Lingam Ravikumar | Bharathiar University, Coimbatore, Tamilnadu, INDIA (original) (raw)
Papers by Lingam Ravikumar
after in opto-electronic field. One such attempt was to synthesize poly(azomethine ester)s with a... more after in opto-electronic field. One such attempt was to synthesize poly(azomethine ester)s with a pendent group. In this study, the newly synthesized diacid monomer benzalaniline 3’-4’dimethoxy terepthalic acid was condensed with two diol monomers to get the polymers with pendent benzylidene group. The diacid monomer was characterized by UV, IR, NMR and CHNS analysis. The polymers were characterized by IR, TGA, and for liquid crystalline property. Polymer-I showed the highest thermal stability upto 335°C. Polymer-II exhibited liquid crystalline nature along with good solubi- lity and thermal stability.
A series of novel ladder-type poly(azomethine amide)s (PAMs) were prepared from new azomethine co... more A series of novel ladder-type poly(azomethine amide)s (PAMs) were prepared from new azomethine containing
carboxylic acid monomer (TCA) with simple aromatic diamines and aromatic diamines with thiourea groups
(TDAs) by means of phosphorylation polycondensation reaction. Molecular weights of the polyamides were
evaluated viscometrically, and the inherent viscosities were in the range of 0.31 - 0.58 g/dl. These ladder-type
polymers were not freely soluble in common organic solvents. Structure of monomers and polymers were confirmed
using FT-IR, 1H-NMR and 13C-NMR spectroscopic analysis. Removal of Cu2+ and Cd2+ from aqueous
solutions by adsorption onto the polyamides was investigated. The effect of pH, initial metal ion concentrations
and contact time were studied in batch experiments. The polyamides were found to be highly effective adsorbents
for the removal of Cu2+ and Cd2+ metal ions from aqueous solutions. In a mixture of metal ions, the
selectivity order was found to be Pb(II) > Cu(II) > Cr(IV) > Cd(II).
Desalination, 2011
The removal of Pb(II), Cu(II) and Cd(II) ions onto polyazomethineamides (PAMA) has been investiga... more The removal of Pb(II), Cu(II) and Cd(II) ions onto polyazomethineamides (PAMA) has been investigated using batch adsorption techniques. The extent of adsorption was investigated as a function of pH, adsorbent dose, contact time and initial metal ion concentration. The metal ion removal was pH-dependent and reached maximum at pH 6.0. Experimental data were analysed by Langmuir, Freundlich, Redlich-Peterson and Temkin adsorption isotherms. The characteristic parameters for each isotherms and related correlation coefficients have been determined using MATLAB 7.1. The maximum adsorption capacities of PAMA for Pb(II), Cu(II) and Cd(II) ions were calculated from the Langmuir isotherm 452.1, 470.7 and 462.3 mg/g respectively. Pseudo-first-order, pseudo-second-order, Elovich kinetic and intraparticle diffusion models were used to fit the experimental data. Kinetic parameters, rate constants, equilibrium sorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. The kinetic studies showed that the pseudo-second-order rate equation was better described by the adsorption process. The FT-IR spectra of the adsorbent indicated that the amide, amide carbonyl and azomethine groups were major binding sites with the metal ions. The adsorption of PAMA for heavy metal is selective, and the adsorption capacity is in the order of Cu(II) > Cd(II) > Pb(II).► Synthesis of new adsorbent, polyazomethineamides (PAMA). ► Removal of Pb(II), Cu(II) and Cd(II) ions using PAMA. ► Adsorption of heavy metal ions onto PAMA was pH dependent and optimum pH was 6.0. ► Adsorption capacity is in the order of Cu(II)>Cd(II)>Pb(II). ► Adsorption kinetics was followed by pseudo-second-order model.
Polymer Science Series B, 2008
The polymerization of methyl methacrylate was carried out with the following Ziegler-Natta type i... more The polymerization of methyl methacrylate was carried out with the following Ziegler-Natta type initiating systems: Fe(AcAc)3-AlEt2Br, Fe(AcAc)3-ZnEt2 (acac = acetyl acetonate). Both the catalyst systems are active under homogeneous conditions in benzene at 40°C for methyl methacrylate polymerization. The polymerization kinetics suggests that the average rate of polymerization was first order with respect to [monomer] for both the catalyst systems, and the overall activation energies were found to be 14.0 and 12.8 kcal mol −1.
