Molar Ratio Of Aniline Research Articles

Controlled growth of redox-active polymer nanorods on MOF-derived activated nanoporous carbons: 3D reconstruction study and high-performance supercapacitor

Supercapacitors, which a energy storage systems, have been continuously studied because of their high power density and rapid charging-discharging capacity. Supercapacitors can be classified into pseudocapacitors and electric double-layer capacitors (EDLCs). The effective utilization of these two supercapacitor mechanisms is important for achieving high performance. In this study, highly nanoporous metal–organic framework (MOF)-derived carbon underwent chemical activation with potassium hydroxide to produce a high surface area. Subsequently, activated carbon was combined with a polyaniline (PANI) nanoarchitecture to introduce redox-active sites. Activated MOF-derived carbon provides a high specific surface area for EDLCs, and well-controlled PANI nanorods support large amounts of redox-active sites to achieve high capacitance. The aniline (ANI) concentration, growth time, acid, temperature, and ammonium persulfate (APS):ANI molar ratio were controlled to grow PANI nanorods without aggregation. At a scan rate of 5 mV/s, the capacitance of the PANI-ZIF-8-derived carbon composite reached 635.3 F/g, which was superior than that of ZIF-8-derived carbon (143.4 F/g). It also exhibited excellent durability during cycling, demonstrating that it can serve as a high-performance hybrid electrode material composed of carbon and polymer for supercapacitors.

Synthesis of Quinolines by the Skraup Reaction: Hierarchical Zeolites vs Microporous Zeolites

AbstractThe activity, selectivity, and stability of microporous highly dispersed zeolites (H‐Y, H‐ZSM‐5) and granulated hierarchical zeolites (H‐Yh and H‐ZSM‐5h) were studied in the synthesis of quinolines by the Skraup reaction. Texture, porous structure, morphology of crystals, acidic properties were characterized by XRD, XRF, N2 adsorption‐desorption, SEM, NH3‐TPD methods. It was found that quinoline, 2‐ and 4‐methylquinolines are the main products in the reaction of aniline with glycerol in the presence of the studied catalysts. H‐ZSM‐5h and H‐Yh catalysts are more efficient than catalysts H‐ZSM‐5 and HY and provide a yield of quinolines to 72.4 (H‐ZSM‐5h) and 60.2 % (H‐Yh) at 450 °C, 0.2 h−1, the molar ratio of aniline:glycerol=1 : 3. The high activity and selectivity of hierarchical zeolites are due to the presence of meso‐ and macropores, as well as nanocrystals of 15–100 nm size. It was reported that hierarchical catalysts exhibit higher stability in the reaction compared with microporous zeolites.

Development of grafted rubber/polyaniline/carboxymethyl cellulose film as green conductive polymer film

Conducting polymer film has been found to be good alternative for conventional metal film in the application of flexible conductors for stretchable electronics. This research aims to produce green conductive polymer film with good mechanical and electrical performance through incorporation of polyaniline (PAni) as conductive material and carboxymethyl cellulose (CMC) as natural reinforcing filler in grafted rubber host. Different molar ratios of aniline (Ani) monomer and docusate sodium salt purum (AOT) dopant were used to produce PAni:AOT of molar ratio 5:3, 5:5 and 5:7. Grafted rubber/PAni/CMC films were synthesised using ex situ polymerisation and characterized by FTIR, XRD and SEM analyses. The mechanical and electrical performances were studied via universal tensile machine and resistivity meter, respectively. Incorporation of PAni in polymer films improved the electrical conductivity from 0 S cm−1 (MG49/CMC) to 1.388 $$\times$$ 10–7–1.807 $$\times$$ 10–2 S cm−1 (MG49/PAni/CMC). Addition of CMC enhanced the mechanical performances of the films with improved tensile strength and Young modulus from 8.0 (MG49/PAni 5:7) to 9.2–12.1 MPa (MG49/PAni 5:7/CMC) and 279 MPa (MG49/PAni 5:7) to 401–630 MPa (MG49/PAni 5:7/CMC), respectively. In conclusion, mechanical performance and electrical conductivity range of the synthesized conductive polymer film of MG49/PAni 5:7/CMC fulfil the recommended mechanical and electrical performance range of traditional and commercial conductive films.

