The worldwide trend toward using cheap, atoxic and durable materials from renewable resources contributes to sustainable development. Thus, the investigation of the potential use of vegetal fibers as reinforcing agent in polymeric composites has gained new significance. Sisal fiber has emerged as a reinforcing material for polymers used in automobile, footwear and civil industries. In this work, properties such as hardness, tensile strength and tear strength of polymer composites composed by block copolymer styrene-butadiene-styrene (SBS) and 5, 10 and 20% by weight of sisal fiber were evaluated. The influence of conventional polymer processing techniques such as single-screw and double-screw extrusion, as well as the addition of coupling agent on the composite mechanical performance was investigated. Also, the morphology and thermal stability of the composites were analyzed. The addition of 2 wt. (%) maleic anhydride as coupling agent between sisal fiber and SBS has improved the composite mechanical performance and the processing in a double-screw extruder has favored the sisal fiber distribution in the SBS matrix.

Polyaniline (PAni), an electronic conductive polymer, has poor mechanical properties, such as low tensile, compressive and flexural strength that render PAni a non-ideal material to be processed for practical applications. Desired properties of polyaniline can be enhanced by mixing it with a polymer that has good mechanical properties. In this work, PAni was synthesised using functionalized sulfonic acids like camphorsulfonic acid (CSA) and dodecilbenzene sulfonic acid (DBSA) in order to promote PAni doping and improve its solubility, making possible conductive blends manufacture. The different forms of PAni were characterized by infra-red spectroscopy, thermal analysis, scanning electron microscopy and conductivity measurements. A conductive blend composed of PAni/DBSA and lower density polyethylene (LDPE) was obtained via solubilization method and its thermal, morphological and electrical properties were investigated. Concentrations as low as 5 wt. (%) of PAni was able to lead to electrical conductivities of PAni/LDPE blends in the range of 10-3 S.cm-1, showing great potential to be used in antistatic packing, electromagnetic shielding, anti-corrosion shielding or as a semiconductor.