Journal of Applied Polymer Science, 2009
2,2,6,6-Tetramethyl piperidinoxy (TEMPO) activated with diethyl aluminum bromide was employed as ... more 2,2,6,6-Tetramethyl piperidinoxy (TEMPO) activated with diethyl aluminum bromide was employed as an initiator system for methyl methacrylate polymerization. Effect of addition of Co(acac)3 and VO(acac)2 complexes to the initiators system on methyl methacrylate polymerization were studied in benzene solvent. Various reaction parameters such as Al/TEMPO, monomer concentration, reaction temperature and time applied to the polymerization were investigated. The polymer yields, molecular weight and molecular weight distributions can be controlled with the addition of Co(acac)3 to the initiator system. PMMA's of molecular weight distributions, as low as 1.10 was obtained under relatively mild conditions, in the temperature range 40–60°C in benzene solvent. However, Co and V complexes did not influence the micro structure of the PMMA's formed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Journal of Applied Polymer Science, 2009
Ravikumar, L. and Thevi, R.(2009), Effect of Co and V complexes on polymerization of methyl metha... more Ravikumar, L. and Thevi, R.(2009), Effect of Co and V complexes on polymerization of methyl methacrylate initiated by AlEt 2 Br-TEMPO catalyst. Journal of Applied Polymer Science, 114: 39323938. doi: 10.1002/app. 31012
Environmental Progress & Sustainable Energy, 2013
The removal of Cr (VI) from aqueous solutions onto chemically modified orange peel was studied at... more The removal of Cr (VI) from aqueous solutions onto chemically modified orange peel was studied at varying initial metal concentrations, adsorbent doses, pH and contact times. Batch experiments were carried out under optimized conditions to evaluate the adsorption capacity of the orange peel chemically modified with sodium hydroxide. The residual Cr (VI) concentrations after biosorption were analyzed by FAAS. The biosorbent was characterized by FT-IR spectroscopy and BET. The characterization of the orange peel biomass suggested the possible contribution of carboxyl and hydroxyl groups in Cr (VI) biosorption. Chemically modified orange peel exhibited more adsorption potential as compared to the raw orange peel. The biosorption efficiency of the orange peel was dependent on the pH of the Cr (VI) solution, with pH 2 being optimal. The removal rate of Cr (VI) ions increased with increase in contact time and remained constant after an equilibrium time of 180 min. The removal of Cr (VI) ions increased with increase in biosorbent concentration with the optimal adsorbent dosage at 4.0 mg/L. The increase in initial Cr (VI) ion concentration led to an increase in the percentage removal of Cr (VI). The adsorption data fitted well with the Freundlich isotherm model with R 2 = 0.987 for the raw orange peel and R 2 = 0.995 for the modified orange peel. The Freundlich constants K f and n were 97.07 [mg/g (L/mg) n ] and 0.79 (g/L) for the raw orange peel and 139.0 [(mg/g)(L/mg) n ] and 0.815 (g/L)
High Performance Polymers, 2007
A series of new soluble, thermally stable polymers that contain phenylthiourea and azo groups in ... more A series of new soluble, thermally stable polymers that contain phenylthiourea and azo groups in the polymer backbone were synthesized from a novel bisphenol and diacid chlorides. The novel bisphenol containing phenylthiourea and azo groups was synthesized in three steps. In the first step, 4,4 1bis(thiourea) biphenyl (BTB) was from 4,4 1 2diaminobiphenyl and ammonium thiocynate. The second step involved the diazodization reaction of 4-aminophenol to give the diazonium chloride salt. The third step in the preparation of the monomer was the coupling of bisthiourea (BTB) with the diazonium chloride in the presence of an alkali which resulted in 4,4 1 -bis(p-hydroxyphenyl azo thiourea)biphenyl (HP-ATB). The final step was the synthesis of polyesters by polycondensation reaction of this monomer with various acid chlorides (both aromatic and aliphatic). The materials were characterized by solution viscosity, UV-Vis, Fourier transform infrared spectroscopy, 1 H NMR, differential scanning calorimetry and thermogravimetric analysis. Solubility of the polymers was also tested with different solvents, which can be an important parameter for the processability of the polymer. The synthesis and characterization of the novel monomer and polymers is discussed herein.
Journal of The Chilean Chemical Society - J CHIL CHEM SOC, 2007
Hydrogen titanate nanotubes obtained by hydrothermal synthesis are treated with sol containing ti... more Hydrogen titanate nanotubes obtained by hydrothermal synthesis are treated with sol containing titanium. The products are characterized with transmission electron microscopy, X-ray diffraction, thermal gravimetric analysis, and Raman spectroscopy. Their photocatalytic performance is evaluated by the photocatalytic degradation rates of methyl orange in aqueous solution under UV-vis light irradiation. The results reveal that the treated nanotubes are more thermally stable and exhibit better photocatalytic performance than primary nanotubes. The treated nanotubes can keep a tubular structure when calcined at 400°C. However, their precursors collapse when they are calcined only at 300°C. The more thermally stable new functional TiO 2 nanotubes can be prepared by using sol containing other elements instead of sol containing Ti in the future.
