Compósito formado por poli(o-etoxianilina) e zinco metálico: uma abordagem estrutural, espectroscópica e morfológica

Abstract

The present study aimed to carry out the synthesis and characterization of a polymeric matrix composite formed by the Intrinsically Conducting Polymer poly(o-ethoxyaniline) (POEA) and by metallic zinc (Zn; 0.5 g and 1.5 g) using 1M HNO3 as doping acid, as a way to verify the interactions that occur between the conducting polymer and the metal, since in recent studies it was possible to observe that the incorporation of metals into the syntheses of polymeric composites, resulted in an active behavior of the polymer, depositing itself as a reinforcement. The structural characterization of the materials was performed using X-Ray Diffraction (XRD) techniques, crystallinity percentage estimative, Structural Refinement by the Le Bail Method, Fourier-transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The most defined diffraction peaks of pure POEA were present at angular positions below 2θ = 30°, and the pronounced peak width suggests nanometric crystallites. The XRD patterns of the composites mostly exhibited the diffraction peaks characteristic of POEA, showing that the addition of the metal did not alter the crystalline structure of the polymer. However, in the composite POEA + 1.5g of Zn, more evident diffraction peaks of the metallic phase were observed, in addition to a slight increase in interplanar spacing, indicating possible stress in the Zn crystalline network. The crystallinity percentage of POEA was estimated by the peak deconvolution method at around 58 (± 2)%. When comparing the cell parameters of PANI and POEA, it was possible to observe an increase in a (from 5.7328 for PANI to 7.6352 for POEA) and in b (from 8.8866 for PANI to 12.4220 for POEA) due to the presence of the POEA side group. POEA crystallites presented a prolate shape. The FTIR spectra showed that, chemically, POEA was not sensitive to the presence of metallic Zn in the form of composites, suggesting the physical interaction between the phases. The doping of POEA using HNO3 played a fundamental role in the formation of multimorphologies, with the presence of vesicles, nanorods, nanofibers and granules being observed in both pure POEA and composites. The presence of the metal did not change the morphology of the POEA in the form of a composite, corroborating the suggestion of physical interaction between the phases.