Abstract:Poly(o-methoxyaniline) (POMA) was synthesized by oxidative polymerization of the monomer o-methoxyaniline. POMA/ poly(methyl methacrylate) (PMMA) blends were produced by dissolving both polymers in chloroform (CHCl 3 ).The amount of camphor sulfonic acid (CSA) used as dopant of POMA was different, providing two methods for preparation of the blends. Solutions were analyzed by Fourier transform infrared spectroscopy (FTIR) and then deposited on glass substrate by spin coating for characterization by atomic forc… Show more
“…The band at 3437 cm −1 is attributed to the formation of NH bonds due to the protonation of nitrogen, in accordance with the literature [16]. The contribution at 2800 cm −1 may be associated with both axial deformation of C-H from aromatic carbon and also C-H stretching of the OCH 3 group in the polymeric chain [26]. The band at 1579 cm −1 is associated with quinoid (Q) structure and 1490 cm −1 band with benzenoid (B) structure.…”
Section: Computer Simulationsupporting
confidence: 89%
“…The presence of bands at 1500 cm −1 and 1600 cm −1 is also observed. According to the literature these contributions are related to the polymer formation from amine and imine units [26]. Table 3 summarizes the main infrared bands shown in Figure 2.…”
This study involves the preparation of conducting composites based on poly(o-methoxyaniline) (POMA) and carbon nanotubes (CNT) and the evaluation of them as radar absorbing materials (RAM), in the frequency range of 8.2–12.4 GHz (X-band). The composites were obtained by synthesis in situ of POMA in the presence of CNT (0.1 and 0.5 wt% in relation to the o-methoxyaniline monomer). The resulting samples—POMA/CNT-0.1 wt% and POMA/CNT-0.5 wt%—were incorporated in an epoxy resin matrix in the proportion of 1 and 10 wt%. FT-IR analyses show that the POMA was successfully synthesized on the CNT surface. SEM analyses show that the synthesized POMA recovered all CNT surface. Electrical conductivity measurements show that the CNT contributed to increase the conductivity of POMA/CNT composites (1.5–6.7 S·cm−1) in relation to the neat POMA (5.4 × 10−1 S·cm−1). The electromagnetic characterization involved the measurements of complex parameters of electrical permittivity (ε) and magnetic permeability (µ), using a waveguide in the X-band. From these experimental data reflection loss (RL) simulations were performed for specimens with different thicknesses. The complex parameters show that the CNT in the composites increased ε and µ. These results are attributed to the CNT network formation into the composites. Simulated RL curves of neat POMA and POMA/CNT in epoxy resin show the preponderant influence of POMA on all RL curves. This behavior is attributed to the efficient CNT recovering by POMA. RL results show that the composite based on 10 wt% of POMA/CNT-0.5 wt% in epoxy resin (9 mm thickness) presents the best RL results (≈87% of attenuation at 12.4 GHz).
“…The band at 3437 cm −1 is attributed to the formation of NH bonds due to the protonation of nitrogen, in accordance with the literature [16]. The contribution at 2800 cm −1 may be associated with both axial deformation of C-H from aromatic carbon and also C-H stretching of the OCH 3 group in the polymeric chain [26]. The band at 1579 cm −1 is associated with quinoid (Q) structure and 1490 cm −1 band with benzenoid (B) structure.…”
Section: Computer Simulationsupporting
confidence: 89%
“…The presence of bands at 1500 cm −1 and 1600 cm −1 is also observed. According to the literature these contributions are related to the polymer formation from amine and imine units [26]. Table 3 summarizes the main infrared bands shown in Figure 2.…”
This study involves the preparation of conducting composites based on poly(o-methoxyaniline) (POMA) and carbon nanotubes (CNT) and the evaluation of them as radar absorbing materials (RAM), in the frequency range of 8.2–12.4 GHz (X-band). The composites were obtained by synthesis in situ of POMA in the presence of CNT (0.1 and 0.5 wt% in relation to the o-methoxyaniline monomer). The resulting samples—POMA/CNT-0.1 wt% and POMA/CNT-0.5 wt%—were incorporated in an epoxy resin matrix in the proportion of 1 and 10 wt%. FT-IR analyses show that the POMA was successfully synthesized on the CNT surface. SEM analyses show that the synthesized POMA recovered all CNT surface. Electrical conductivity measurements show that the CNT contributed to increase the conductivity of POMA/CNT composites (1.5–6.7 S·cm−1) in relation to the neat POMA (5.4 × 10−1 S·cm−1). The electromagnetic characterization involved the measurements of complex parameters of electrical permittivity (ε) and magnetic permeability (µ), using a waveguide in the X-band. From these experimental data reflection loss (RL) simulations were performed for specimens with different thicknesses. The complex parameters show that the CNT in the composites increased ε and µ. These results are attributed to the CNT network formation into the composites. Simulated RL curves of neat POMA and POMA/CNT in epoxy resin show the preponderant influence of POMA on all RL curves. This behavior is attributed to the efficient CNT recovering by POMA. RL results show that the composite based on 10 wt% of POMA/CNT-0.5 wt% in epoxy resin (9 mm thickness) presents the best RL results (≈87% of attenuation at 12.4 GHz).