Novel three-dimensional renewable phytic acid based aerogel electronics

Novel three-dimensional renewable phytic acid (AP) aerogel electronics were synthesized through in-site polymerization and oriented lyophilization method. Three stages of the aerogels were apparently observed via SEM and TEM tests: the honeycomb structure consituted the first stage; the network with micropores formed the second stage; the third stage was composed of nanopores structure inside the micropores. When the molar ratio of aniline and phytic acid reached certain degree, the AP aerogel will emerge high pore volume and excellent specific capacitance. What’s more, the mechanical properties of AP aerogel were about 5 times (9 times for electrical properties) higher in vertical direction than those in horizontal direction. To sum up, the three-dimensional AP aerogel owned great mechanical and electrical properties in specific direction, at the same time, it exhibited outstanding specific capacitance (448 F.g-1).

Formation of Carbazole in ɤ- irradiated Aniline / Chlorobenzene mixtures

In this study, Gas chromatographic/mass spectrometric study indicated that carbazole (CARB) is formed in oxygen free ɤ- irradiation of aniline / chlorobenzene mixtures. It seems that ɤ-radiation induces the formation of CARB in these mixtures via intramolecular dehydrocyclization of diphenylamine (DPA). The yield of CARB estimated via gas chromatography (GC), was found to be dependent on aniline – chlorobenzene molar ratio. Where, the maximum CARB yield was found at 1:1 molar ratio of aniline – chlorobenzene. At this reactants molar ratio, the effect of absorbed radiation dose and dose rate on the yield of carbazole was studied. The yield of CARB increases, linearly, as the absorbed dose is increased up to about 50 kGy. The G-value (5.8μM/J) of CARB was determined. It was found that, the yield of CARB increase as the absorbed dose rate increases (0.226 -0.904kGy/h). So, it can be concluded that CARB is formed, mainly, in the spurs. The mechanism of the CARB formation was discussed.

Composite Nanofibers by Growing Polypyrrole on the Surface of Polyaniline Nanofibers Formed under Free Melting Condition and Shell-Thickness-Dependent Capacitive Properties

An efficient approach was presented to prepare polyaniline/polypyrrole (PANi/PPy) composite nanofibers by growing PPy layers on the surface of PANi nanofibrous seeds as electrode materials for supercapacitors in neutral electrolyte. Core layer of PANi nanofiber was firstly synthesized by the chemical oxidative polymerization of aniline monomers under free melting condition of reaction solutions in fully aqueous system without the assistance of any templates or organic solvents. Then the shell layer of PPy was fabricated by in-situ chemical oxidative polymerization of pyrrole monomers with the above-mentioned PANi nanofiber as a seed, and the PPy shell layer thicknesses were tuned by changing the molar ratio of aniline to pyrrole. The resulting PANi/PPy composites were investigated by field-emission scanning electron microscopy, ultraviolet-visible spectroscopy, Fourier transform infrared and Raman spectrometry. Furthermore, electrochemical behaviors in Na2SO4 electrolyte were tested by cyclic voltammetry, galvanostatic charge-discharge techniques and electrochemical impedance spectroscopy. It turned out that low molar ratio of aniline to pyrrole is helpful to increase the PPy shell layer thicknesses, yield and conductivity of PANi/PPy composite nanofibers. A great improvement on the capacitive properties could be achieved by choosing appropriate PPy shell layer thickness. The results showed that benefiting from strong synergy effect and π-π interaction between PANi core and PPy shell layer as well as low electrochemical impedance, PANi/PPy composite nanofibers prepared with the molar ratio of 1:1 (PPy shell layer thickness of about 12.5 nm) displayed the highest specific capacitance of 1550.2 F g−1 at scan rate of 5 mV s−1 and 758.8 F g−1 at the current density of 1 A g−1 with the best cycling stability of 70.3 % after 500 cycles in 0.5 M Na2SO4 electrolyte, which exhibited a great potential in the development of high-performance electrode materials operated in environmentally friendly electrolyte.

