The complex dynamic viscosity (*) was measured using a
rheometer (Dynamic Analyzer RDA II, Rheometric Scientific Corp.,
USA). The samples were prepared as sheets by compression molding
to a disc of 1 mm thickness and 25 mm diameter, at 160 ◦C for
3 min. Measurements were carried out over the frequency range
0.1–1000 rad/s at a strain rate of 10% and a constant temperature
of 160 ◦C.