Conductive composites of polyamide-6 with polyaniline coated vegetal fiber

Vegetal fibers, like curaua fibers, are used as reinforcement for thermoplastics in biocomposites, due to their low density and availability. Polyaniline can be deposited on the surface of fibers producing electrically conductive fibers. The conductivity of these PAni treated fibers suggest their use as antistatic agents. Composites of polyamide-6 with Pani-treated curaua fibers were prepared in a twin-screw extruder and specimens were obtained by transfer-molding. The electrical properties of the modified fibers and composites were measured and the mechanical properties were evaluated by tensile tests. The morphology of the composites, the fibrillation process and adhesion at the polymer/fiber interface were observed by scanning electron micrography. The ATR-FTIR showed that the most important bands of PAni were present in the modified fibers. The thermogravimetric results showed that the PAni-coated fibers present two distinct weight loss processes with a positive shift of the PAni degradation process, corresponding to a stabilization effect. The composite has a conductivity of 5 x 10(-7) S cm(-1), three orders of magnitude higher than pure polyamide-6, and in the range of antistatic materials. The composites with PAni-coated fibers show better mechanical performance than the polymer matrix, and SEM shows good adhesion at the polymer/fiber interface. (C) 2011 Elsevier B.V. All rights reserved.