Fly ash and multiwalled carbon nanotubes (MWCNT) reinforced multiphase polyurethane (PU) composit... more Fly ash and multiwalled carbon nanotubes (MWCNT) reinforced multiphase polyurethane (PU) composite sheets have been fabricated by using a solution casting technique. Utilization of fly ash was the prime objective in order to reduce environmental pollution and to enhance the shielding properties of PU polymer. Our study proves that fly ash particles with MWCNTs in a PU matrix leads to novel hybrid high performance electromagnetic shielding interference material. Scanning electron microscopy confirms the existence of fly ash particles along with MWCNTs in a PU matrix. This multiphase composite shows total shielding effectiveness of 35.8 dB (>99.99% attenuation) in the Ku-band (12.4-18 GHz) frequency range. This is attributed to high dielectric losses of reinforcement present in the polymers matrix. The Nicolson-Ross-Weir algorithm has been applied to calculate the electromagnetic attributes and dielectric parameters of the PU samples by using scattering parameters (S 11 , S 22 , S 12 , S 21). The synthesized multiphase composites were further characterized by using x-ray diffraction, Fourier transform infrared spectroscopy, and thermo gravimetric analysis.
Highly Durable and Novel Anticorrosive Coating Based on Epoxy Reinforced with Poly(Aniline-co-Pentafluoroaniline)/SiO 2 Composite
The paper presents the development of high strength anticorrosive coating based on epoxy formulat... more The paper presents the development of high strength anticorrosive coating based on epoxy formulated with poly(aniline-co-2,3,4,5,6 pentafluoro aniline)/SiO2 composite. The composites display outstanding barrier properties against corrosive ions. SiO2 particles were found to significantly improve the microstructure of the coating matrix and thus enhanced both the anticorrosive performance and mechanical property of the epoxy coating. Electrochemical characterization was carried out in 3.5 wt% NaCl which show a remarkable improvement in the corrosion resistance of epoxy coating with addition of copolymer composites. The high pore resistance indicates the slow migration of ions into the metal and coating interface. Remarkable reduction of corrosion current density from 84.0 µA/cm2 in epoxy coating to 2.0 µA/cm2 in epoxy with copolymer/SiO2 composite coating was observed. Salt spray test of coated mild steel was carried out in 5.0 wt.% NaCl solution for 120 days as per ASTM B117 method....
Fly ash and multiwalled carbon nanotubes (MWCNT) reinforced multiphase polyurethane (PU) composit... more Fly ash and multiwalled carbon nanotubes (MWCNT) reinforced multiphase polyurethane (PU) composite sheets have been fabricated by using a solution casting technique. Utilization of fly ash was the prime objective in order to reduce environmental pollution and to enhance the shielding properties of PU polymer. Our study proves that fly ash particles with MWCNTs in a PU matrix leads to novel hybrid high performance electromagnetic shielding interference material. Scanning electron microscopy confirms the existence of fly ash particles along with MWCNTs in a PU matrix. This multiphase composite shows total shielding effectiveness of 35.8 dB (>99.99% attenuation) in the Ku-band (12.4-18 GHz) frequency range. This is attributed to high dielectric losses of reinforcement present in the polymers matrix. The Nicolson-Ross-Weir algorithm has been applied to calculate the electromagnetic attributes and dielectric parameters of the PU samples by using scattering parameters (S 11 , S 22 , S 12 , S 21). The synthesized multiphase composites were further characterized by using x-ray diffraction, Fourier transform infrared spectroscopy, and thermo gravimetric analysis.
