"Radiation Synthesis of Polyaniline Based Compounds and their Potential Applications"
Noha Mohamed Deghiedy;
Abstract
The present study is divided into two parts:
First part: In-situ formation of conductive polyaniline thin skins onto radiation grafted polypropylene films (PP-g-PAA)/PANI.
Second part: Gamma radiation enhancement of photocatalytic activity of conducting polyaniline–TiO2 nanocomposites (PANI-TiO2) for degradation of methyl orange dye (MO) under visible light.
The results obtained can be summarized as follows:
I) In-situ Formation of Conductive Polyaniline Thin Skins onto Radiation Grafted Polypropylene Films (PP-g-PAA)/PANI:
1- High energy radiation processing was applied to polypropylene films in order to graft functional groups on the otherwise chemically inert material that could promote the formation of a chemically bonded polyaniline.
2- Electronic absorption spectra of pristine PP films, confirmed the optical transparency and colorless appearance of all the substrates, except ortho and meta substituted phenylenediamines, which imparted the yellow color for their characteristic absorption in the blue range (430-480 nm).
3- For all grafted and functionalized films after polymerization of aniline, a typical broad absorption peak in the visible range, peaking at ~800 nm and above, with a long tail extending toward the near-IR region was observed.
4- For all systems, the -* transition peak of benzenoids, appeared at 420-430 nm.
5- When PANI-ES was converted into its base forms, the polarone absorption peak was replaced by the peak at about 540-570nm.
6- The treatment with NMP, which removed the emeraldine base which was not attached to the substrate, caused a significant reduction in optical density of electronic spectra of all systems.
7- FTIR analysis was carried out on polypropylene films after each derivatisation step, as well as on all the hybrid skin–core PP-g-PAA/PANI films confirmed the success of each step of treatment.
8- Radiation grafting of acrylic acid introduced a vibration band at 1716 cm-1 which was replaced by the stretching vibration of acyl chloride groups at 1790 cm-1 after treatment with SOCl2.
9- Derivatisation with any of the diamines caused disappearance of the band at 1790 cm-1 and the appearance of two new strong bands at about 1670 and 1575cm-1.
10- The FTIR spectra of the PANI films as prepared showed the appearance of 1552, 1462, 1165 and 850 cm−1 which indicated the formation of PANI in its doped form.
11- The analysis of both the topographical features of the films surface and the morphology of their cross-sections, as obtained by shearing the films in liquid nitrogen after cutting a small pre-crack opening were investigated by Scanning electron microscopy (SEM).
12- SEM images showed that the surface of PP films appears rather smooth and featureless, while after deposition of polymerized AA monomer on the surface became much rougher.
13- It could be noticed that the first treatment, with thionyl chloride, didn't induce modifications of the surface morphology of PP-g-PAA substrates. Moreover, the treatment with different amines didn't not significantly change the morphology.
14- Contrariwise, the presence of PANI coatings on the polymeric substrates induced a drastic change of surface morphology, from smooth to granular at the nanoscale.
15- The electrochemical behaviour of the PP-g-PAA/PANI for the functionalized films was investigated by cyclic voltammetry in the potential range between −0.6 and +0.8V in 1.0M HCl solution.
16- The voltammogram recorded at 100mV/s for the PP-g-PAA/PANI functionalized films under nitrogen flux: in the forward scan (from the open-circuit potential towards positive potentials) an oxidation peak occurs; whilst in the reverse scan was present.
17- It was apparent from the impedance spectroscopy results that electrical properties of the composite films changed strongly depending on the amine group used for the functionalization.
18- The electrical conductivities of the corresponding PP-g-PAA functionalized films after polymerization of PANI in the doped state (PANI-ES) were higher than those before PANI, by approximately 9 orders of magnitude reaching 6.3x10-3.
19- The growth process of polyaniline (PANI) during the electrochemical polymerization resulted in an increment in the conductivity of the functionalized film reaching 0.3x10-1 S/cm.
20- It can be concluded from the previous results that the PP-g-PAA/PANI functionalized hybrids have potential application in the field of antistatic packaging of electronic devices.
First part: In-situ formation of conductive polyaniline thin skins onto radiation grafted polypropylene films (PP-g-PAA)/PANI.
