The Use of Le Bail Method to Analyze the Semicrystalline Pattern of a Nanocomposite Based on Polyaniline Emeraldine-Salt Form andα-Al₂O₃

Abstract

Ceramic nanocomposites constituted by a matrix ofα-Al2O3microparticles reinforced by polyaniline emeraldine-salt form (PANI-ES) nanoparticles were prepared byin situpolymerization and characterized structural and morphologically. Peaks related to both materials were observed through XRD technique: PANI-ES presented peaks at2θ= 8.9, 14.9, 20.8, 25.3, 27.1, and 30.0° and inα-Al2O3phase peaks were found at2θ= 25.6, 35.2, 37.9, 43.5, 52.6, 57.6, and 68.1°. Nanocomposite crystallinity percentage was estimated around 70%. SEM showed a polymerization of PANI-ES over alumina plates. By Le Bail method it was observed that PANI-ES andα-Al2O3have crystallite average size around, respectively, 41 and 250 Å. By FTIR analysis characteristic absorption bands of both materials were identified. Additional bands indicating new chemical bonds were not observed, suggesting that nanocomposite was formed by physical deposition. Nanocomposite DC electrical conductivity was found around 0.24 S/cm (against1.84×10-4 S/cm for pure PANI-ES), showing an increase of about 1,300 times compared to the pure PANI-ES at room temperature. Thus, this paper showed that both materials have kept its original structural characteristics and exhibited high electrical conductivity when combined in nanocomposite form.

Nanocomposite based on polyaniline emeraldine-base and α-Al2O3: A structural characterization

“…Additional bands indicating new chemical bonds to form the nanocomposite weren ot observed, suggesting physical deposition of PANIonthe alumina plates. No chemical interaction was observed by Sanches et al [17] either in ananocomposite constituted of polyaniline emeraldine-salt form and a -Al 2 O 3 .…”

“…Dark bluen anocomposite madef rom polyaniline emeraldine-base and aluminum oxide (PANI-EB/a -Al 2 O 3 )w as synthesized based on previous works of Zhang [5] and Sanches et al [17,25] withs ome modifications. Aniline monomer was purchased from Aldrich and further distilled.…”

“…Figure 3s hows the decomposition of the XRD pattern for crystallinity estimation. Sanches et al [17] estimated the percentage of crystallinity to be around 70 %for ananocomposite composed of polyaniline emeraldine-salt (PANI-ES) and a -Al 2 O 3 .T he crystallinity of pure PANI-EB is estimated to be ca. 30 % [39].…”

“…The DC electricalconductivity for nanocomposite using polyaniline and ac eramic matrix also showsd ifferent values in literature depending on theirmethods of synthesis and the oxidation state of polyaniline. Nanocomposite formed by PANI-ES and aluminashowed DC electrical conductivity around 0.24 Scm -1 (against 1.84 · 10 -4 Scm -1 for pure PANI-ES), presentinganincrease of about 1300 times when compared withthe pure PANI-ES at room temperature [17]. Su and Kuramoto [47] synthesized aprocessable PANI-EB/titanium dioxide nanocomposite with suitable conductivity (1 -10Scm -1 )t hat increaseda fter thermal treatment at 80 8 Cfor 1h.However, Teoh et al [18] obtained adecrease in DC electrical conductivity when they synthesized composite with nanofiber morphology by oxidative polymerization of aniline with alumina nanofibers.…”

Effect of Flame Spray Deposition Parameters on The Microstructure of Al2 O3 - 13 %TiO2 Coatings Applied Onto 7075 Aluminum Alloy

“…Typical phases found in AT-coatings include α-Al 2 O 3 , γ-Al 2 O 3 , TiO 2 and Al 2 TiO 5 8 . Aluminum titanate (Al 2 TiO 5 ) is desirable for applications involving high temperature due to its low thermal expansion coefficient (1.5x10 -6 K -1 ), low thermal conductivity (0.9-1.5 Wm -1 K -1 ), low Young's modulus (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and high melting point (1860 ± 10ºC) 9,10 . Additionally, Al 2 TiO 5 has been used by the industry because it has high thermal shock and corrosion resistances (10) .…”