance decreased by 41.7%, tear strength increased by 20.78%, and tensile strength increased by 77.8% with the elongation at break remained practically unchanged as compared with the unmodified silica/SSBR composite. On the basis of aforementioned assessment, we believe that silica-reinforced β-myrcene–based styrene–butadiene integrated rubber is a versatile and promising candidate for future tire tread elastomers.