Reaction of ozone with polybenzimidazole (PBI)

Omar, Omran; Ha, B.; Vega, Katerine; Fleischer, Andrew; Moon, Hyukin; Shertok, Joel; Bailey, Alla V; Mehan, Michael; Gupta, Surendra K.; Takacs, G. A.

doi:10.1080/01919512.2018.1446127

Cited by 7 publications

(9 citation statements)

References 29 publications

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“…Moreover, their capacity for forming a charge-transfer complex also promoted the UV resistance of materials. , As shown in Figure B, PI-8/2 also shows superior ozone aging resistance, as kept at 95% and 85% of initial tensile strength and break extension of pristine PI fibers, separately. Interestingly, the modulus of the PI-8/2 fiber improved after 175 h ozone aging compared to that of the untreated sample, which may be arisen from the fact that a cross-linking reaction occurs between imidazole ring and phenyl group by losing water in polymer chains. − Furthermore, scanning electron micrographs were used to obtain detailed reasons that why the PI-8/2 fiber exhibits better UV irradiation resistance and ozone aging resistance. As shown in Figure , the untreated PI-8/2 fiber (Figure L) shows a glazed and dense surface morphology, which turns into brightness with metallic luster after 175 h of ozone aging (Figure D) and shows much smooth after 168 h of UV irradiation (Figure H).…”

Section: Resultsmentioning

confidence: 99%

High-Strength and High-Modulus Polyimide Fibers with Excellent UV and Ozone Resistance

Zheng

Dong

Zhou

et al. 2022

ACS Appl. Polym. Mater.

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A series of high-strength and high-modulus polyimide (PI) fibers containing benzimidazole and biphenyl units were synthesized from 2-(4-aminophenyl)-5-aminobenzimidazole (BIA), p-phenylenediamine (PDA), and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA). The dry-spinning and hot-drawing processes were used to prepare PI fibers with various PDA/BIA molar ratios, wherein the chemical structures were identified by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Additionally, the relationship between the mechanical properties and aggregation structure of obtained PI fibers, varying with diamine ratios and hot-drawing ratios, was demonstrated by two-dimensional wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS), showing that the variation trend of mechanical property has a strong consistency with the nanoscale orientation factor calculated by the SAXS. The optimum tensile strength and modulus of PI fibers are 4.3 and 145 GPa, respectively, at a PDA/BIA molar ratio of 8/2. Moreover, after 168 h of UV irradiation and 175 h of ozone aging, this sample shows an excellent UV irradiation resistance and ozone aging resistance with retaining 94% and 95% of tensile strength of the pristine fiber. Meanwhile, the prepared PI fibers exhibit prominent thermal stabilities with the 10% weight loss temperature over 590 °C in a nitrogen atmosphere.

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Section: Resultsmentioning

confidence: 99%

High-Strength and High-Modulus Polyimide Fibers with Excellent UV and Ozone Resistance

Zheng

Dong

Zhou

et al. 2022

ACS Appl. Polym. Mater.

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“…The reaction of ozone with PBI was previously studied in the absence of radiation, where the ozone was made by an electric generator [24]. Decomposition of the primary ozonides formed by the addition of ozone to the C=C and C=N bonds, and reaction with the amine groups in PBI, decreased the C-C sp 2 and C=N functional groups and increased the presence of C-N, N-C=O, and the carbonyl-containing moieties, as observed in this study (Tables 1 and 2).…”

Section: Discussionmentioning

confidence: 99%

“…Washing the treated PBI surface with distilled water decreased the saturation level for oxygen from 20.2 ± 0.7 at % down to 17.7 at %, indicating the partial formation of a weak boundary layer due to the breakage of bonds by the UV radiation and decomposition of the primary ozonide. Ozone, produced by the electric generator, resulted in a greater decrease with washing from 27 ± 1 down to 13 at % O and larger concentrations of the anhydride group, O=C-O-C=O, which is the most oxidized form of carbon that releases CO 2 [24].…”

Section: Discussionmentioning

confidence: 99%

UV Photo-Oxidation of Polybenzimidazole (PBI)

et al. 2020

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Since polybenzimidazole (PBI) is often used in the aerospace industry, high-temperature fuel cells, and in redox flow batteries, this research investigated the surface modification of PBI film with 253.7 and 184.9 nm UV photo-oxidation. As observed by X-ray photoelectron spectroscopy (XPS), the oxygen concentration on the surface increased up to a saturation level of 20.2 ± 0.7 at %. With increasing treatment time, there were significant decreases in the concentrations of C-C sp2 and C=N groups and increases in the concentrations of C=O, O-C=O, O-(C=O)-O, C-N, and N-C=O containing moieties due to 253.7 nm photo-oxidation of the aromatic groups of PBI and reaction with ozone produced by 184. 9 nm photo-dissociation of oxygen. Because no significant changes in surface topography were detected by Atomic Force Microscopy (AFM) and SEM measurements, the observed decrease in the water contact angle down to ca. 44°, i.e., increase in hydrophilic, was due to the chemical changes on the surface.

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“…This study was conducted similar to the reaction of ozone with polybenzimidazole (PBI) [18] where oxygen with a flow rate of 2.5 l/h was fed into an Enaly Ozone Generator model 1000BT-12 (Shanghai, China), which contains a corona discharge tube, to convert about 6 ± 2% of the volume of oxygen into ozone. The ozone/oxygen mixture was then flowed over the sample in a quartz cylindrical cell with the exiting gas passed through a solution of KI to convert the remaining ozone to oxygen before emission into the vacuum hood.…”

Section: Production Of Ozonementioning

confidence: 99%

“…However, at this high temperature, there is loss of H3PO4 decreasing the performance of the fuel cell [14][15][16][17]. Therefore, to increase wettability and proton conductivity, surface oxidation of the aromatic groups in PBI were studied with ozone [18], O atoms [19], UV photo-oxidation [20], and vacuum UV photo-oxidation [21]. In addition, the performance of a phosphoric acid fuel cell with n-hexadecane fuel has shown promise for petroleum diesel or biodiesel fuels [22].…”

Section: Introductionmentioning

confidence: 99%

Enhancing the Wettability of Polyetheretherketone (Peek) Membrane with Ozone for Improving Fuel Cell Performance

Heineman¹,

Omar²,

Rippel³

et al. 2022

J Energ Power Technol

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Ozone was reacted with the aromatic membrane polyetheretherketone (PEEK) to form oxidized functional groups on the surface to enhance the attraction and transport of protons in fuel cells. Ozonation of unsaturated C-C sp<sup>2</sup> bonds in PEEK formed a primary ozonide which dissociated to primarily produce O=C-O/O=C-OH moieties, and the root mean squared roughness factor (R<sub>q</sub>) decreased from 7.4 nm, for the untreated sample, down to 3.1 nm. The oxidation of the surface and decrease in surface roughness made the surface increase in hydrophilicity as observed by the decrease in the water contact angle (CA) from 80.3° for untreated PEEK down to 21.7°. Washing the treated surface with solvent decreased the O at % on the surface indicating the formation of a weak boundary layer because of bond breakage during the decomposition of the ozonide.

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Reaction of ozone with polybenzimidazole (PBI)

Cited by 7 publications

References 29 publications

High-Strength and High-Modulus Polyimide Fibers with Excellent UV and Ozone Resistance

High-Strength and High-Modulus Polyimide Fibers with Excellent UV and Ozone Resistance

UV Photo-Oxidation of Polybenzimidazole (PBI)

Enhancing the Wettability of Polyetheretherketone (Peek) Membrane with Ozone for Improving Fuel Cell Performance

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