Preparation of hydroxyl-terminated polybutadiene via oxidation-reduction method using alcohol catalysts

Conventional methods for synthesizing hydroxyl-terminated polybutadiene (HTPB) with high cis-1,4 content typically involve multi-step oxidation-reduction processes, hindered by poor solubility of sodium borohydride in low-polarity solvents, resulting in low efficiency during the reduction of aldehyde-terminated polybutadiene. A one-pot synthesis approach that incorporates alcohol catalysts to enhance reduction performance is presented in this study. The study results show that ethanol significantly improved reduction efficiency, achieving near-complete conversion of carbonyl to hydroxyl groups within 15 minutes at 30 oC. The resulting HTPB possessed a cis-1,4 content of approximately 95%, with a molecular weight of ~4,880 g.mol-1, a hydroxyl value of 0.78 mmol.g-1 and a glass transition temperature of Tg = -92.1 oC.