| 초록 |
Poly(urethane-co-urea) is one of versatile polymers for automotive parts, cloths, adhesives for concrete and steel as the physical properties of poly(urethane-co-urea) can be varied in a wide range of hardness and mechanical properties. Poly(urethane-co-urea) is derived from the reaction product of an isocyanate terminated polyurethane prepolymer and amine terminated chain extender. Generally, processing of poly(urethane-co-urea) is difficult due to the short gelation time during the chain extension. Herein, we investigated the effect of alkali metal salts in the preparation of poly(urethane-co-urea). The amine terminated chain extender reacts with alkali metal salt such as NaCl to form a crystalline precipitate. Reactivity of amine and isocyanate could be lowered by the complex of amine and NaCl and the gelation during the chain extension was retarded effectively. |
