The transition mechanism of dynamic mechanical loss peaks and phase analysis in binary block copolymers of styrene/butadiene rubber

Abstract

Abstract The binary segmented styrene-butadiene rubber (SSBR) have been synthesized using butadiene (Bd) and styrene (St) as monomers through living anionic polymerization. This study investigates the loss peak transition mechanism, phase transition mechanism, and the relationship among structure, phase state, and dynamic mechanical properties of segmented SSBR. The results indicate that the two-segment polymerization method allows for precise control of the sequence structure of binary segmented SSBR. The change in the loss peak of SSBR is continuously observed. The phase structure of SSBR can be altered by adjusting the length ratio of the soft and hard segments, which makes structure transition from phase separation to partial compatibility, and ultimately to full compatibility. Furthermore, the mass ratio of Bd/St within the soft and hard segments can be manipulated to influence the compatibility of the SSBR system. TEM images reveal that the transition from complete phase separation to partial compatibility, and ultimately full compatibility, can be represented by changes in the size and distribution of Bd aggregate particles, transitioning from large-sized, mixed-sized particles to uniformly small-sized particles.