scholarly journals Fabrication of Polypyrrole Nanoparticles Using Microemulsion Polymerization for Diferent Py/APS/SDS Molar Ratios

2016 ◽  
Vol 869 ◽  
pp. 391-395 ◽  
Author(s):  
Ricardo Hidalgo Santim ◽  
Hermes Adolfo de Aquino ◽  
José Antonio Malmonge
Keyword(s):  
Electrical Conductivity ◽  
Near Infrared ◽  
Sodium Dodecylsulfate ◽  
Ammonium Persulfate ◽  
Synthesis Temperature ◽  
Molar Ratio ◽  
Synthesis Conditions ◽  
Molar Ratios ◽  
Nanoparticle Shape ◽  
Polypyrrole Nanoparticles

Polypyrrole nanoparticles (PPy) were synthesized by the chemical oxidative microemulsion of pyrrole (Py) monomer using ammonium persulfate (APS) as an oxidant agent and sodium dodecylsulfate (SDS) as a surfactant at 28°C and 0°C. Different Py:APS:SDS molar ratios were used, and the properties of the resulting material were examined by four-probe DC electrical conductivity, ultraviolet-visible-near infrared (UV-vis-Nir), and Fourier-transform infrared (FTIR) spectroscopies as well as field-emission scanning electron microscopy (FESEM). UV-vis-Nir and FTIR spectra show the formation of a polaron band owing to the doping of PPy by SDS. The electrical conductivity and morphology of PPy nanoparticles depend on the synthesis conditions. Electrical conductivity of ~95.3×10-3 S/cm was achieved for PPy synthesized at 0°C. For the same Py:APS:SDS molar ratio, the nanoparticle shape changed from cylindrical to spherical upon simply lowering the synthesis temperature.

Self-doped N-4-sulfopropylaniline–3, 4-ethylenedioxythiophene copolymers

2016 ◽  
Vol 29 (8) ◽  
pp. 976-983 ◽  
Author(s):  
Isao Yamaguchi ◽  
Masaru Ito
Keyword(s):  
Electrical Conductivity ◽  
Electrochemical Oxidation ◽  
Visible Spectrum ◽  
Ammonium Persulfate ◽  
Feed Ratio ◽  
Molar Ratios ◽  
Monomer Feed ◽  
Monomer Feed Ratio

Polymerization of N-4-sulfopropylaniline with 3,4-ethylenedioxythiophene (EDOT) in several molar ratios using ammonium persulfate yielded copolymers (PPrSO3H) consisting of N-4-sulfopropylaminophenylene (unit A) and 3,4-ethylenedioxythiophene-2,5-diyl (unit B). The corresponding copolymers (PBu) consisting of N-butylaminophenylene (unit C) and unit B were synthesized by the reaction of N-butylaniline and EDOT. The content of units A, B, and C in the copolymers depended on the monomer feed ratio. The ultraviolet–visible spectrum of PPrSO3H exhibited absorption peaks at approximately 420 nm and above 850 nm assignable, respectively, to polaron and bipolaron bands. The copolymers were subjected to electrochemical oxidation, which was dependent on the contents of units A and C. The electrical conductivity of PPrSO3H was found to be higher than that of PBu.

Relationship between Dopant 5-Sulfosalicylic Acid and Conductivity of Ammonium Persulfate Oxidized Polypyrrole

2010 ◽  
Vol 663-665 ◽  
pp. 674-677
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai ◽  
Fu Fang Zhou ◽  
Chun Xu Pan
Keyword(s):  
Electrical Conductivity ◽  
Particle Size ◽  
Aqueous Medium ◽  
Ammonium Persulfate ◽  
Molar Ratio ◽  
Sulfosalicylic Acid ◽  
Maximum Value

The effects of dopant 5-sulfosalicylic acid on the conductivity of polypyrrole were investigated. Being nonhygroscopic, ammonium persulfate was used as the oxidant. Under the condition of fixed molar ratio of oxidant-to-monomer (0.375:1.00), a dozen of polypyrrole samples were made from chemical polymerizing the monomer pyrrole in aqueous medium by varying the dopant-to-monomer molar ratio. It was found that the dopant affected the conductivity and particle size of the synthesized polypyrrole. A maximum value for electrical conductivity of 5575 S/m was achieved when the molar ratio of dopant: oxidant: monomer is 2.25:0.375:1.00.