International Journal of Polymeric Materials, 2012
A new aromatic dicarboxylic acid monomer 4-pyridylformylimino-N-(phenyl,2′,5′ – dicarboxylic acid... more A new aromatic dicarboxylic acid monomer 4-pyridylformylimino-N-(phenyl,2′,5′ – dicarboxylic acid) (PPDC) containing pyridine and azomethine units was synthesized through a simple one-step condensation reaction between 2-aminoterephthalic acid and 4-pyridinecarboxaldehyde. A series of new polyamides was prepared through the direct one-pot phosphorylation polycondensation of PPDC with simple aromatic commercial diamines and diamines bearing phenylthiourea groups. The polyamides were characterized by FT-IR, 1H-NMR, and 13C-NMR spectroscopy. Thermal stability of the polymers was evaluated using thermogravimetric analysis. The polyamides with inherent viscosities in the range of 0.30–0.51 dL/g showed an outstanding solubility in various solvents such as 1-methyl-2-pyrrolidone (NMP), dimethly sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimetylacetamide (DMAc), and pyridine. The cured polyamides displayed significantly higher thermal stability than the uncured polyamides. The conductivity of the polyamides, when blended with 20% by weight of doped polyanilines, was in the range 3.09–4.21 × 10−3 S cm−1.
International Journal of Polymeric Materials, 2012
Three new polyazomethines having phenylthiourea groups were synthesized through solution polycond... more Three new polyazomethines having phenylthiourea groups were synthesized through solution polycondensation of terephthalaldehyde with 4,4 0 -bis(thiourea)biphenyl ether, 4,4 0 -bis(thiourea)biphenylmethane, and 4,4 0 -bis(thiourea)biphenyl sulphone. For comparison purposes, simple polyazomethines were prepared by the polycondensation of terephthalaldehyde with 4,4 0 -diaminodiphenyl ether, 4,4 0 -diaminodiphenylmethane, and 4,4 0 -diaminodiphenyl sulphone. Poly(imine)s having phenylthiourea groups were characterized through IR and 1 H-NMR spectroscopic methods and the thermal stability of the polymers were evaluated through TGA analysis. Conductivity of polyaniline synthesized in aqueous p-toluenesulfonic acid was found to be 3.83 Scm À1 . The conductivity of the polymeric blends with polyaniline dopped with p-toluenesulfonic acid and HCl (20% by weight) were found to be in the range 0.16 Â 10 À3 À 5.7 Â 10 À3 Scm À1 .
Open Journal of Polymer Chemistry, 2014
A series of novel ladder-type poly(azomethine amide)s (PAMs) were prepared from new azomethine co... more A series of novel ladder-type poly(azomethine amide)s (PAMs) were prepared from new azomethine containing carboxylic acid monomer (TCA) with simple aromatic diamines and aromatic diamines with thiourea groups (TDAs) by means of phosphorylation polycondensation reaction. Molecular weights of the polyamides were evaluated viscometrically, and the inherent viscosities were in the range of 0.31 -0.58 g/dl. These ladder-type polymers were not freely soluble in common organic solvents. Structure of monomers and polymers were confirmed using FT-IR, 1 H-NMR and 13 C-NMR spectroscopic analysis. Removal of Cu 2+ and Cd 2+ from aqueous solutions by adsorption onto the polyamides was investigated. The effect of pH, initial metal ion concentrations and contact time were studied in batch experiments. The polyamides were found to be highly effective adsorbents for the removal of Cu 2+ and Cd 2+ metal ions from aqueous solutions. In a mixture of metal ions, the selectivity order was found to be Pb(II) > Cu(II) > Cr(IV) > Cd(II).
Materials Chemistry and Physics, 2009
Two new poly (azomethine ester)s were synthesized by direct polycondensation of 4′-hydroxybenzala... more Two new poly (azomethine ester)s were synthesized by direct polycondensation of 4′-hydroxybenzalaniline-4-carboxylic acid (1) and 4′-hydroxy-3′-methoxybenzalaniline-4-carboxylic acid (2) using dichlorophenylphosphine at 140 °C in DMF solvent containing LiCl. Polymers were precipitated by pouring the reaction mixture into water. Monomers and polymers were characterized by viscosity, IR, 1H NMR and TGA. One of the poly (azomethine ester) derived from 4′-hydroxybenzalaniline-4-carboxylic acid (1) when blended with polyaniline/HCl, polyaniline/NH4OH and polyaniline shows conductance in the range 5.6 × 10−11 to 0.78 × 10−3 S cm−1.
