Randomly Coordinative Chain Transfer Copolymerization of 1,3-Butadiene and Isoprene: A Highly Atom-Economic Way for Accessing Butadiene/Isoprene Rubber
Feng Wang, Mingming Zhang, Heng Liu, Yanming Hu, Xuequan Zhang
Abstract
Through the coordinative chain transfer copolymerization strategy, 1,3-butadiene/isoprene copolymers bearing exactly tunable molecular weights, narrow molecular weight distributions, and precisely controllable compositions are successfully achieved. Approximately 4–6 polymer chains can be produced per molecule of precatalyst Nd(OiPr)3, revealing a higher atom-economic fashion than the traditional living copolymerization strategies. Detailed kinetic studies demonstrated living characteristics for the present system, and copolymer compositions agree well with feed ratios, suggesting the good controlling ability of the catalytic system. The monomer reactivity ratios were determined as rBD = 0.76 and rIP = 0.70, and NMR spectral analysis showed random sequences for the resultant copolymers.