scholarly journals Aqueous synthesis of highly adsorptive copper–gallic acid metal–organic framework

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Badril Azhar ◽  
Artik Elisa Angkawijaya ◽  
Shella Permatasari Santoso ◽  
Chintya Gunarto ◽  
Aning Ayucitra ◽  
...  
Keyword(s):  
Gallic Acid ◽  
Metal Organic Framework ◽  
Synthesis Temperature ◽  
Molar Ratio ◽  
Aqueous Synthesis ◽  
Synthesis Conditions ◽  
Metal Organic ◽  
The Stability ◽  
Adsorption Desorption ◽  
Organic Framework

Abstract A greener route to synthesize mesoporous copper–gallic acid metal–organic framework (CuGA MOF) than the conventional method using harmful DMF solvent was proposed in this study. Various synthesis attempts were conducted by modifying the synthesis conditions to produce CuGA MOF with comparable physical properties to a reference material (DMF-synthesized CuGA NMOF). The independent variables investigated include the molar ratio of NaOH to GA (1.1 to 4.4) and the synthesis temperature (30, 60, 90 °C). It was found that proper NaOH addition was crucial for suppressing the generation of copper oxide while maximizing the formation of CuGA MOF. On the other hand, the reaction temperature mainly affected the stability and adsorption potential of CuGA MOF. Reacting Cu, GA, and NaOH at a molar ratio of 1:1:2.2 and a temperature of 90 °C, produced mesoporous MOF (CuGA 90–2.2) with a surface area of 198.22 m2/g, a pore diameter of 8.6 nm, and a thermal stability of 219 °C. This MOF exhibited an excellent adsorption capacity for the removal of methylene blue (124.64 mg/g) and congo red (344.54 mg/g). The potential usage of CuGA 90–2.2 as a reusable adsorbent was demonstrated by its high adsorption efficiency (> 90%) after 5 adsorption–desorption cycles.

scholarly journals The Use of a Biopolymer Conjugate for an Eco-Friendly One-Pot Synthesis of Palladium-Platinum Alloys

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1948 ◽  
Author(s):  
Daniele Silvestri ◽  
Stanisław Wacławek ◽  
Rohith K. Ramakrishnan ◽  
Abhilash Venkateshaiah ◽  
Kamil Krawczyk ◽  
...  
Keyword(s):  
Green Synthesis ◽  
Bimetallic Nanoparticles ◽  
Catalytic Reduction ◽  
Pt Nanoparticles ◽  
Attenuated Total Reflection ◽  
Molar Ratio ◽  
One Pot ◽  
Synthesis Conditions ◽  
Molar Ratios ◽  
Green Approach

Raising health and environmental concerns over the nanoparticles synthesized from hazardous chemicals have urged researchers to focus on safer, environmentally friendlier and cheaper alternatives as well as prompted the development of green synthesis. Apart from many advantages, green synthesis is often not selective enough (among other issues) to create shape-specific nanoparticle structures. Herein, we have used a biopolymer conjugate and Pd and Pt precursors to prepare sustainable bimetallic nanoparticles with various morphology types. The nanoparticles were synthesized by a novel green approach using a bio-conjugate of chitosan and polyhydroxybutyrate (Cs-PHB). The bio-conjugate plays the simultaneous roles of a reducing and a capping agent, which was confirmed by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and energy dispersive X-ray spectrometry (EDS) analysis, proving the presence of a Cs-PHB layer on the surface of the prepared nanoparticles. The EDS profile also revealed the elemental structure of these nanoparticles and confirmed the formation of a Pd/Pt alloy. TEM morphological analysis showed the formation of star-like, octahedron or decahedron Pd/Pt nanoparticles, depending on the synthesis conditions. The bimetallic Pd/Pt nanoparticles synthesized with various Pd/Pt molar ratios were successfully applied for the catalytic reduction of 4-nitrophenol to 4-aminophenol by borohydride. The calculated κc values (ratio of kapp to the concentration of the catalyst) revealed that the decahedron nanoparticles (size of 15 ± 4 nm), synthesized at the molar ratio of 2:1 (Pd/Pt), temperature of 130 °C, 10 g/L of Cs-PHB conjugate and time of 30 min, exhibited excellent catalytic activity compared to other bimetallic nanoparticles reported in the literature.