“…And the stretching nitrile (CN) group shifted to higher energy position at 2360 cm −1 (CN), ascribing to the interaction of amide nitrogen (DMF) and nitrile group (PAN) . The spectra of raw PMMA powder, PMMA fibers, PMMA/PAN porous thin films, core–shell hollow PMMA/PAN fibers, and PMMA/PAN porous fibers showed a weak peak around 999 cm −1 and two strong peaks at 1146 and 1726 cm −1 , corresponding to the vibrations of C–H, axial asymmetric bend of CCO and PMMA ester (CO) groups, respectively (Figure a–e) . The peaks at around 1195–1265 cm −1 were obtained due to the COC stretching and deformation vibration .…”
Section: Resultsmentioning
confidence: 96%
“…[50][51][52][53][54] The spectra of raw PMMA powder, PMMA fibers, PMMA/PAN porous thin films, core-shell hollow PMMA/PAN fibers, and PMMA/PAN porous fibers showed a weak peak around 999 cm −1 and two strong peaks at 1146 and 1726 cm −1 , corresponding to the vibrations of C-H, axial asymmetric bend of C C O and PMMA ester ( C O) groups, respectively (Figure 4a-e). [55] The peaks at around 1195-1265 cm −1 were obtained due to the C O C stretching and deformation vibration. [55,56] The spectra of the PMMA powders, PMMA fibers, PMMA/PAN porous thin films, core-shell hollow PMMA/PAN fibers, and PMMA/PAN porous fibers showed the obvious peaks at around 2950 and 3002 cm −1 , attributing to the C H bonds stretching vibrations of the CH 2 and CH 3 groups in PMMA (Figure 4c-e).…”
Section: Morphology Studymentioning
confidence: 99%
“…[55] The peaks at around 1195-1265 cm −1 were obtained due to the C O C stretching and deformation vibration. [55,56] The spectra of the PMMA powders, PMMA fibers, PMMA/PAN porous thin films, core-shell hollow PMMA/PAN fibers, and PMMA/PAN porous fibers showed the obvious peaks at around 2950 and 3002 cm −1 , attributing to the C H bonds stretching vibrations of the CH 2 and CH 3 groups in PMMA (Figure 4c-e). [57,58] And the peak at 1450 cm −1 , at the same position with PAN, was assigned to the C H vibration of PMMA.…”
The polyacrylonitrile/polymethyl-methacrylate (PMMA/PAN) porous fibers, core–shell hollow fibers, and porous thin films are prepared by coaxial electrospinning, single electrospinning, and spin-coating technologies, respectively. The different morphologies arising from different processes display great influences on their thermal and crystalline properties. The adding of PMMA causes porous structure due to the microphase-separation structure of immiscible PMMA and PAN phases. The lower weight loss, higher degradation temperature, and glass-transition temperatures of porous thin films than those of porous fibers and core–shell hollow fibers are obtained, evidencing that the polymer morphologies produced from the different process can efficiently influence their physical properties. The orthorhombic structure of PAN crystals are found in the PMMA/PAN porous thin films, but the rotational disorder PAN crystals due to intermolecular packing are observed in the PMMA/PAN porous fibers and core–shell hollow fibers, indicating that different processes cause different types of PAN crystals.
In this study, thin films of polymer poly(methyl methacrylate) were prepared using a drop casting method. Two newly synthesized aldehyde derivatives, 2‐bromomalonaldehyde and 5,6‐dihydroimidazo[2,1‐b]thiazole‐2‐carbaldehyde, were used at different concentrations to dope the films. The prepared films were transparent and therefore studied for application in photonics. Optical characterization of the samples was carried out using different spectroscopy techniques. Absorption spectra for both samples were obtained using a UV–vis light spectrophotometer. Other significant optical parameters, such as refractive index, extinction coefficient, and band gap energies, were calculated from the absorption spectra. The effect of doping concentration on these parameters was studied. Emission spectra were obtained using a fluorescence spectrophotometer and the effect of doping was observed. Fourier transform infrared spectra of the doped films were obtained and compared with the pure compound to note changes in peak values and peak intensity. This present work studied the effect of doping on optical properties and examined the application of the samples for photonics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.