| 초록 |
Improvement of properties in polyurethane block copolymers was investigated by controlling the soft segment distribution. Two kinds of polyurethane were synthesized by prepolymerization method and using high and low MW PTMGs: a random distribution of soft segment and a di-block type distribution. Tensile properties of samples were influenced by the prepolymerization method and the composition of high and low MW PTMGs. It seemed that the difference in soft segment distribution, rather than the phase separation between hard and soft segments, was responsible for the result. It was found that shape recovery, which was obtained by analyzing thermomechanical relation between stress and strain at various temperature, increased with increasing amounts of high MW PTMG. On the other hand, glass transition behavior also depended on prepolymerization method and mole ratio of PTMGs. |