An attempt has been made to design lightweight polypyrrole/carbon fibers and polypyrrole/carbon f... more An attempt has been made to design lightweight polypyrrole/carbon fibers and polypyrrole/carbon fibers/ferrofluid (Fe 3 O 4 particles) composite sheets using novolac resin via compression molding for electromagnetic shielding applications. The optimized formulation has been achieved to get an excellent combination of thermal, mechanical, and electrical properties of the composite sheet. Structural and morphological studies were carried out by x-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Polypyrrole/carbon fibers composite sheets shows maximum flexural strength and a flexural modulus of 62.4 ± 1 MPa and 0.60 ± 0.02 GPa, respectively, with total shielding effectiveness of 22.8 dB in the Ku-band (12.4-18 GHz) but when ferrofluid is added to the polypyrrole/carbon fibers composite system, flexural strength increases to 92.3 ± 1 MPa and the same trend has been observed for flexural modulus with a value of 0.65 ± 0.04 GPa. This multiphase lightweight polypyrrole composite sheet having 34 vol.% of carbon fibers and 4 vol.% of Fe 3 O 4 nanoparticles offers total shielding effectiveness of 31.9 dB (>99.99% attenuation) in the Ku-band (12.4-18 GHz) frequency range with a thickness of $1.25 mm. This is accredited to high dielectric losses and magnetic losses in conducting composite sheets. The observed results suggest that lightweight compression molded polypyrrole composite sheets could be a potential commercial alternative for electromagnetic shielding applications.
Sandwich composites of polyurethane reinforced with poly(3,4-ethylene dioxythiophene)-coated multiwalled carbon nanotubes with exceptional electromagnetic interference shielding properties
RSC Advances, 2015
PEDOT/MWCNT/PU composite films were designed, which show a shielding effectiveness of ∼45 dB in t... more PEDOT/MWCNT/PU composite films were designed, which show a shielding effectiveness of ∼45 dB in the Ku-band and a static decay time of 0.2 s which can find applications for the control of EM pollution also as an ESD material for the encapsulation of electronic equipments.
A series of fluorene based random copolymers incorporating two acceptor units-4,7-dithienyl-2, 1,... more A series of fluorene based random copolymers incorporating two acceptor units-4,7-dithienyl-2, 1,3-benzothiadiazole and N-heterocyclic moieties (2,1,3-benzothiadiazole, [2,3-b]phenanthrenequinoxaline, [2,3-b]-acenaphthenequinoxaline) have been synthesized by Suzuki polycondensation method. The synthesized polymer films exhibit strong absorption in the range from 300 nm to 700 nm with good solubility and thermal stability. The optical band gap of the synthesized copolymers are in the range of 1.86-1.90 eV. The HOMO energy levels of the polymers calculated from cyclic voltammetry measurements have been found to be in the range from −5.45 to −5.70 eV. Using these new electron donor copolymers, solar cells were fabricated and highest efficiency was obtained with PFQx(phen)DTBT as an electron donor and PC 71 BM as an electron acceptor. In fact with PFQx(phen)DTBT:PC 71 BM in the ratio of 1:4, a power conversion efficiency (PCE) ∼0.47% has been achieved with open-circuit voltage (V oc) 0.59 V, short circuit current density (J sc) ∼2.49 mA/cm 2 and fill factor (FF) ∼ 32% under the illumination of AM1.5G, 100 mW cm −2 .
International Journal of Research in Engineering and Technology, 2016
The paper reports the corrosion inhibition performance of highly soluble conducting copolymer bas... more The paper reports the corrosion inhibition performance of highly soluble conducting copolymer based on Poly(o-Toluidine-co-2-Amino-5-Naphthol-7-Sulphonic Acid). The copolymer was synthesized by in situ chemical oxidative polymerization method by taking different molar concentration of comonomers. Characterization of synthesized copolymer was carried out by using FTIR, TGA and SEM measurement. The corrosion inhibition behaviour of the copolymer in 1.0 M HCl has been evaluated using Tafel Extrapolation method, electrochemical impedance spectroscopy (EIS) and weight loss measurements. The results showed that the copolymer consists of higher concentration of naphthyl amine comonomer exhibited the significant shifting in the corrosion potential and greater charge transfer resistance in highly aggressive medium such as 1.0 M HCl. Maximum corrosion inhibition efficiency up to 95 % was obtained at 200 ppm concentration of the inhibitor. Moreover, the copolymer showed the larger degree of surface coverage onto the iron surface exhibits least corrosion rate, indicating the better protection of the iron in highly acidic medium.
