The effect of BTPC concentration on the complex viscosity and the shear viscosity of PVDF/BTPC blends at low frequencies (0.
Thus, the flow activation energy is not significantly affected by addition of BTPC.
The values of the coefficients of expansion obtained are similar in magnitude to previously reported values for different polymer melts [6, 26, 27], The coefficient of thermal expansion is not significantly affected by addition of BTPC.
BTPC is an off-white powder which was found to dissolve in molten PVDF.
The FTIR spectra for the PVDF films prepared with the different weight fractions of BTPC are shown in Figure 11.
X-ray diffraction peaks for the films prepared with pure PVDF and with 1 and 3 wt % BTPC are shown in the Figure 12.
The maximum intensity in a lobe occurs at different scattering angles for the different BTPC concentrations.
The variation of dielectric constant with frequency for PVDF films with different BTPC concentrations is shown in Figure 14.
The dielectric loss at high frequencies is independent of BTPC concentration, but at low frequencies the dielectric loss increases with increase in BTPC concentration.
Addition of BTPC results in an increase in the conductivity at low frequencies, with a nearly constant value below a critical frequency.
Data at different temperatures were found to superimpose to a single master curve, for each BTPC concentration, using time-temperature superposition.
Addition of BTPC resulted in a significant increase (35%) in the plateau viscosity as well as a yield stress regime at very low frequencies in which the complex viscosity increases with decreasing shear rate.