scholarly journals Influence of Zn/Fe Molar Ratio on Optical and Magnetic Properties of ZnO and ZnFe2O4Nanocrystal as Calcined Products of Layered Double Hydroxides

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Abdullah Ahmed Ali Ahmed ◽  
Zainal Abidin Talib ◽  
Mohd Zobir Hussein ◽  
Moayad Husein Flaifel ◽  
Naif Mohammed Al-Hada
Keyword(s):  
Magnetic Properties ◽  
Near Infrared ◽  
Mixed Oxides ◽  
Diffuse Reflectance Spectroscopy ◽  
Molar Ratio ◽  
Nanometer Scale ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Double Hydroxide ◽  
Double Hydroxides

The coprecipitation method has been used to synthesize layered double hydroxide (Zn-Fe-LDH) nanostructure at different Zn2+/Fe3+molar ratios. The structural properties of samples were studied using powder X-ray diffraction (PXRD). LDH samples were calcined at 600°C to produce mixed oxides (ZnO and ZnFe2O4). The crystallite size of mixed oxide was found in the nanometer scale (18.1 nm for ZnFe2O4and 43.3 nm for ZnO). The photocatalytic activity of the calcination products was investigated using ultraviolet-visible-near infrared (UV-VIS-NIR) diffuse reflectance spectroscopy. The magnetic properties of calcined LDHs were investigated using a vibrating sample magnetometer (VSM). The calcined samples showed a paramagnetic behavior for all Zn2+/Fe3+molar ratios. The effect of molar ratio on magnetic susceptibility of the calcined samples was also studied.

Synthesis of Polycarboxylate Superplasticizer with β-Cyclodextrins as Side Chain

2012 ◽  
Vol 455-456 ◽  
pp. 606-611
Author(s):  
Sheng Hua Lv ◽  
Rui Jun Gao ◽  
Di Li
Keyword(s):  
Maleic Anhydride ◽  
Ammonium Persulfate ◽  
Radical Copolymerization ◽  
Molar Ratio ◽  
Side Chain ◽  
Vinyl Monomers ◽  
Feeding Mode ◽  
Molar Ratios ◽  
Polycarboxylate Superplasticizer ◽  
Effect Of Feeding

A new polycarboxylate superplasticizer (NPC) was synthesized by radical copolymerization of maleic anhydride (MAH), sodium methylacryl sulfonate (MAS), allyl polyethylene glycols (APEG), and β-cyclodextrins grafted maleic anhydride (MAH-β-CD) using ammonium persulfate (APS) as initiator. The effect of feeding mode and molar ratio of monomers, contents of MAH-β-CD and reaction temperature on fluidity was discussed. The results show that the excellent properties of NPC were obtained when molar ratios of MAH, MAS, APEG and MAH-β-CD were 2.5: 0.5 : 1 : 0.1 in the presence of 1 mol% APS of all molar of vinyl monomers at 90 °C for 5 h. Meanwhile, the molecular structure was characterized by FTIR spectrum.

A Statistical Approach to the Effect of Sol-Gel Process Variables on the Physical Properties of Polymer [PLLA]-Silica Hybrid Materials for Use as Biomaterials

2002 ◽  
Vol 726 ◽  
Author(s):  
Carole C. Perry ◽  
David Eglin ◽  
Saad A.M. Ali ◽  
Sandra Downes
Keyword(s):  
Hybrid Materials ◽  
Sol Gel ◽  
Organic Polymer ◽  
Molar Ratio ◽  
Interpenetrating Networks ◽  
Silica Network ◽  
Scanning Calorimetry ◽  
Synthesis Conditions ◽  
Molar Ratios ◽  
Physical Form

