Extruded polyaniline/EVA blends: Enhancing electrical conductivity using gallate compatibilizers

• Gallate compatibilizers raised PANI–EVA conductivity up to values similar to PANI's.
• Polymerized PANI–DBSA with conductivity 2 S cm−1 was characterized by XPS and FTIR.
• The low processing temperature of EVA prevented conductivity losses at blending PANI.
• Enhanced conductivity and compatibilizer role were studied by rheology, FTIR and SEM.
• Improved PANI dispersion and interactions of compatibilizer and PANI–EVA were shown.

The role played by alkyl gallate compatibilizers to enhance the conductivity of extruded polyaniline (PANI)–polyethylene-co-vinyl-acetate (EVA) composites was investigated. PANI doped with dodecylbenzensulfonic acid (DBSA) with 2 S cm−1 conductivity was synthetized via emulsion pathway. The achievement of doped emeraldine salt was confirmed by infrared and X-ray photoelectron spectroscopy.Two gallic acid compatibilizers, namely octyl gallate (OG) and lauryl gallate (LG) were studied by adding increasing amounts (0–20%) to the composite. Gallate compatibilizers enhanced the conductivity of the blend by one order of magnitude, achieving values similar to the pure polyaniline (1–2 S cm−1) using only 30% of PANI. Infrared spectral changes proved the formation of intermolecular hydrogen bonds between EVA and gallate esters and suggested additional interactions with PANI. These interactions improved the adhesion between PANI and EVA, thus explaining the better dispersion of the PANI observed by SEM and the increase in rheological viscosity and shear rate measurements.

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