The paper presents the development of high strength anticorrosive coating based on epoxy formulat... more The paper presents the development of high strength anticorrosive coating based on epoxy formulated with poly(aniline-co-2,3,4,5,6 pentafluoro aniline)/SiO 2 composite. The composites display outstanding barrier properties against corrosive ions. SiO 2 particles were found to significantly improve the microstructure of the coating matrix and thus enhanced both the anticorrosive performance and mechanical property of the epoxy coating. Electrochemical characterization was carried out in 3.5 wt% NaCl which show a remarkable improvement in the corrosion resistance of epoxy coating with addition of copolymer composites. The high pore resistance indicates the slow migration of ions into the metal and coating interface. Remarkable reduction of corrosion current density from 84.0 µA/cm 2 in epoxy coating to 2.0 µA/cm 2 in epoxy with copolymer/SiO 2 composite coating was observed. Salt spray test of coated mild steel was carried out in 5.0 wt.% NaCl solution for 120 days as per ASTM B117 method. Electrochemical studies and salt spray test indicate the superior anticorrosive performance offered by the co-polymer composite under accelerated test conditions. Mechanical testing such as bend test, Taber abrasion resistance and cross cut adhesion test of epoxy formulated copolymer composite were carried out to evaluate the durability and adhesion performance of coating on the metal surface. The results show that the coating based on copolymer/SiO 2 composites has improved corrosion resistance performance as well as mechanical properties more than several times as compared to epoxy coating. Better mechanical and barrier properties of the epoxy based copolymer composite were able to make the coating highly durable and anticorrosive in aggressive environment. Moreover, the significantly improved corrosion protection and mechanical strength is attributed to the synergistic effect of SiO 2 particles and pentafluoro aniline in copolymer chain. We expect that the present concept opens new ways to prepare conducting polymer composite based epoxy coating for anticorrosion and other functional purposes.
The effect of the concentrations of the oxidizing agent (sodium persulphate) on the properties of... more The effect of the concentrations of the oxidizing agent (sodium persulphate) on the properties of poly (m-aminobenzene sulfonic acid-co-aniline) p(m-ABSA-co-Ani) co-polymer has been investigated. The prepared samples were confirmed by Fourier transformation infrared spectroscopy and further, characterized by electron paramagnetic resonance (EPR), UV-Vis spectroscopic techniques and tested for temperature dependent stability by thermogravimetric analyses. The room-temperature conductivity measurements have been performed on all the p(m-ABSA-co Ani) co-polymers samples and found a maximum value of conductivity of ~ 6.5 × 10-2 S/cm at 168 mM concentration of oxidizing agent. The EPR studies have been shown that the variation of line width of EPR signals with oxidizing agent concentration and found a close relation with electrical conductivity. The prepared co-polymer samples are thermally stable up to 600 o C detected by TGA analysis. The synthesized co-polymer materials show around 75...
The effect of the concentrations of the oxidizing agent (sodium persulphate) on the properties of... more The effect of the concentrations of the oxidizing agent (sodium persulphate) on the properties of poly (m-aminobenzene sulfonic acid -co- aniline) p(m-ABSA-co-Ani) co-polymer has been investigated. The prepared samples were confirmed by Fourier transformation infrared spectroscopy and further , characterized by electron paramagnetic resonance (EPR), UV-Vis spectroscopic techniques and tested for temperature dependent stability by thermogravimetric analyses. The room-temperature conductivity measurements have been performed on all the p(m-ABSA-co Ani) co-polymers samples and found a maximum value of conductivity of ~ 6.5 × 10 -2 S/cm at 168 mM concentration of oxidizing agent. The EPR studies have been shown that the variation of line width of EPR signals withoxidizing agent concentration and found a close relation with electrical conductivity. The prepared co-polymer samples are thermally stable up to 600 o C detected by TGA analysis. The synthesized co-polymer materials show around...
