Synergic effect in electrical conductivity using a combination of two fillers in PVDF hybrids composites

• Published in: European polymer journal Vol. 49; no. 10; pp. 3318 - 3327
• Main Authors: da Silva, Aline Bruna, Marini, Juliano, Gelves, Genaro, Sundararaj, Uttandaraman, Gregório, Rinaldo, Bretas, Rosario E.S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-10-2013; Elsevier
• Subjects: Applied sciences; Composites; Electrical conductive composites; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; PVDF/MWCNT nanocomposites; PVDF/PPy blends; PVDF/PPy/MWCNT hybrid composites; Technology of polymers; PVDF/PPy blends; Electrical conductive composites; PVDF/MWCNT nanocomposites; PVDF/PPy/MWCNT hybrid composites; Electrical conductivity; Polymer blends; Electrical properties; Dispersion degree; Carbon nanotubes; Experimental study; Conducting polymers; Multiwalled nanotube; Morphology; Vinylidene fluoride polymer; Concentration effect; Percolation; Nanocomposite; Pyrrole polymer
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/j.eurpolymj.2013.06.039

•Novel binary PVDF/PPy conductive blends, PVDF/MWCNT conductive nanocomposites.•Novel hybrid PVDF/PPy/MWCNT conductive nanocomposites.•Electrical conductivities of the hybrid were always much higher.•Addition of two conductive fillers had a synergistic effect on the conductivity.
The objective of this work was to prepare novel conductive blends of poly(vinylidene fluoride) (PVDF) with polypyrrole (PPy) and to compare their performance with PVDF/multiwall carbon nanotube (MWCNT) composites and novel PVDF/PPy/MWCNT hybrid systems. All the compositions were prepared by melt mixing using a miniature mixer. The mixtures were characterized by Fourier transformed infrared (FTIR), wide angle X-ray diffraction (WAXD), thermogravimetric analyses (TGA), scanning and transmission electron microscopy (SEM and TEM, respectively) and volume electrical resistivity. For the binary PVDF/PPy and PVDF/MWCNT systems, percolation thresholds of 10 and 0.3wt%, respectively, were found. In the hybrid systems, however, the percolation threshold for each filler was lower than in the binary systems, but the electrical conductivities were always much higher at all concentrations than the conductivities of the binary systems. Therefore, the addition of both fillers had a synergistic effect on the hybrid system conductivity, which was attributed to its morphology: the PPy increased the homogeneity of the MWCNT distribution and decreased the available free volume for the MWCNT; as a result the MWCNT rolled around the PPy particles bridging them through the PVDF matrix, increasing the quantum tunneling effect and thus, the electrical conductivity of the system.