Second part: Gamma radiation enhancement of photocatalytic activity of conducting polyaniline–TiO2 nanocomposites (PANI-TiO2) for degradation of methyl orange dye (MO) under visible light.
The results obtained can be summarized as follows:
I) In-situ Formation of Conductive Polyaniline Thin Skins onto Radiation Grafted Polypropylene Films (PP-g-PAA)/PANI:
1- High energy radiation processing was applied to polypropylene films in order to graft functional groups on the otherwise chemically inert material that could promote the formation of a chemically bonded polyaniline.
2- Electronic absorption spectra of pristine PP films, confirmed the optical transparency and colorless appearance of all the substrates, except ortho and meta substituted phenylenediamines, which imparted the yellow color for their characteristic absorption in the blue range (430-480 nm).
3- For all grafted and functionalized films after polymerization of aniline, a typical broad absorption peak in the visible range, peaking at ~800 nm and above, with a long tail extending toward the near-IR region was observed.
4- For all systems, the -* transition peak of benzenoids, appeared at 420-430 nm.
5- When PANI-ES was converted into its base forms, the polarone absorption peak was replaced by the peak at about 540-570nm.
6- The treatment with NMP, which removed the emeraldine base which was not attached to the substrate, caused a significant reduction in optical density of electronic spectra of all systems.
7- FTIR analysis was carried out on polypropylene films after each derivatisation step, as well as on all the hybrid skin–core PP-g-PAA/PANI films confirmed the success of each step of treatment.
8- Radiation grafting of acrylic acid introduced a vibration band at 1716 cm-1 which was replaced by the stretching vibration of acyl chloride groups at 1790 cm-1 after treatment with SOCl2.
9- Derivatisation with any of the diamines caused disappearance of the band at 1790 cm-1 and the appearance of two new strong bands at about 1670 and 1575cm-1.
10- The FTIR spectra of the PANI films as prepared showed the appearance of 1552, 1462, 1165 and 850 cm−1 which indicated the formation of PANI in its doped form.
11- The analysis of both the topographical features of the films surface and the morphology of their cross-sections, as obtained by shearing the films in liquid nitrogen after cutting a small pre-crack opening were investigated by Scanning electron microscopy (SEM).
12- SEM images showed that the surface of PP films appears rather smooth and featureless, while after deposition of polymerized AA monomer on the surface became much rougher.
13- It could be noticed that the first treatment, with thionyl chloride, didn't induce modifications of the surface morphology of PP-g-PAA substrates. Moreover, the treatment with different amines didn't not significantly change the morphology.
14- Contrariwise, the presence of PANI coatings on the polymeric substrates induced a drastic change of surface morphology, from smooth to granular at the nanoscale.
15- The electrochemical behaviour of the PP-g-PAA/PANI for the functionalized films was investigated by cyclic voltammetry in the potential range between −0.6 and +0.8V in 1.0M HCl solution.
16- The voltammogram recorded at 100mV/s for the PP-g-PAA/PANI functionalized films under nitrogen flux: in the forward scan (from the open-circuit potential towards positive potentials) an oxidation peak occurs; whilst in the reverse scan was present.
17- It was apparent from the impedance spectroscopy results that electrical properties of the composite films changed strongly depending on the amine group used for the functionalization.
18- The electrical conductivities of the corresponding PP-g-PAA functionalized films after polymerization of PANI in the doped state (PANI-ES) were higher than those before PANI, by approximately 9 orders of magnitude reaching 6.3x10-3.
19- The growth process of polyaniline (PANI) during the electrochemical polymerization resulted in an increment in the conductivity of the functionalized film reaching 0.3x10-1 S/cm.
20- It can be concluded from the previous results that the PP-g-PAA/PANI functionalized hybrids have potential application in the field of antistatic packaging of electronic devices.
Other data
| Title | "Radiation Synthesis of Polyaniline Based Compounds and their Potential Applications" | Other Titles | التحضير الإشعاعي لبعض مركبات البولي أنيلين وتطبيقاتها الممكنة | Authors | Noha Mohamed Deghiedy | Issue Date | 2015 |
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