| 초록 |
Star-shaped oligo(ε-caprolactone)s (SOCLs) were synthesized with controlled architecture of different branch number and length. Viscoelastic properties of SOCLs were analyzed in the temperature above the melting point. Time-temperature superposition principle was applied to all samples, and then the master curves of SOCLs were constructed by superimposing the loss and storage moduli data measured at different temperatures. These master curves were approaching the terminal flow region, where the rubbery plateau region and the crossover were not observed. The flow activation energies were obtained from the Arrhenius temperature dependence of steady shear viscosities, Ea,η, and horizontal shift factors, Ea,aT. Moreover, the horizontal shift factors were fitted by William-Landel-Ferry (WLF) equation. The flow activation energy increased as the increase of branch number and length, indicating that SOCLs with smaller branch number and shorter branch length had higher molecular mobility. |
