Thermal behaviour of poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilon-caprolactone) tri-block copolymers

Thermal behavior of poly(epsilon -caprolactone)-poly(ethylene glycol)-poly( epsilon -caprolactone) tri-block copolymers with different block lengths is examined. Thermal behavior of specimens crystallized under the isothermal and dynamic condition are characterized by DSC. Also WAXD and SAXS are empl oyed to investigate the structure. Depending on the relative length of each block, tri-block copolymers can be classified into three groups: PCL domin ant crystallization; PEG dominant crystallization; and the competing case. When the crystallization of PEG and PCL are competing, the crystallization of each block shows strong dependency on the thermal hystory of crystalliza tion, leading to multiple melting and crystallization peaks. Also, the typi cal micro-phase separation of block copolymers seems to play an important r ole, competing with crystallization, especially under the dynamic crystalli zation condition. (C) 2001 Kluwer Academic Publishers.