Preparation and characterization of conductive HDPE/LLDPE/Polyaniline blends

Abstract

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.

Effect of conductive polyaniline in thermoplastic natural rubber blends on the mechanical, thermal stability, and electrical conductivity properties

“…When the content of PANI exceeded the optimum level (i.e., 4–5 wt % PANI), it can be observed for negative trend (decreased by 21.1–9.6% for tensile strength and 13.2–9.2% for elongation at break), as shown in Figure . This can be attributed to the agglomeration of PANI which resulting in the fragility of the sample . The formation of agglomerates can be correlated to the material's polarity in which Passador et al .…”

“…From the conductivity perspective, the conductivity properties of a polymer are theoretically affected by the increment of conductive channel numbers with the increasing conductive polymer content . Oliveira et al . who prepared the HDPE/linear LDPE (LLDPE)/PANI conductive blend via melt compounding has reported that the electrical conductivity increased and achieved to a power scale of 10 −6 when the 40 wt % PANI was added as compared to 0, 5, 10, 15, and 20 wt % PANI (showing insignificant improvement of electrical conductivity ~10 −11 S cm −1 ).…”

“…In the aspect of mechanical properties, the increase of PANI content resulted in the negative trends typically for elongation at break due to the poor intrinsic mechanical properties of PANI where its inflexibility is imparted by the aromatic rings and double bonds in its structure, as reported by Cote et al 14 From the conductivity perspective, the conductivity properties of a polymer are theoretically affected by the increment of conductive channel numbers with the increasing conductive polymer content. 17 Oliveira et al 18 who prepared the HDPE/linear LDPE (LLDPE)/PANI conductive blend via melt compounding has reported that the electrical conductivity increased and achieved to a power scale of 10 −6 when the 40 wt % PANI was added as compared to 0, 5, 10, 15, and 20 wt % PANI (showing insignificant improvement of electrical conductivity ~10 −11 S cm −1 ). There are other factors that affect the conductivity properties, for instance, the inclusion of nanofillers or nanoparticles would lead to good dispersion of filler in the matrix and thus improving the conductivity of composite materials.…”

The Effect of Sonication Time on the Properties of Electrically Conductive PANI/Sago Starch Blend Prepared by the One-Pot Synthesis Method

“…It gives a straight line fit, which implies that the samples undergo direct transition. Then, the band gap has been extracted by extrapolating the straight portion of the graph on the hυ axis at α = 0 (Oliveira et al, 2016). The energy band gap results obtained from Tauc's plot correlated with electrical conductivity values, as the size of the energy band gap determines whether the polymer is a metal, semiconductor, or insulator.…”

“…loss up until ∼150 • C due to the evaporation of moisture and volatile impurities; stage 2 involves weight loss between 150 and 350 • C due to the loss of dopant acid (Neelgund and Oki, 2011); and stage 3 involves weight loss between 400 and 800 • C due to the exothermic thermal decomposition of PANI with different degrees of polymerization (Sai et al, 2006). In the case of Sago starch, the weight loss of Sago begins at 290 • C with a sharp weight loss from 84 to 18% at 370 • C. Compared to neat PANI and native Sago, PANI/Sago showed initial weight loss at a much lower temperature of 200 • C. This could be because, at such higher temperatures, the molecular interaction (e.g., hydrogen bonding) between protonic acid, PANI, and Sago is not effective; therefore, a major weight loss takes place (Larimi et al, 2012;Lukasiewicz et al, 2014;Oliveira et al, 2016). The final degradation temperatures for all the blends were higher than those of the Sago starch.…”