Preparação e caracterização de blendas eletricamente condutoras de silicona e polianilina

Abstract

Polyaniline (PAni) is a conducting polymer that has potential application in obtaining new technology electrical and electronic devices. However, its application is limited because it is a difficult material processability. One of the ways used to circumvent this problem is the inclusion of functionalised organic acids in their structure, such as dodecylbenzenesulfonic acid (DBSA). The acid acts as both dopant as compatibilizing improving the solubility of polyaniline in nonpolar organic solvents and other polymer matrices to form blends. Obtaining blends with an elastomeric polymer having excellent property such as silicone, can generate a new material with further electrical and mechanical properties, is often not usual that can be used in applications involving piezoelectric or piezoresistive behavior. Thus, this study aimed to obtain silicone blends with PAni(DBSA) by co-dispersion of the components in a suitable solvent, and formation of blankets evaporation of the solvent in the proportions by weight silicone / PAni (DBSA) of 95/05 90/10 85/15 80/20 and 75/25, characterization of the blends by infrared spectroscopy, thermogravimetry, scanning electron microscopy, measurement of volume and surface resistivity, mechanical tests. The results presented in this work showed that temperature had significant influence in the formation of the blends. The PAni(DBSA) had yields above 84%. Through the characteristic peaks in the absorption curve of PAni (DBSA) in the infrared region formation was noted on the conductive form of polyaniline salt esmeradina. The blends were generally stable to the temperature 120 ° C. In electrical conductivity measurements by the method of the four points obtained blends rightly Silicone/PAni(DBSA) 75/25 showed electrical conductivity 10 orders of magnitude greater than the value of pure silicone. By measuring the volumetric resistivity was observed that for a content of 20% by volume resistivity of PAni (DBSA) was reduced by 10 orders of magnitude compared to silicone. By scanning electron microscopy indicated a heterogeneous distribution of particles of PAni(DBSA), which made the surface electric resistivity have different values for upper and lower surface of the blends. For the tensile test showed that by increasing the PAni(DBSA) in the silicone matrix the blends were more rigid and had lower strength and elongation at break.