| 초록 |
Polyisocyanates and their block copolymers have been very interesting and attractive materials due to their helical conformation caused by their stiff amide backbone and steric constraints. In the anionic polymerization of isocyanates, the most problem is the formation of trimer or dimmer due to backbiting. For the last several years, we have studied and found that when 15-crown ether-5 or sodium tetraphenylborate are used as additives in the polymerization of isocyanates, the formation of trimer or dimmer is significantly minimized. To find a new and more effective initiator, we carried out the polymerization of isocyanates using sodium diphenylamine (Na-DPA). Interestingly, we found that Na-DPA is also an effective initiator for the polymerization of isocyanates since it has a key role in the initiation and protection of the living chain-ends. |