The paper reports the preparation of thin sheets of expanded graphite decorated with -Fe 2 O 3 an... more The paper reports the preparation of thin sheets of expanded graphite decorated with -Fe 2 O 3 and SiO 2 by compression molding. Different formulations have been prepared to study the effect of dielectric and magnetic constituent on the electrical, magnetic and dielectric properties of multiphase composite. One of the formulations shows unprecedented microwave shielding response with absorption dominated shielding effectiveness value of 55.40 dB which strongly depends on dielectric losses and magnetic losses. The results show that the dielectric loss of the composites can be attributed to natural resonance, electron polarization relaxation, interfacial polarization and the unique layered nanostructures etc.; whereas eddy current effect mainly causes the magnetic loss. Since observed attenuation is greater than the recommended limit (30 to 40 dB) of commercial application, therefore, these are potentially applied for absorbing mobile signal interference in daily life.
The paper reports the corrosion inhibition performance of highly soluble conducting copolymer bas... more The paper reports the corrosion inhibition performance of highly soluble conducting copolymer based on Poly(o-Toluidine-co-2-Amino-5-Naphthol-7-Sulphonic Acid). The copolymer was synthesized by in situ chemical oxidative polymerization method by taking different molar concentration of comonomers. Characterization of synthesized copolymer was carried out by using FTIR, TGA and SEM measurement. The corrosion inhibition behaviour of the copolymer in 1.0 M HCl has been evaluated using Tafel Extrapolation method, electrochemical impedance spectroscopy (EIS) and weight loss measurements. The results showed that the copolymer consists of higher concentration of naphthyl amine comonomer exhibited the significant shifting in the corrosion potential and greater charge transfer resistance in highly aggressive medium such as 1.0 M HCl. Maximum corrosion inhibition efficiency up to 95 % was obtained at 200 ppm concentration of the inhibitor. Moreover, the copolymer showed the larger degree of su...
Conducting polymer nanocomposites of polyphenyl amine with barium ferrite nanoparticles ͑50-70 nm... more Conducting polymer nanocomposites of polyphenyl amine with barium ferrite nanoparticles ͑50-70 nm͒ have been synthesized via emulsion polymerization. The complex permittivity, permeability, and microwave absorption properties of the composite were studied in the 12.4-18 GHz ͑Ku band͒ frequency range. The composite has shown high shielding effectiveness due to absorption ͑SE A ͒ of 28.9 dB ͑ϳ99.9% ͒, which strongly depends on dielectric loss, magnetic permeability, and volume fraction of barium ferrite nanoparticles. The high value of SE A suggests that these composites can be used as a promising radar absorbing materials.
A novel study on conducting polymers based composites involving hybrid carbon nanostructure assem... more A novel study on conducting polymers based composites involving hybrid carbon nanostructure assemblage of graphene, amine functionalized multiwalled carbon nanotubes and poly(aniline-co-pyrrole) has been done. The composites were synthesized by oxidative polymerization of 1:1 mixture of aniline and pyrrole monomer with ammonium per sulphate and ferric chloride oxidants. UV-vis Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy were used to identify the chemical structure of the obtained composites. Thermal studies indicate that the composites are stable in comparison to poly (aniline-co-pyrrole) alone showing that the hybrid carbon assemblage contributes towards thermal stability in the composites. Crystalline properties of the composites were investigated by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was used to characterize the surface morphology of the composites. The specific capacitance of the composites was characterized by cyclic voltammogram (CV). The capacitive studies reveal that the composite has synergistic effect and highest specific capacitance of 337.35F/g at scan rate of 10mV/sec and 193.06F/g at scan rate of 50 mV/sec was obtained for the composite having thinnest layer of co-polymer over hybrid carbon assemblage i.e., 02-PANI-co-PPY-C.
