P. Mandal, S. Ponnupandian, S. Choudhury, N. Singha This investigation reports the thiol-ene modification of high vinyl content styrenebutadiene-styrene (SBS) block copolymer (BCP) in toluene at 70 °C using different thiolating agents. 1H NMR analysis confirmed the participation of vinyl double bond in thiol-ene modification reaction of SBS. Surface morphology of the block copolymers evaluated by AFM analysis showed higher roughness after thiol-ene reaction. The thiol- modified SBS block copolymer showed better adhesion strength and oil resistance properties than the pristine SBS.