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Abstract. The electrical properties of conducting polymer and insulating polymer matrix combined with attractive mechanical properties and processing advantages of the polymers has now attained a level of maturity consistent with a new set of opportunities to develop a wide range of application based conducting polymer composites. Polyaniline has been widely investigated due to its low cost, easy synthesis and high electrical conductivity. The purpose of this work was to prepare high density polyethylene (HDPE)/linear low density polyethylene (LLDPE)/ polyaniline (PANI) blends with 5, 10, 15, 20 and 40 wt% of polyaniline by melt compounding in a torque rheometer. The final blends were prepared with a blend ratio of 1:1 HDPE/LLDPE. The PANI was synthesized by a following a well-established method for the synthesis of the emeraldine base form using HCl as dopant. The HDPE/LLDPE/PANI blends were analyzed by FTIR, mechanical, thermal and electrical properties. Usually, polymer blends with PANI were prepared by solution or compression of powders. In this work the composites were successfully prepared by melt compounding and it was observed an increase in the equilibrium torque with addition of polyaniline and there was no degradation of the polymer matrix or PANI. FT-IR spectrum analysis was performed to identify the bonding environment of the synthesized material and was observed that simply physically mixture occurred between PANI and HDPE/LLDPE blend. Tensile tests showed reduction of Young´s modulus only for the blend with 40 wt% of PANI, however a decrease in elongation at break was observed. On the other hand, the addition of polyaniline increased the electrical conductivity. The HDPE/LLDPE blend showed a conductivity of 6.5x10 -11 S/cm and the addition of 40wt% of PANI increased the electrical conductivity for 3.7x10 -6 S/cm.

In this work, polyaniline (PANI) in emeraldine-base form, synthesized by chemical oxidation polymerization, was protonated with hydrochloric acid (HCl). Composites based on high-density polyethylene (HDPE) and linear-low density polyethylene (LLDPE) blends with PANI were prepared in molten condition using a torque rheometer. The effect of compatibilizer agent (maleic anhydridegrafted high density polyethylene, HDPE-g-MA) and different contents of PANI on the blends-based composites was also investigated. Thermal, mechanical, and electromagnetic (electric permittivity) measurements and morphological aspects of the composites were evaluated. The addition of PANI content in the composites decreases the degree of crystallinity of HDPE and LLDPE blends, which implies that PANI particles make it difficult for co-crystallization to occur in the HDPE and LLDPE, respectively. On the other hand, the addition of compatibilizer agent in the HDPE and LLDPE blends increased the degree of crystallinity. The complex parameters of permittivity in the frequency range of 8.2 to 12.4 GHz varied as a function of the PANI content in the blend. It was also observed that the compatibilizer agent increased the composite stiffness and decreased the electric permittivity values. This result shows that the increasing rigidity of the molecular structure of the polyethylene matrix hindered the dissipation of the electromagnetic energy in the sample.