It was seen that the density of PANI-silica composite is higher than that of the bulk polymer. Surface area measurements show that the PANI-silica composite has much higher than that of the bulk polymer.
Introduction
Conducting Polymers
The thermal motion of the ion nuclei decreases as the temperature decreases, resulting in a decrease in resistance or an increase in the degree of conductivity. The applicability of the term "doping" is the unifying theme that separates inherently conductive polymers from all others.
Polyaniline is the most prominent inherently conducting polymer
One of the important applications of the polymer composite as a conductive polymer as an electrode in rechargeable batteries. In such applications, the electrochemical reversibility of polymers acting as electrodes is used [12].
Composites
The polymer controls the chemical, thermal, and often electrical performance of the composites or matrix material, while the mechanical performance within the ultimate temperature performance of the polymer depends on the effectiveness of the reinforcement. With proper support and fiber reinforcement, the polymer or matrix material allows us to partially realize the inherent high strength and stiffness of the reinforcing fiber material.
Synthesis of PANI based composites
On the other hand, cyclic voltammetry involves sweeping the potential between potential boundaries at a known sweep rate. The polymerization process is carried out in a single room cell containing three electrodes namely working, counter and reference electrodes.
Optical Microscopy
The initial magnification of the objective eyepiece is used at the appropriate barrel length, the total magnification being equal to the product of the magnification of the objective and the eyepiece. In an optical microscope, the image is focused by changing the distance between the lenses.
Infra-red (IR) spectroscopy
The energy of most molecular vibrations corresponds to that infrared region of the electromagnetic spectrum. The techniques can be applied to many of the organic chromophore groups, as well as to many inorganic species.
Thermal Analysis
Thermo-gravimetric analysis (TGA) is a useful analytical technique to record weight loss of a test sample as a function of temperature which can then be used for an understanding of the chemical nature of the polymer. TGA thermograms are obtained by recording change in weight of the test sample as it is held at a constant high 11 .
Adsorption Study
If the solute is adsorbed more than the solvent, we get the usual positive adsorption, and the concentration of solute becomes less in the bulk of the solution. The species that is adsorbed is called adsorbate and the surface material is called adsorbent.
Silicon dioxide
Despite the large unit cell required to describe this structure, it is probably the simplest of the various crystallographic forms of SiO2. The general feature of the entire SiO2 structure is the same continuous network connected by SiO4 4 tetrahedra. Although the basic SiO4 tetrahedra are present in all SiO2 crystal structures, the arrangement of the connected tetrahedra varies [31].
General silica is a fresh powder, but colloidal silica called ludox is semi-liquid. Again, silica can be used as a catalyst for the decomposition of ammonium and can be used as a catalyst for the production of olefin polymers containing transition metal compounds and ionic compounds.
Metal Stearate
Ionic surfactants which contain a hydrophobic hydrocarbon group attached to one or several hydrophilic groups dissolve in a positively charged cation and a negatively charged anion in an aqueous solution. If the head is negatively charged to carry surface active properties, it is called an anionic surfactant, while a positively charged head is the carrier of surface active properties in cationic surfactants. Typically cationic surfactants are based on the nitrogen atom carrying the cationic charge such as amines and quaternary ammonium products.
Cationic surfactants include quaternary ammonium compounds, amines (primary, secondary, tertiary, diamines, polyamines, amine salts), imidazoline compounds and esterquats. Anionic surfactant is the commonly used type of surfactant for detergents, liquid cleaners and shampoos because of its excellent cleaning properties, which are especially effective in cleaning oily soils and suspending oily/clay soils. Anionic surfactant is used as an emulsifier in cosmetics, toothpaste, cream, shampoo and acrylic binder.
Anionic surfactants include alkyl benzene sulfonate, fatty acid salts, sodium lauryl sulfate, alkyl sulfate salts, sodium lauryl ether sulfate, alpha olefin sulfonates, phosphate esters, sulfosuccinates, alkyl phenol ether sulfates, and isothionates.
Sodium Dodecyl Sulfate
Ethylene Diamine Tetraacetic Acid
EDTA is used as industrial cleaning: complexation of Ca 2+ and Mg 2+ ions, binding of heavy metals. Pulp and paper industry: complexation of heavy metals during chlorine-free bleaching, stabilization of hydrogen peroxide.
Review of the literature
In the early 1980s, excitement ran high when several prototype devices based on conducting polymers, such as rechargeable batteries and rectifying p-n junction diodes [5 I], were announced. A dependence of the electrical strength on the thickness, surface area and volume of dieleric is shown for poly(propylene) film by S. It was shown that the function of electrical strength is not simply dependent on the volume as obtained from the theory of extreme values, but that an increase in volume by increasing the thickness of the dielectric is much more important than the same increase in dielectric volume caused by an increase in surface area.
