Fig. 6 shows the storage modulus G0 and loss
modulus G00 of pure PBS and PBS/nano-CaCO3 composites
with various nano-CaCO3 loadings as a function of frequency
at 150 C. According to the linear viscoelastic theory,
it is generally believed that the G0 and G00 of polymer
based materials increase monotonously with an increase of
the frequency.