AbstractHybrid poly(L-lactic acid)-silica materials for potential use in orthopaedic applications have been prepared by a sol-gel method using an experimental design approach to investigate the effect of synthesis variables separately and together on the physical form of the organic polymer. The five factors investigated were the molar ratios of tetraethyl orthosilicate (TEOS)/Poly(Llactic acid) (PLLA), Toluene/PLLA, EtOH/TEOS, Water/TEOS and HCl (catalyst)/TEOS. All other synthesis conditions were kept constant. X-Ray powder diffraction (Statton's graphical method) and differential scanning calorimetry were used to assess the extent of polymer crystallinity in the hybrid materials. In accordance with other studies, increasing the molar ratio of TEOS/PLLA lead to increasing incorporation of the organic polymer into the silica network. Increase of the toluene/PLLA molar ratio lead to an increase in the crystallinity of the polymer phase. As our studies investigated the effect of synthesis variables simultaneously it was possible to identify, for the first time, that interactions between specific reactants are important in the development of the two structural components of this hybrid system. The most important of these was the TEOS/PLLA*H2O/TEOS interaction that may indicate that silica species from hydrolysed TEOS interact with the PLLA phase possibly via hydrogen bonding and leads to the lowering of the crystalline order of the polymer The results from this study give useful information on the ability of the organic polymer and the silica phase to form interpenetrating networks, an important requirement for the generation of a potential hybrid polyester-silica biomaterial for orthopaedic applications.

Chemical synthesis of nanocomposites via in-situ polymerization of aniline and iodoaniline using exchanged montmorillonite

2020 ◽  
pp. 096739112095406
Author(s):  
Mokhtaria Abbas ◽  
Aicha Hachemaoui ◽  
Ahmed Yahiaoui ◽  
Abdel-Hamid I Mourad ◽  
Abdelkader Belfedal ◽  
...  
Keyword(s):  
In Situ Polymerization ◽  
Ammonium Persulfate ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Diffraction Peaks ◽  
Uv Visible ◽  
Xrd Patterns ◽  
Microscopy Techniques

The focus of this research is to synthesis different nanocomposites by in situ chemical polymerization. The nanocomposites were prepared by intercalating monomers such as aniline, iodoaniline or combination of aniline and 2-iodoaniline into modified montmorillonite clay. The syntheses were carried out using ammonium persulfate as oxidant with different molar ratios of oxidant to monomer. The resulting nanocomposites were investigated and confirmed by X-ray fluorescence spectroscopy, XRD, UV-visible, FTIR spectroscopy, cyclic voltammetry and transmission electron microscopy techniques. XRD patterns show that, the intensity of diffraction peaks for polymers/(M-Na) composites are lower than that for (M-Cu). This is attributed to the interaction of montmorillonite with polyaniline (PANI), polyiodoaniline (PIANI) and poly (ANI- co-2-IANI) molecular chains. The FTIR and UV-vis spectroscopic results also confirmed the presence of iodine in the nanocomposite. When looking at the yield of the process, highest yield is obtained for the poly (ANI- co-IANI) (80:20 molar ratio) and the lowest yield is for PANI/M-Na composite.

The Influence of Synthesis Conditions on the Structure of Mg-Al Layered Double Hydroxide

2015 ◽  
Vol 655 ◽  
pp. 267-270 ◽  
Author(s):  
Xiao Bo Wang ◽  
Zhi Min Bai ◽  
Zhi Yong He ◽  
Qi Fu Zhang ◽  
Fen Ling Qian
Keyword(s):  
Grain Size ◽  
Layered Double Hydroxide ◽  
Aging Temperature ◽  
Orthogonal Experiment ◽  
Great Influence ◽  
Chemical Precipitation ◽  
Synthesis Temperature ◽  
Molar Ratio ◽  
Synthesis Conditions ◽  
Double Hydroxide

In this paper, the influence of synthetic conditions (the molar ratio of Mg2+ and Al3+; the concentration of cationic; the aging temperature and time) on the grain size and crystallinity of Mg-Al layered double hydroxide (LDH) has been investigated systematically based on the orthogonal experiment. Mg-Al LDH was prepared using magnesite through chemical precipitation and hydrothermal methods. The samples were characterized by X-ray diffraction (XRD). The grain size which along a and c axis were calculated through Scherrer formula. The experimental results showed that the grain size along a axis increased with the rise of synthesis temperature, while the grain size along c axis reduced. It was also found that the aging temperature and time had a great influence on the crystallinity of Mg-Al LDH.

scholarly journals Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 346
Author(s):  
Sonam Goyal ◽  
Maizatul Shima Shaharun ◽  
Ganaga Suriya Jayabal ◽  
Chong Fai Kait ◽  
Bawadi Abdullah ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalyst Support ◽  
Oxidation Potential ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Optimum Parameters ◽  
Reduction Of Co2 ◽  
Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

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