Triethoxysilyl-Terminated Telechelic Liquid Butadiene Rubber with Disulfide Linkages for Tire Tread of Electric Vehicles

The increasing global adoption of electric vehicles (EVs) has shifted the focus of tire research toward enhancing fuel efficiency and abrasion resistance. In this study, we propose triethoxysilyl-terminated telechelic liquid butadiene rubber with disulfide linkages (Si69-LBR) as a processing aid in the tire tread compound to enhance tire performance. The triethoxysilyl groups at both ends of Si69-LBR form covalent bonds with silanol groups on the silica surface, and the disulfide linkages in Si69-LBR additionally cross-link with the base rubber. Si69-LBR was synthesized via a "one-step" process using Si69, containing bis[3-(triethoxysilyl)propyl]tetrasulfide, as an iniferter (initiator―transfer agent―terminator). Compared to the compound applied with 40 phr processing oil, the compound in which 10 phr was replaced with Si69-LBR exhibited enhanced migration resistance, abrasion resistance, and fuel efficiency of 21, 20, and 7%, respectively. These results explain the effect of the functionalization of LBR and the additional cross-linking resulting from sulfide bonds in Si69-LBR.