Effect of oxidants and anionic surfactants on the morphology and permittivity of polypyrrole and its blends with epoxy resin

Abstract

SbstractIn this work, conductive polymers were prepared based on polypyrrole (PPy) and its blends with epoxy resin. The chemical syntheses of PPy used two oxidants (Fe 2 (SO 4 ) 3 and FeCl 3 .6H 2 O) and two surfactants (DBSNa and DBSA). PPy samples and their blends were characterized by scanning electron microscopy, electrical conductivity by four points, and measurements of complex parameters of electric permittivity (ε) and magnetic permeability, in the frequency range of 8.2 to 12.4 GHz. The micrographs of the fractured surfaces show that the PPy synthetized in the presence of surfactants has particles with smaller diameters, and the oxidant sulfate favored the formation of elongated structures, called fillets. The analysis of the blends found a homogeneous distribution of PPy clusters in epoxy resin matrix, which did not favor the electrical conductivity of these materials. On the other hand, the measurements of the complex parameters of the permittivity show that the blends have increasing values when the PPy concentration is increased in the epoxy resin.

Electrostatic or Steric Stabilization of the Cellulose Nanostructures Using Different Modifying Agents

“…The peaks between 1300 and 1400 cm −1 are associated with highly mixed vibrations (νC═O, δCC 10 C, δCC═O, ν[C─O]), and small shifts are indicative of changes/disturbances in the vibrational behavior of the carbonic structure. [ 21,22 ]…”

“…[ 3 ] The GA (polyethylene glycol) has characteristics peaks between 1500 and 850 cm −1 , related to C─O, and C─H vibrations; these peaks are in the same region of cellulose characteristics peaks. [ 21 ] After GA adsorption, the intensity of the peaks 1034, 947, and 841 cm −1 slight changed, which is associated with the C─O bonding of GA and cellulose interaction, C─H stretching of β‐glycosidic bonds of cellulose, and out‐of‐plane bending vibrations of ‐OH of the crystalline region in the PEG. [ 18,24 ] The NS and GA modifiers showed similar spectral characteristics due to the high structural similarity of these materials; in these modified‐CNS samples, changes to CH 2 rocking and C─O─C stretching frequencies are common and suggest strong interactions between CNS and modifier agents.…”