Synthesis and characterization of polyaniline nanomaterials with different molar ratio of monomer


 
 
 Formation of polymer nanomaterials are achieved by the process of polymerization and there was an availability of different methods such as chemical oxidative polymerization,electro chemical polymerization, In-situ oxidative polymerization and emulsion polymerization etc., Many monomers combine to form polymers under certain conditions by chemical reactions between the monomers. The chemical oxidative polymerization was most commonly used method to synthesize PANI and the synthesis process involved various molar ratio of aniline (0.1M, 0.2M, 0.3M) in which APS was used as an oxidant with dopant of HCl. This study revealed that the properties changed based on their initial conditions. The prepared aromatic polyaniline was characterized by FT-IR, UV-VIS,Particle size analyzer techniques and anti-bacterial activity of the sample was analyzed.FT-IR spectroscopy gives deep view of many functional groups that were present in a system by measuring vibrational frequencies of chemical bonds involved. UV-VIS was a good tool to identify, characterize and to study the optical properties of nanomaterials.In particle size analyzer, the size of a particle was measured using the instrument laser diffraction particle size analyzer (SALD-2300). The synthesized polyaniline had the tendency to resist the growth of both gram positive and gram negative bacteria. These organic conducting polymers were sometimes called “smart polymers” and have varies application in medical, OLED, solar cell, batteries and sensor etc.,
 
 

Polyaniline-Modified TiO2, a Highly Effective Photo-catalyst for Solid-Phase Photocatalytic Degradation of PVC

A series of polyaniline-modified TiO2 photo-catalysts (TiO2@PANI) were prepared via an in-situ polymerization of aniline onto TiO2 nanoparticles. The Fourier-transform infrared spectroscopy (FT-IR) and thermogravimetric analyses (TGA) confirmed that the polyaniline (PANI) successfully grafted on the TiO2 NPs. The X-ray diffraction (XRD) patterns showed that the crystalline structure of the TiO2 did not change during the preparation of PANI. Photodegradable nanocomposites were prepared by embedding the photocatalysts into the commercial poly(vinyl chloride) (PVC) samples. The nanocomposite films were compared against pure PVC and PVC-TiO2 films for their photodegradation performances. The photocatalytic activity of the TiO2@PANI catalysts improved with an increase in the inorganic/organic molar ratio. With the TiO2 aniline molar ratio of 10, the PVC-TiO2@PANI nanocomposite film lost about 67% of its weight after 720 h irradiation under UV. Meanwhile, the pure PVC and PVC-TiO2 control films lost about 12 and 45% of their initial weights, respectively. Results showed that the rate at which the PVC is photodegraded can be controlled by the amount of the TiO2 NPs as well as the initial TiO2 aniline molar ratio. The SEM micrograms indicated a rougher and more porous surface for the irradiated PVC-TiO2@PANI compared with controls.

Synthesis of pyrroles catalyzed by MIL-53(Al) via Paal-Knorr reaction under mild condition

Metal-organic framework MIL-53(Al) was synthesized by a solvothermal method using aluminium nitrate as the aluminium source and 1,4- benzenedicarboxylic acid (H2BDC) as the organic ligand. The structure of MIL-53(Al) was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The catalytic activity and recyclability of MIL-53(Al) catalyst were evaluated based on the Paal-Knorr reaction between aniline and acetonylacetone. The reaction conditions were optimized and the results showed that the MIL-53(Al) catalyst exhibited good catalytic activity and recyclability based on the PaalKnorr reaction. With the molar ratio of MIL-53(Al) catalyst of 10 mol %, the molar ratio of aniline and acetonylacetone of 1:1.2, and without solvents, the conversion of aniline could reach 100 % and the selectivity of 2,5-dimethyl-1-phenyl-1H-pyrrole has high yield (95-100 %) after 2 hours by ultrasound activation. The MIL-53(Al) catalyst can be reused five times without significant degradation in the catalytic activity.