Fly ash and multiwalled carbon nanotubes (MWCNT) reinforced multiphase polyurethane (PU) composit... more Fly ash and multiwalled carbon nanotubes (MWCNT) reinforced multiphase polyurethane (PU) composite sheets have been fabricated by using a solution casting technique. Utilization of fly ash was the prime objective in order to reduce environmental pollution and to enhance the shielding properties of PU polymer. Our study proves that fly ash particles with MWCNTs in a PU matrix leads to novel hybrid high performance electromagnetic shielding interference material. Scanning electron microscopy confirms the existence of fly ash particles along with MWCNTs in a PU matrix. This multiphase composite shows total shielding effectiveness of 35.8 dB (>99.99% attenuation) in the Ku-band (12.4-18 GHz) frequency range. This is attributed to high dielectric losses of reinforcement present in the polymers matrix. The Nicolson-Ross-Weir algorithm has been applied to calculate the electromagnetic attributes and dielectric parameters of the PU samples by using scattering parameters (S 11 , S 22 , S 12 , S 21). The synthesized multiphase composites were further characterized by using x-ray diffraction, Fourier transform infrared spectroscopy, and thermo gravimetric analysis.
Highly Durable and Novel Anticorrosive Coating Based on Epoxy Reinforced with Poly(Aniline-co-Pentafluoroaniline)/SiO 2 Composite
The paper presents the development of high strength anticorrosive coating based on epoxy formulat... more The paper presents the development of high strength anticorrosive coating based on epoxy formulated with poly(aniline-co-2,3,4,5,6 pentafluoro aniline)/SiO2 composite. The composites display outstanding barrier properties against corrosive ions. SiO2 particles were found to significantly improve the microstructure of the coating matrix and thus enhanced both the anticorrosive performance and mechanical property of the epoxy coating. Electrochemical characterization was carried out in 3.5 wt% NaCl which show a remarkable improvement in the corrosion resistance of epoxy coating with addition of copolymer composites. The high pore resistance indicates the slow migration of ions into the metal and coating interface. Remarkable reduction of corrosion current density from 84.0 µA/cm2 in epoxy coating to 2.0 µA/cm2 in epoxy with copolymer/SiO2 composite coating was observed. Salt spray test of coated mild steel was carried out in 5.0 wt.% NaCl solution for 120 days as per ASTM B117 method....
Fly ash and multiwalled carbon nanotubes (MWCNT) reinforced multiphase polyurethane (PU) composit... more Fly ash and multiwalled carbon nanotubes (MWCNT) reinforced multiphase polyurethane (PU) composite sheets have been fabricated by using a solution casting technique. Utilization of fly ash was the prime objective in order to reduce environmental pollution and to enhance the shielding properties of PU polymer. Our study proves that fly ash particles with MWCNTs in a PU matrix leads to novel hybrid high performance electromagnetic shielding interference material. Scanning electron microscopy confirms the existence of fly ash particles along with MWCNTs in a PU matrix. This multiphase composite shows total shielding effectiveness of 35.8 dB (>99.99% attenuation) in the Ku-band (12.4-18 GHz) frequency range. This is attributed to high dielectric losses of reinforcement present in the polymers matrix. The Nicolson-Ross-Weir algorithm has been applied to calculate the electromagnetic attributes and dielectric parameters of the PU samples by using scattering parameters (S 11 , S 22 , S 12 , S 21). The synthesized multiphase composites were further characterized by using x-ray diffraction, Fourier transform infrared spectroscopy, and thermo gravimetric analysis.
