Controllable Preparation of Hydroxyl‐Terminated Liquid Polydiene Rubber Featuring High 1,4‐Content by Neodymium‐Mediated Coordinative Chain Transfer Polymerizations Strategy

Hydroxyl‐terminated polydiene (HTPD) liquid rubber currently finds wide applications in our daily life. Nevertheless, synthesizing HTPD featuring high 1,4‐content, which imparts excellent low‐temperature properties, remains a challenging yet crucial task in this field. In this study, we present a novel and controllable approach for synthesizing HTPD via neodymium‐mediated coordinative chain transfer polymerization (CCTP) of butadiene and isoprene, enabling the production of hydroxyl‐terminated polybutadiene (HTPB) and hydroxyl‐terminated polyisoprene (HTPIp) with 1,4‐contents in ranges of 98.5%–99.0% and 93.9%–99.5%, respectively. The strategy follows a three‐step process: firstly, an OH‐functionalized diene derivative (Bd PhOH ) is introduced during the catalyst aging stage to construct the α ‐terminal OH group; secondly, polymerization proceeds to construct the main chain; finally, the ω ‐terminal OH group is formed via in situ oxidation of the Al‐capped polymer chain with O 2 at the end of polymerization. Additionally, incorporating a small fraction of Bd PhOH during the catalyst aging stage was found to bring little negative influence on the CCTP behavior of the system, allowing the polymerization to proceed in a well‐controlled manner, as evidenced from detailed kinetic studies, and therefore demonstrating an effective method for precise control of the molecular weights of the HTPD products that are also in relatively narrow polydispersities.