Synthesis and Characterization of TNTs/Polyaniline Composite as Photocatalyst Degradation of Rhodamin B by Visible Light

<p>The purpose of this research is to study the effect of the amount of aniline on their photocatalytic activity. Nano TiO<sub>2</sub> was synthesized using sol-gel method with TiPP precursor. XRD characterization results showed that nano TiO<sub>2</sub> with calcination temperature of 450 °C had size of 13.8 nm with high crystalline. The diffraction peaks of nano TiO<sub>2</sub> at 2θ are 24.45°; 37.075°; 47.26° and 53.18°. Nano TiO<sub>2</sub> was then synthesized with hydrothermal treatment 24 h of 140 °C to produce TNTs. The results of XRD analysis shows anatase phase with field (004) and (200). The morphology of TNTs begins to form at the calcinations temperature of 600 °C with textural coefficient value of 0.998 3 . Synthesis of composite TNTs/PANI (polyaniline) was done by in situ polymerization technique of aniline which was already contained nano TiO<sub>2</sub>. The molar ratio of aniline and APS in the synthesis of a composite is 1:1.5 with the addition of aniline of 15 %; 20 % and 25 % (w/w %). Characterization using FTIR showed the stretching vibration of the C=N in wavelength of 1 600 cm<sup>–1</sup> to mark the formation of quinonoid compounds of polyaniline. The test of the rhodamine B degradation gave the best results on the 25 % TNTs/PANI composite, with the degradation percentage of 58.73 %. The characterization results using dr-uv proved that the decrease of energy gap in the TNTs/PANI composite which as evidenced with Kubelka-Munk calculation equation that was 25 % TNTs/PANI amounting to 3.19 eV and TNTs at 3.24 eV.</p>

Synthesis, characterization and optimization of N‐TiO2/PANI nanocomposite for photodegradation of acid dye under visible light

Polyaniline (PANI) as an excellent conducting polymer was used to prepare an organic–inorganic hybrid nanocomposite based on nitrogen (N)‐doped titanium dioxide (TiO2) under different synthesis conditions. Based on the DRS, XRD, FESEM, BET, XPS, and FT‐IR results, the optical and structural properties of the as‐prepared composites were found to be affected by N‐TiO2 to aniline (ANI) molar ratio, reaction time, and initial pH of solution, which in turn influence the photocatalytic performance of nanocomposites. The experimental design methodology was used to study the simultaneous effect of these synthesis parameters on the Vis activity performance of N‐TiO2/PANI nanocomposites for degradation of Acid Red 73. The degradation efficiency was significantly affected by the reaction time of polymerization, initial pH of solution, and interaction between the reaction time and N‐TiO2/ANI molar ratio. The optimal synthesis conditions for maximum Acid Red 73 degradation efficiency (58.25%) were found to be a molar ratio of N‐TiO2/ANI of 106.13 M, the reaction time of 487.42 min, and pH of 3.37. TEM images, N2 adsorption–desorption isotherms and BET analysis of the as‐prepared nanocomposites show the increase in surface area and porosity and decrease in agglomeration formation by adding nitrogen and PANI. The N‐TiO2/PANI nanocomposites prepared at optimal synthesis conditions show higher visible activity compared to those modified with nitrogen or PANI only due to the synergistic effect between PANI and N doping. The mineralization studies of Acid Red 73 using the as‐prepared nanocomposites show their ability to decompose approximately all organic compounds present in the solution. POLYM. COMPOS., 39:4605–4616, 2018. © 2017 Society of Plastics Engineers

Synthesis and characterization of conductive polyaniline nanocomposite containing fluorene

Fluorene, an excellent electroluminescent material, has been used as a core to synthesize a core–shell fluorene/polyaniline (fluorene/PANI) composite using ammonium persulfate as an oxidant. The influence of the fluorene–aniline molar ratio and the oxidant–aniline molar ratio on the resistance of the composite was investigated, and the crystallinity, structure, and morphology of the fluorene/PANI composite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The results indicate that the fluorene/PANI composite has a core–shell structure and exhibits good conductivity. A more planar conformation of PANI could be formed because of strong π–π interactions between the fluorene core and the PANI shell.