An attempt has been made to design lightweight polypyrrole/carbon fibers and polypyrrole/carbon f... more An attempt has been made to design lightweight polypyrrole/carbon fibers and polypyrrole/carbon fibers/ferrofluid (Fe 3 O 4 particles) composite sheets using novolac resin via compression molding for electromagnetic shielding applications. The optimized formulation has been achieved to get an excellent combination of thermal, mechanical, and electrical properties of the composite sheet. Structural and morphological studies were carried out by x-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Polypyrrole/carbon fibers composite sheets shows maximum flexural strength and a flexural modulus of 62.4 ± 1 MPa and 0.60 ± 0.02 GPa, respectively, with total shielding effectiveness of 22.8 dB in the Ku-band (12.4-18 GHz) but when ferrofluid is added to the polypyrrole/carbon fibers composite system, flexural strength increases to 92.3 ± 1 MPa and the same trend has been observed for flexural modulus with a value of 0.65 ± 0.04 GPa. This multiphase lightweight polypyrrole composite sheet having 34 vol.% of carbon fibers and 4 vol.% of Fe 3 O 4 nanoparticles offers total shielding effectiveness of 31.9 dB (>99.99% attenuation) in the Ku-band (12.4-18 GHz) frequency range with a thickness of $1.25 mm. This is accredited to high dielectric losses and magnetic losses in conducting composite sheets. The observed results suggest that lightweight compression molded polypyrrole composite sheets could be a potential commercial alternative for electromagnetic shielding applications.
Sandwich composites of polyurethane reinforced with poly(3,4-ethylene dioxythiophene)-coated multiwalled carbon nanotubes with exceptional electromagnetic interference shielding properties
RSC Advances, 2015
PEDOT/MWCNT/PU composite films were designed, which show a shielding effectiveness of ∼45 dB in t... more PEDOT/MWCNT/PU composite films were designed, which show a shielding effectiveness of ∼45 dB in the Ku-band and a static decay time of 0.2 s which can find applications for the control of EM pollution also as an ESD material for the encapsulation of electronic equipments.
A series of fluorene based random copolymers incorporating two acceptor units-4,7-dithienyl-2, 1,... more A series of fluorene based random copolymers incorporating two acceptor units-4,7-dithienyl-2, 1,3-benzothiadiazole and N-heterocyclic moieties (2,1,3-benzothiadiazole, [2,3-b]phenanthrenequinoxaline, [2,3-b]-acenaphthenequinoxaline) have been synthesized by Suzuki polycondensation method. The synthesized polymer films exhibit strong absorption in the range from 300 nm to 700 nm with good solubility and thermal stability. The optical band gap of the synthesized copolymers are in the range of 1.86-1.90 eV. The HOMO energy levels of the polymers calculated from cyclic voltammetry measurements have been found to be in the range from −5.45 to −5.70 eV. Using these new electron donor copolymers, solar cells were fabricated and highest efficiency was obtained with PFQx(phen)DTBT as an electron donor and PC 71 BM as an electron acceptor. In fact with PFQx(phen)DTBT:PC 71 BM in the ratio of 1:4, a power conversion efficiency (PCE) ∼0.47% has been achieved with open-circuit voltage (V oc) 0.59 V, short circuit current density (J sc) ∼2.49 mA/cm 2 and fill factor (FF) ∼ 32% under the illumination of AM1.5G, 100 mW cm −2 .
International Journal of Research in Engineering and Technology, 2016
The paper reports the corrosion inhibition performance of highly soluble conducting copolymer bas... more The paper reports the corrosion inhibition performance of highly soluble conducting copolymer based on Poly(o-Toluidine-co-2-Amino-5-Naphthol-7-Sulphonic Acid). The copolymer was synthesized by in situ chemical oxidative polymerization method by taking different molar concentration of comonomers. Characterization of synthesized copolymer was carried out by using FTIR, TGA and SEM measurement. The corrosion inhibition behaviour of the copolymer in 1.0 M HCl has been evaluated using Tafel Extrapolation method, electrochemical impedance spectroscopy (EIS) and weight loss measurements. The results showed that the copolymer consists of higher concentration of naphthyl amine comonomer exhibited the significant shifting in the corrosion potential and greater charge transfer resistance in highly aggressive medium such as 1.0 M HCl. Maximum corrosion inhibition efficiency up to 95 % was obtained at 200 ppm concentration of the inhibitor. Moreover, the copolymer showed the larger degree of surface coverage onto the iron surface exhibits least corrosion rate, indicating the better protection of the iron in highly acidic medium.
