A novel synthetic strategy for hydroxyl-terminated polybutadiene containing high cis-1,4 contents based on a Ni(ii)-coordinated anionic initiating system

Abstract

In this study, novel hydroxyl-terminated polybutadiene (HTPB) with a high cis-1,4 content was developed using a tert-butyl dimethyl siloxy dimethyl propyl lithium (Li)–naphthenate nickel (Ni)–boron trifluoride (B) initiating system (Li–Ni–B). The effects of the material ratio and the addition sequence on the cis-1,4 content and molecular weight of HTPB were studied, and the results were discussed. The optimal Li/Ni ratio was 10 : 1, and the optimal Li/B ratio was 1 : 2. HTPB prepared by the Li–Ni–B system was characterized by Fourier transform infrared spectroscopy (FTIR), ¹H nuclear magnetic resonance (¹H-NMR) spectroscopy, and ¹³C nuclear magnetic resonance (¹³C-NMR) spectroscopy. The results suggested high cis-1,4 contents in HTPB synthesized using Li–Ni–B (cis-1,4 > 95%). The comparison of the cis-1,4 contents in the HTPB samples obtained by anionic polymerization and the Li–Ni–B system revealed the advantages of the latter compared to the former.