Semiconducting elastomers based on polyaniline/clay nanocomposites and SEBS obtained by an alternative processing technique

• Published in: Synthetic metals 2020-10, Vol.268, p.116460, Article 116460
• Main Authors: De León-Almazán, Claudia María, Estrada-Moreno, Iván Alziri, Olmedo-Martínez, Jorge L., Rivera-Armenta, José Luis
• Format: Article
• Language: English
• Subjects: Butadiene; Clay; Conducting polymers; Dynamic mechanical analysis; Elasticity; Elastomer; Elastomers; Electrical properties; Electrical resistivity; Electrochemical impedance spectroscopy; Fillers; Homogeneity; Insulation; Low temperature; Nanocomposites; Polyaniline; Polyanilines; Raman spectroscopy; Rubber; Semiconductor; Spectrum analysis; Stiffness
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2020.116460

•The preparation of a semiconducting elastomer by an alternative path was carried out.•The traditional processing method leads to a highly insulating material, while the proposed method results in electrically semiconducting materials.•Electrical conductivity and the capacitive behavior indicate that resulting material could be useful for energy storage devices.•Mechanical behavior of obtained composites was similar to those obtained by typical method. The use of Polyaniline (PAni) as conductive filler in several kinds of non-conductive polymers, such as elastomers, has been extensively studied in the production of easily processable semiconductors. This work focuses on the use of a PAni/clay nanocomposite (PCN) – instead of pristine PAni – as conductive filler of styrene-butadiene rubber (SEBS) to produce a PCN/SEBS semiconducting elastomer. In order to accomplish this, a novel solvent-free and low-temperature press-processing technique was proposed and applied. It was also compared to the traditional rubber mechanical processing method. The preparation of PCN/SEBS was conducted by following a two-stage procedure: Pain in situ synthesis and mechanical mixing. PCN/SEBS was characterized by Raman spectroscopy, dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM), the electrical properties were measured by means of the two-probe technique and electrochemical impedance spectroscopy (EIS). It was found that the traditional processing method led to a highly insulating material, while the proposed procedure results in semiconducting composites, showing electrical conductivity values up to 10−7 S cm−1. From the mechanical standpoint, this novel treatment results in composites with lower stiffness at low temperatures and similar elastic behavior at the transition region when compared to the material produced by the typical mixing chamber procedure. Although this method still needs to be improved since these materials show less homogeneity than their counterparts and they crumble at ∼100 °C, this work sets the foundation for an alternative processing method to obtain PAni-based semiconducting elastomers.