The paper presents the development of high strength anticorrosive coating based on epoxy formulat... more The paper presents the development of high strength anticorrosive coating based on epoxy formulated with poly(aniline-co-2,3,4,5,6 pentafluoro aniline)/SiO 2 composite. The composites display outstanding barrier properties against corrosive ions. SiO 2 particles were found to significantly improve the microstructure of the coating matrix and thus enhanced both the anticorrosive performance and mechanical property of the epoxy coating. Electrochemical characterization was carried out in 3.5 wt% NaCl which show a remarkable improvement in the corrosion resistance of epoxy coating with addition of copolymer composites. The high pore resistance indicates the slow migration of ions into the metal and coating interface. Remarkable reduction of corrosion current density from 84.0 µA/cm 2 in epoxy coating to 2.0 µA/cm 2 in epoxy with copolymer/SiO 2 composite coating was observed. Salt spray test of coated mild steel was carried out in 5.0 wt.% NaCl solution for 120 days as per ASTM B117 method. Electrochemical studies and salt spray test indicate the superior anticorrosive performance offered by the co-polymer composite under accelerated test conditions. Mechanical testing such as bend test, Taber abrasion resistance and cross cut adhesion test of epoxy formulated copolymer composite were carried out to evaluate the durability and adhesion performance of coating on the metal surface. The results show that the coating based on copolymer/SiO 2 composites has improved corrosion resistance performance as well as mechanical properties more than several times as compared to epoxy coating. Better mechanical and barrier properties of the epoxy based copolymer composite were able to make the coating highly durable and anticorrosive in aggressive environment. Moreover, the significantly improved corrosion protection and mechanical strength is attributed to the synergistic effect of SiO 2 particles and pentafluoro aniline in copolymer chain. We expect that the present concept opens new ways to prepare conducting polymer composite based epoxy coating for anticorrosion and other functional purposes.
The effect of the concentrations of the oxidizing agent (sodium persulphate) on the properties of... more The effect of the concentrations of the oxidizing agent (sodium persulphate) on the properties of poly (m-aminobenzene sulfonic acid-co-aniline) p(m-ABSA-co-Ani) co-polymer has been investigated. The prepared samples were confirmed by Fourier transformation infrared spectroscopy and further, characterized by electron paramagnetic resonance (EPR), UV-Vis spectroscopic techniques and tested for temperature dependent stability by thermogravimetric analyses. The room-temperature conductivity measurements have been performed on all the p(m-ABSA-co Ani) co-polymers samples and found a maximum value of conductivity of ~ 6.5 × 10-2 S/cm at 168 mM concentration of oxidizing agent. The EPR studies have been shown that the variation of line width of EPR signals with oxidizing agent concentration and found a close relation with electrical conductivity. The prepared co-polymer samples are thermally stable up to 600 o C detected by TGA analysis. The synthesized co-polymer materials show around 75...
The effect of the concentrations of the oxidizing agent (sodium persulphate) on the properties of... more The effect of the concentrations of the oxidizing agent (sodium persulphate) on the properties of poly (m-aminobenzene sulfonic acid -co- aniline) p(m-ABSA-co-Ani) co-polymer has been investigated. The prepared samples were confirmed by Fourier transformation infrared spectroscopy and further , characterized by electron paramagnetic resonance (EPR), UV-Vis spectroscopic techniques and tested for temperature dependent stability by thermogravimetric analyses. The room-temperature conductivity measurements have been performed on all the p(m-ABSA-co Ani) co-polymers samples and found a maximum value of conductivity of ~ 6.5 × 10 -2 S/cm at 168 mM concentration of oxidizing agent. The EPR studies have been shown that the variation of line width of EPR signals withoxidizing agent concentration and found a close relation with electrical conductivity. The prepared co-polymer samples are thermally stable up to 600 o C detected by TGA analysis. The synthesized co-polymer materials show around...
