X-ray diffraction studies of the recrystallization of C_(60)-based polymers

摘要

A time-dependent x-ray scattering study is presented of the kinetics of the C_(60)-based star polymer containing 6 urethane-connected polyether and the star model polymers containing 4, 3, and 2 urethane-connected polyether arms. By varying the temperature from 40°C to -40°C, the order-disorder phase transition (recrystallization) of the polymers has been observed. Two crystalline domains with the periodicities of 4.5 ± 0.6 angstrom and 3.7 ± 0.4 angstrom were detected. The domain sizes ranging from 70 angstrom to 250 angstrom, the transition temperatures from -15°C to 25°C and the maximum percentage of recrystallization from 13% to 34% increase as the number of polyether arms increases. The x-ray scattering peaks of the order phase grow up as I_1 + I_2 (1 - e~(-t/t(0))), where I_1 and I_2 are the initial intensity and the proportional intensity modulus, respectively. The relaxation time t0 of the order phase is varying as a power law with respect to the reduced temperature TR(=(T - T_c)/T_c): t0 = (35±10)·|TR|-1.42±0.07 seconds for the C_(60)-based star polymer containing 6 urethane-connected polyether; t0 = (315±64)·|TR|-1.68±0.08 seconds for the star model polymer containing 4 urethane-connected polyether arms.