Application of molecular distillation technology in purifying of PPO-PTHF-PPO copolyether

The polypropylene oxide-polytetrahydrofuran-polypropylene oxide (PPO-PTHF-PPO) copolyether was synthesized with polytetrahydrofuran glycol (PTMG) as the macroinitiator. The remnants of polytetrahydrofuran are difficult to separate by the general purification methods. According to the characteristics of molecular distillation, PPO-PTHF-PPO copolyether was purified by the molecular distillation technology. The results show that molecular distillation can effectively remove the oligomer and small molecules in the copolyether. The operation parameters include: vacuum degree of 0.1 Pa, rotating at 200 r/min, heating temperature of 180°C and two operations. The purity of copolyether increases to 99.95% after purification, the molecular weight distribution reduces to 1.57. It could be applied directly to the polyurethane production without drying.