One-step and template-free synthesis of itaconic acid–doped polyaniline nanorods in aqueous solution

With itaconic acid as dopant and (NH4)2S2O8 as oxidant, itaconic acid–doped polyaniline (PANI) nanorods were prepared by one-step and template-free polymerization method. The influence of the polymerization parameters such as the oxidant–aniline molar ratio, the oxidant concentration, the molar ratio of itaconic acid and aniline, and the itaconic acid concentration on the yield and conductivity of PANI was investigated by single factor analysis method. The yield and conductivity of itaconic acid–doped PANI were 112.5% and 2.06 × 10−3 S cm−1, respectively, when synthesized under the optimal reaction condition at room temperature. From the Fourier transform infrared and ultraviolet visible spectra, it can be demonstrated that PANI was successfully doped by itaconic acid and the conductivity was maximum when the ratio of benzene ring and quinine ring was 3:1 and the doping ratio of quinine ring reached 50%. Microstructure images showed that PANI has nanosized rod-like morphology.

Copolymers of Aniline with O-Anthranilic Acid: Synthesis and Characterization

Chemical copolymerization of aniline with o-anthranilic acid in aqueous 1 M HCl was carried out at different molar ratios of aniline and o-anthranilic acid, and was characterized by FTIR and UVVisible spectroscopy, elemental analysis and electrical conductivity. From FTIR and UV-Visible spectroscopy, we observed that o-anthranilic acid had been introduced into the polymer chain successfully. The percent yield of o-anthanilic acid copolymer with aniline decreases as the percent of aniline increases. An increase in the % C can be observed as the amount of o-anthranilc acid in the copolymer decrease or the amounts of aniline increase. Copolymerization of aniline with o-anthranilic acid would improve the resulting polymer via increasing the molecular weight and the conductivity as well.

Soluble polyaniline nanofibers prepared via surfactant-free emulsion polymerization

Polyaniline nanofibers were successfully prepared using fumaric acid as the dopant and ammonium peroxydisulfate as the oxidant via surfactant-free emulsion polymerization. The influence of the polymerization parameters such as the oxidant–aniline molar ratio, the oxidant concentration, the molar ratio of fumaric acid and aniline and the fumaric acid concentration on the yield and conductivity of polyaniline was investigated on the basis of the orthogonal experimental method. The morphology, crystallinity, chemical structure and thermal stability of fumaric acid-doped polyaniline prepared under the optimal polymerization condition and the undoped polyaniline were characterized. The results demonstrated that fumaric acid-doped polyaniline has the morphology of nanofibers with a dense array of nodules, an excellent solubility in organic solvents, higher crystallinity, partially doping state and good thermal stability. But the undoped polyaniline formed granular particle agglomerations in a nearly amorphous state upon dedoping.

Synthesis and Characterization of Polyaniline–Mn3O4 Nanocomposite: Electrical Conductivity and Magnetic Studies

Polyaniline (PANI)–Mn3O4 nanocomposites (NCs) have been synthesized by in situ chemical oxidative polymerization of aniline with different molar ratios of aniline:Mn3O4 (3.3:1 and 2.5:1) using ammonium per sulfate as an oxidant in an aqueous solution of sodium dodecyl benzene sulfonic acid, as surfactant and dopant at 5 °C under N2 atmosphere. The structural components and the crystalline phase of the Mn3O4 nanoparticles (NPs) and PANI–Mn3O4 NCs were identified from Fourier transform infrared spectroscopy and X-ray diffraction. The result of FTIR and TGA shows that the interaction between Mn3O4 particles and PANI matrix could improve the thermal stability of NCs. The room temperature electrical conductivity of the synthesized PANI, PANI-Mn3O4 NCs (3.3:1) and (2.5:1) was found to be 3.26 × 10−4, 8.11 × 10−7 and 3.93 × 10−7 S/cm respectively, indicating the decrease of conductivity with an increase of Mn3O4 content in PANI. The magnetic behavior of composite was studied at 5 K. The coercive force (Hc) and remnant magnetization (Mr) increases with increase in addition of Mn3O4 NPs in PANI matrix.

