The terpolymer of neodymium‐catalyzed styrene,isoprene, and butadiene: Efficient synthesis of integral rubber containing atactic styrene–styrene sequences and high Cis‐1,4 polyconjugated olefins

The present study focuses on the terpolymer of styrene (St), isoprene (Ip), and butadiene (Bd) synthesized together in cyclohexane at 70°C with neodymium (Nd) compound, alkylaluminum, and chlorinating agent (Cl) rare earth cocatalyst system. The resultants possessed atactic St–St sequences and high cis‐1,4 polyconjugated olefins in macromolecular chains besides controllable composition. The composition of the St–Ip–Bd terpolymers and molecular weight (M_w), molecular weight distribution (M_w/M_n) were controlled through the adjustment of Nd compound, alkylalumium, monomers feed ratio (St/Ip/Bd), and Nd]/monomers]. With the inventory rating of St raised from 15% to 55%, the content of St in the terpolymers got increased from 2% to 15%. And the content of the Ip segments and Bd segments in the terpolymers increased from 33% to 56% and from 28% to 54%, respectively, with the proportion of Ip/Bd varied from 1/2 to 2/1. As the Nd]/monomers] varied from 1.0 × 10^?3 to 5.0 × 10^?4, the molecular weight increased from 1.3 × 10⁴ to 2.7 × 10⁴. According to the proton nuclear magnetic resonance (¹H‐NMR) and ¹³C‐NMR, it was proved that both microstructures of polybutadiene segments and polyisoprene segments were high cis‐1,4‐configuration. A single glass‐transition temperature was observed in the differential scanning calorimetry curve. POLYM. ENG. SCI., 54:1858–1863, 2014. © 2013 Society of Plastics Engineers