Biodegradable polylactide (PLA)/layered silicate nanocomposites have been prepared via solution route using two different kinds of organically modified nanoclays. The nanostructure as observed from wide-angle X-ray diffraction indicates intercalated hybrids and the extent of intercalation depends on the type of organic modifiers used. Melt-quenched PLA and its nanocomposites are predominantly amorphous but, after annealing, they are fairly crystalline. The nanohybrids show significant improvement in thermal properties as compared to neat polymer. The nature of interaction between nanoclays and matrix polymer depends on the organic modifiers used, as evident from varying heat of fusion and shifting of Fourier transform infrared peaks. The nanoclays act as nucleating agent, and thereby, control the spherulite dimension of the matrix. The comparison of biodegradation of PLA and its nanocomposites has been studied in enzyme, compost, and buffer solution. Biodegradability of PLA has significantly been enhanced in the presence of nanoclays and the rate varies on organic modifications. The surface morphology, before and after enzymatic degradation, confirms the relative rate of degradation through laser scanning confocal images, scanning electron microscope, and atomic force microscope.
Compacted polyaniline (PANI)/Layered silicate nanocomposites have been successfully prepared by simple in situ, core-shell, and ex situ polymerization routes using AnHCl as a predecessor through chemical oxidation method. The structure, chemical groups, electronic transition and properties were investigated by XRD, SEM, HRTEM, UV Visible, DC electrical conductivity, TGA, and DSC. The XRD results reveals that HCl-treated Cloisite 20A, and PANI-ES/Cloisite 20A nanocomposites are delaminated. Flake-like morphologies were observed in Cloisite 20A and HCl-treated Cloisite 20A, whereas different rate of compacted fibrous morphologies of prepared PANI-ES/Cloisite 20A nanocomposites were observed as evident from SEM images. The Si-O FTIR band position does not change even after HCl treatment of Cloisite 20A, but different FTIR peaks positions of PANI-ES/Cloisite 20A nanocomposites were shifted from pure PANI-ES peaks after using Cloisite 20A nanoclays. UV-Visible spectra indicated the increment of charge carrier within the PANI-ES/Cloisite 20A nanocomposites compared to the pure one. The prepared nanohybrids showed significantly improved thermal property compared to pristine PANI-ES as clear from TGA and DSC analysis. The highest DC electronic conductivity of nanocomposite prepared by core-shell route is found to be 5.12 S/cm using linear four probe techniques. In addition, the charge transport mechanism was understood with and without loading Cloisite 20A in PANI-ES. The conductivity data supported the temperature-dependence relationship σ(T) = σ0.exp[-To/T)1/4] and followed characteristic of three-dimensional variable-range hopping (3D‒VRH) mechanism. In addition, we were discussed the response of Nitrogen dioxide (NO2) gas with polyaniline based sensor materials.
N-substituted PANI-ES was obtained from N-phenyl-β-alanine (N-substituted aniline). N-phenyl-β-alanine was synthesized chemically from methyl acrylate and aniline precursor. ESI-MS, H1NMR spectroscopy and FTIR spectroscopy are employed to characterise the N-phenyl-β-alanine for structure elucidation. The structure and properties of corresponding polymers were investigated by X-ray diffraction, FTIR, UV-Visible, H1NMR, FESEM, solubility, and DC conductivity. On the basis of experimental results of prepared N-substituted aniline monomer and its corresponding polymer is proposed. At room temperature, the average DC conductivity of as-prepared PANI polymers was found in semiconducting range, which is 0.153 S/cm for poly (3-methyl (phenyl amino) propionic acid. We also were analysed temperature dependent DC conductivity with and without magnetic field of as prepared PANI polymers to understand the conduction mechanism and it was followed variable-range hopping (VRH) process. In addition, we were discussed the response of liquefied petroleum gas (LPG) with polyaniline based sensor materials.
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