Structure-Property Relationship of Dodecylbenzenesulfonic Acid Doped Polyaniline

Dodecylbenzenesulfonic acid (DBSA) doped polypanilines (PANIs) were chemically synthesized in different molar ratios of aniline (An) to ammonium persulfate (APS) and An to DBSA. The microstructures of these PANIs were investigated by means of scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared (FTIR). UV-Vis spectrometer, semiconductor parameter analyzer, ubbelohde viscometer and electrospinning technique were used to characterize the optical, electrical properties, viscosity and solubility of these PANIs. The results show that the molar rations of An to APS and An to DBSA had strong effect on the microstructure, molecular weight, degree of crystallinity, optical property, solubility and conductivity of obtained DBSA doped PANI. With the increase of the molar ratios of An to APS and An to DBSA, the conductivities and molecular weight of DBSA doped PANIs decreased, while the degree of crystallinity and solubility of DBSA doped PANIs increased. The DBSA doped PANI could dissolve in dichloromethane or HFIP and could be fabricated short fibers by electrospinning. Moreover, the solution of DBSA doped PANIs in concentrated sulphuric acid showed liquid crystal property.

Processable polyaniline/titania nanocomposites with good photocatalytic and conductivity properties prepared via peroxo-titanium complex catalyzed emulsion polymerization approach

The homogeneous polyaniline (PAni)/TiO2 nanocomposites were successfully synthesized via a facile emulsion polymerization with the assistance of peroxo-titanium complex (PTC), where PTC was used as both the TiO2 precursor and the oxidant for the polymerization of PAni/TiO2 nanocomposites. Comprehensive analysis indicated that anatase TiO2 nanocrystals (about 4–6nm) were well-dispersed in the PAni chains without aggregation, and the TiO2 were anchored on the polymer chains through chemical interactions, such as TiONC and TiOC, which made the PAni/TiO2 composite possess better thermal stability. The PAni/TiO2 composite could be well dispersed in common solvent, such as acetone, and stay stability without any precipitation for a month. Since the PAni/TiO2 composite could be well dispersed in common solvent, the PAni/TiO2 dispersion may be coated on the surface of Poly (ethylene terephthalate) (PET) film, showing good processable properties, and the prepared PAni/TiO2/PET films exhibit good photocatalysis and best conductivity (2.08×10−2scm−1), when the molar ratio of aniline (AN) and Ti in the PAni/TiO2 composite is 1/1. The possible reaction mechanism was also discussed. The facile synthesized method proposed can also be used for the preparation of other conducting polymer/semiconductor nanocomposites.

Facile synthesis of high-quality ultralong poly(aniline-co-p-phenylenediamine) nanofibers

High-quality ultralong poly(aniline-co-p-phenylenediamine) nanofibers have been synthesized successfully by one-step chemical copolymerization of aniline and p-phenylenediamine using ammonium peroxydisulfate as the oxidant in aqueous solution. The addition of p-phenylenediamine in conventional polymerization system plays an important role in changing the bulk morphologies of polyaniline from irregular particle agglomerates to nanofibers. This process is rapid, facile, and free of any template and surfactant. The influences of synthetic parameters, such as the molar ratios of aniline and p-phenylenediamine, the molar ratios of monomer and ammonium peroxydisulfate, and the concentrations of HCl, on the morphologies and molecular structures of the resulting products have been investigated for elucidating the formation mechanism of poly(aniline-co-p-phenylenediamine) nanofibers.

Protection of stainless steel by the electrodeposition of polyaniline/poly(o-phenylenediamine) composite layers

Three polyaniline (PANI)/poly(o-phenylenediamine) (PoPD) mixtures have been electrochemically deposited on a stainless steel surface from an acidic solution. Electrocopolymerization was favorable at high molar ratios of aniline to o-phenylenediamine, and the resulting copolymer is a random type. Two bilayers, PoPD/PANI and PANI/PoPD, were prepared by successive electrodeposition, during which different multiphase structures were obtained. The presence of PoPD with PANI in the copolymer or multilayer structures enhances the passivation of the SS. The bi-layer coating in which a PANI layer lies under the PoPD produced the best passive oxide on the SS. The resistance to pitting increases with the coating order as follows: PANI < copolymer ≪ PANI/PoPD < PoPD < PoPD/PANI.