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

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), H-1 nuclear magnetic resonance (H-1-NMR) spectroscopy, and C-13 nuclear magnetic resonance (C-13-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.