The paper reports the preparation of thin sheets of expanded graphite decorated with -Fe 2 O 3 an... more The paper reports the preparation of thin sheets of expanded graphite decorated with -Fe 2 O 3 and SiO 2 by compression molding. Different formulations have been prepared to study the effect of dielectric and magnetic constituent on the electrical, magnetic and dielectric properties of multiphase composite. One of the formulations shows unprecedented microwave shielding response with absorption dominated shielding effectiveness value of 55.40 dB which strongly depends on dielectric losses and magnetic losses. The results show that the dielectric loss of the composites can be attributed to natural resonance, electron polarization relaxation, interfacial polarization and the unique layered nanostructures etc.; whereas eddy current effect mainly causes the magnetic loss. Since observed attenuation is greater than the recommended limit (30 to 40 dB) of commercial application, therefore, these are potentially applied for absorbing mobile signal interference in daily life.
The paper reports the corrosion inhibition performance of highly soluble conducting copolymer bas... more The paper reports the corrosion inhibition performance of highly soluble conducting copolymer based on Poly(o-Toluidine-co-2-Amino-5-Naphthol-7-Sulphonic Acid). The copolymer was synthesized by in situ chemical oxidative polymerization method by taking different molar concentration of comonomers. Characterization of synthesized copolymer was carried out by using FTIR, TGA and SEM measurement. The corrosion inhibition behaviour of the copolymer in 1.0 M HCl has been evaluated using Tafel Extrapolation method, electrochemical impedance spectroscopy (EIS) and weight loss measurements. The results showed that the copolymer consists of higher concentration of naphthyl amine comonomer exhibited the significant shifting in the corrosion potential and greater charge transfer resistance in highly aggressive medium such as 1.0 M HCl. Maximum corrosion inhibition efficiency up to 95 % was obtained at 200 ppm concentration of the inhibitor. Moreover, the copolymer showed the larger degree of su...
Conducting polymer nanocomposites of polyphenyl amine with barium ferrite nanoparticles ͑50-70 nm... more Conducting polymer nanocomposites of polyphenyl amine with barium ferrite nanoparticles ͑50-70 nm͒ have been synthesized via emulsion polymerization. The complex permittivity, permeability, and microwave absorption properties of the composite were studied in the 12.4-18 GHz ͑Ku band͒ frequency range. The composite has shown high shielding effectiveness due to absorption ͑SE A ͒ of 28.9 dB ͑ϳ99.9% ͒, which strongly depends on dielectric loss, magnetic permeability, and volume fraction of barium ferrite nanoparticles. The high value of SE A suggests that these composites can be used as a promising radar absorbing materials.
A novel study on conducting polymers based composites involving hybrid carbon nanostructure assem... more A novel study on conducting polymers based composites involving hybrid carbon nanostructure assemblage of graphene, amine functionalized multiwalled carbon nanotubes and poly(aniline-co-pyrrole) has been done. The composites were synthesized by oxidative polymerization of 1:1 mixture of aniline and pyrrole monomer with ammonium per sulphate and ferric chloride oxidants. UV-vis Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy were used to identify the chemical structure of the obtained composites. Thermal studies indicate that the composites are stable in comparison to poly (aniline-co-pyrrole) alone showing that the hybrid carbon assemblage contributes towards thermal stability in the composites. Crystalline properties of the composites were investigated by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was used to characterize the surface morphology of the composites. The specific capacitance of the composites was characterized by cyclic voltammogram (CV). The capacitive studies reveal that the composite has synergistic effect and highest specific capacitance of 337.35F/g at scan rate of 10mV/sec and 193.06F/g at scan rate of 50 mV/sec was obtained for the composite having thinnest layer of co-polymer over hybrid carbon assemblage i.e., 02-PANI-co-PPY-C.
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Papers by Sundeep Dhawan