Poly(dimethylsiloxane)/SiO2 and SiO2/TiO2 composites were successfully prepared using a sol-gel process by J. The hydrolysis and sol-gel transition reaction of the poly(dimethylsiloxane)/SiO2 system was studied by nuclear magnetic resonance , gel permeation chromatography, solvent extraction and shear modulus tests. In the past few years, considerable research has been devoted to the development of new processable forms of relatively air-stable conducting polymers such as Polypyrrole and PANI [63].
Cl, C104, NO3, mainly exhibits anion-exchange behavior due to the high mobility of these ions in the polymer matrix, but under certain conditions it was also found that cation exchange occurs in such systems.
Plan of the present work
Bunsell, "Fibres for Metallic composites the scientific Aspects and their relation to composite performances", Advanced in composite Materials Edited by P. Antonio, E.Desimoni, Cu desperate into poly(aniline) films as an amperometric sensor in alkaline solution of amino acids and polyhydric compounds, Anal. In Chemical Processing of Advanced Materials, ed. S. Maeda and S. P. Armes, "Preparation and Characterization of Novel Poly-pyrrole)/Siiica Colloidal Nanocomposites".
Watts, Synthesis and characterization of carboxylic acid-functionalized polypyrrole silica microparticles using a 3-substituted pyrrole comonomer, Langmuir. Hepel; "The electrocatalytic oxidation of methanol by finely dispersed platinum nanoparticles in poly(pyrrole) films", J.
Experimental
- Materials and Instruments
- Preparation of polyaniline-silica composites
- Preparation of polyaniline-Stearate composites
- Preparation of polyaniline-SDS composites
- Preparation of polyaniline - EDTA composites
- Analysis for silica content
- Infra-red spectroscopy
- UV-VIS spectral analysis
- Surface area
- Determination of reduces Mn2 -ion
- Determination of reduces As3 -ion
- References
The reaction mixture was stirred well for two hours and left overnight for completion of the reaction. The residue was cooled, the sides of the vessel were washed with water, and 2 cm3 of I-IF solution was carefully added back and the contents evaporated to dryness. Each sample was analyzed at least three times and the result reported is the average of the runs performed.
W2 = mass of the platinum crucible with lid plus sample (originally taken). W3= mass of the platinum crucible with lid plus sample (after ignition). IR spectra for the solid composites were obtained by mixing and grinding a small amount of the composite materials with dry and pure KBr. The pellet was then placed in the path of the IR beam in the spectrometer for measurements.
A dual-beam spectrophotometer (UV-160A Shimadzu, Japan) attached to a synchronized recorder was used for UV-VIS spectral analysis of various chemically prepared samples.
Resultand Discussion
Result and Discussion
General discussion on modified conducting polymer based composites
The chemical analyzes of these composites were performed on their silica and EDTA content, but these were not possible on SDS and stearate. The density values of the synthesized materials determined by pycnometry are also shown in Table 3. It is found that the density of the bulk polymer is smaller than that of polymer-silica composite materials.
On the other hand PANI-stearate, PANI-SDS and PANI-EDTA show densities lower than that of the bulk polymer. For the PANI-silica composite it can be considered that its surface composition is rich in silica compared to its bulk composition, i.e., the conductive polymer component is probably somewhat depleted from the particle surfaces. Due to the limited magnification of the optical microscope, free silicon could not be identified separately.
This result leads to the conclusion that our chemically synthesized composite materials containing counter anions such as stearate, SDS, and EDTA can be incorporated into the PANI matrix and have a large surface area.
PR spectral analysis of chemically synthesized samples
Thermal analyses of polymer based composites
Losses of carbon, hydrogen, and nitrogen show the same trend as bulk PANT, but the exothermic solder oxidation of carbon and hydrogen is stripper than bulk PANI. Only when the PANI-silica composites are heated above 650°C does the deep green color of the composites change to brilliant white grains or high density powder. The thermogram (Fig.3.3.4) for PANI stearate shows the similar trends for loss of carbon and hydrogen.
In addition, it also shows three endothermic processes at nearly around 340°C, 370°C, and 470°C, which indicate the formation of Na2O, NO, and Na2O2, respectively. Here it should be noted that we used sodium stearate to produce PAN! stearate composite. In addition to them, almost the endothermic solder shows between 400°C -450°C, which can be attributed to the formation of SO2.
Thermograms of PAN!- EDTA show a sharp endothermic process at 250°C which corresponds to the loss of crystalline water present in the system.
Adsorption study
The concentration, decay is very sharp for the Mn2 in the case of PANI-silica system Fig. Curve -b) compared to that of bulk PANI and other composite materials. Since Mn2 is in the cationic form, its adsorption on the PANI silica is quite likely. The degree of adsorption of Mn2 on PANI silica appears to be four times higher than that for bulk PANI.
This result seems to be consistent with a previous study on nitrogen adsorption on PP and PANI-silica matrix [41]. Cationic charge present on As3 can play an important role in the amount of adsorbed particles. At first glance it can be assumed that PANI-EDTA, PANI-stearate and PANI-SDS can act as ion exchangers for the Mn2 ions.
PANI-stearate and PANI-SDS can similarly adsorb As3 from aqueous solution.
Co n clusion
Conclusion
