Polypyrrole nanoparticles coated amorphous short silica fibers: Synthesis and characterization

Electrically conductive composites of polyurethane derived from castor oil with polypyrrole‐coated peach palm fibers

“…It is interesting to note that the percolation threshold of PU/PPF-PPy is lower than that of PU/PPy composites, probably due to the high aspect ratio of PPy-coated PPF fibers dispersed in the PU matrix. This result corroborates those reported in the literature, in which a lower percolation threshold was also observed for polymer systems containing disperse phase of polyaniline-coated coconut fibers [7], PPy-coated amorphous silica fibers [5] and PPy-coated polyamide 66 or PP fibers [9] when compared to the same insulating polymer matrix with spherical particles of the conducting phase.…”

“…The value of the critical exponent for PU/PPy composites was quite similar to that reported for SEBS/PPy systems [5]. According to Grimaldi, et al [34], this behavior could be attributed to a tunneling mechanism.…”

The effect of compressive stress on the electrically resistivity of poly(vinylidene fluoride)/polypyrrole blends

“…in which c is a constant, t a critical exponent, the resistivity, f the fraction of the conductive medium and f p the fraction at the percolation threshold, expressed as a weight fraction [9,20,27]. From the fitting of the experimental data, f p and t values of 4 wt% and 1.1, respectively, have been found.…”

“…2 shows the FTIR spectra of PPy, PVDF and PVDF/PPy blends prepared by solution casting method. The absorption bands at 1520 cm −1 and 1424 cm −1 in the PPy spectrum can be assigned to the C C and C N stretching vibration of pyrrole ring, respectively [27,28]. The absorption band at 1275 cm −1 is assigned to C H or C N in-plane deformation modes [29], while that those at 1121 and 1015 cm −1 are assigned to the C H bending modes.…”

“…The absorption band at 1076 cm −1 corresponds to the mode in-plane deformation vibration of N + H 2 for doped PPy. The band centered at 965 cm −1 is related to the C H out-of-plane deformation of pyrrole ring [27,28]. PVDF film spectrum showed absorption bands at 1402 and 876 cm −1 (band for amorphous phase) attributed to the C F stretching vibration and at 1172 cm −1 assigned to the C C bond [30][31][32].…”