Controlled copolymerization of isoprene and hydroxylmyrcene afforded well-defined hydroxyl functionalized polyisoprene. Blends of functionalized polyisoprene/SiO2 displayed enhanced miscibility, and remarkable vulcanization and mechanical properties.

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Disulfide carbon (CS 2 ) and triphenyl phosphine (TPP) were tested as donors for cobalt (Co1, Co2, and Co3)catalyzed 1,2-syndiotactic polymerization of butadiene. With CS 2 , a 1,2-selectivity of 96.8% and syndiotacticity (rr) up to 97% were achieved by Co1−Co3/Al i Bu 3 /CS 2 , yielding highly crystallized polybutadiene resin. Variations on polymerization temperature (0−80 °C), catalyst loading, and polymerization time did not significantly affect the 1,2-incorporation and syndiotactic conformation of the resulting polymers, highlighting the excellent 1,2-stereoselectivity of active species stabilized by CS 2 . With external donor TPP, the formed Co1−Co3/MAO/TPP have regioselectivities of 65.2−89.2% and syndiotacticities of 32.1−65.5%. Thus, an array of polybutadienes differing in chemoenchainment and 1,2-stereoenchainment is accessible with the present cobalt catalysts in combination with different donors. AFM measurements were performed to distinguish the morphology of two types of 1,2-syn-polybutadiene. Elucidation on the plausible role of CS 2 and TPP in the stereoselective polymerization reaction was also made.