Separation Science and Technology, 2012
Novel polyamides bearing pyridyl and azomethine groups as pendant pyridylformylimino groups along... more Novel polyamides bearing pyridyl and azomethine groups as pendant pyridylformylimino groups along with thioamide moieties in the polymer backbone were synthesized using 4-pyridylformylimino-N-(phenyl,2’,5′-dicarboxylic acid) with 4,4′-(bisthiourea)benzidine and 4,4′- diaminodiphenyl methane through one pot phosphorylation polymerization technique. The optimization of experimental conditions and parameters including pH, adsorbent dosage, contact time and initial metal ion concentration for the removal of heavy metal
Polymer-Plastics Technology and Engineering, 2012
... Ramesh a , Lingam Ravikumar b * & Abdul Razak Burkanudeen c pages 140-145. ... IR (KBr): ... more ... Ramesh a , Lingam Ravikumar b * & Abdul Razak Burkanudeen c pages 140-145. ... IR (KBr): 3265cm −1 (-NH 2 ), 3163 cm −1 (-NH), 1065 cm −1 (C = S). 1 H-NMR (δ H , d 6 -DMSO): δ 9.57 (s, 2H, NH), δ 7.28 (d, 4H, phenyl), δ 7.26 (d, 4H, phenyl), δ 3.85 (s, 4H, NH 2 ). ...
European Polymer Journal, 2007
... The authors thank the Secretary, Principal, CBM College, Coimbatore for the facilities. Dr. V... more ... The authors thank the Secretary, Principal, CBM College, Coimbatore for the facilities. Dr. V. Sengodan, Mr. M. Balaji Prasad and Mr. K. Gopalakrishnan, SNR College, Coimbatore for their help in getting the conductivity measurement of the polymer samples. References. ...
Designed Monomers and Polymers, 2009
Recently, soluble poly(azomethine ester)s with good thermal stability and liquid crystalline prop... more Recently, soluble poly(azomethine ester)s with good thermal stability and liquid crystalline properties are much sought after in opto-electronic field. One such attempt was to synthesize poly(azomethine ester)s with a pendent group. In this study, the newly synthesized diacid monomer benzalaniline 3'-4'dimethoxy terepthalic acid was condensed with two diol monomers to get the polymers with pendent benzylidene group. The diacid monomer was characterized by UV, IR, NMR and CHNS analysis. The polymers were characterized by IR, TGA, and for liquid crystalline property. Polymer-I showed the highest thermal stability upto 335˚C. Polymer-II exhibited liquid crystalline nature along with good solubility and thermal stability.
The adsorption studies of poly(6-(ethoxybenzothiazole acrylamide) (PEBTA), for Cu(II) and Zn(II) ... more The adsorption studies of poly(6-(ethoxybenzothiazole acrylamide) (PEBTA), for Cu(II) and Zn(II) metal ions removal from an aqueous solution have been investigated, as a function of solution pH, adsorbent dose, contact time, initial metal ion concentration and temperature. The chemical and structural characteristics of the adsorbent were determined by the FT-IR, 1 H-NMR, TGA, SEM, and EDAX analysis. The maximum adsorption capacities of the adsorbent for Cu(II) and Zn(II) ions, as calculated from the Langmuir isotherm model, were 273.5 and 216.4 mg/g, respectively. The adsorption kinetic studies show that the adsorption of Cu(II) and Zn(II) ions onto PEBTA follows the pseudo second order kinetic model. Thermodynamic parameters such as ΔG1, ΔH1 and ΔS1 were also evaluated, and it has been found that the adsorption process is feasible, spontaneous and exothermic in nature. Desorption studies were carried out using 0.3 N HCl, and it revealed that the adsorbed Cu(II) and Zn(II) ions can be easily removed. The adsorption-desorption process is reversible, and
after in opto-electronic field. One such attempt was to synthesize poly(azomethine ester)s with a... more after in opto-electronic field. One such attempt was to synthesize poly(azomethine ester)s with a pendent group. In this study, the newly synthesized diacid monomer benzalaniline 3’-4’dimethoxy terepthalic acid was condensed with two diol monomers to get the polymers with pendent benzylidene group. The diacid monomer was characterized by UV, IR, NMR and CHNS analysis. The polymers were characterized by IR, TGA, and for liquid crystalline property. Polymer-I showed the highest thermal stability upto 335°C. Polymer-II exhibited liquid crystalline nature along with good solubi- lity and thermal stability.
A series of novel ladder-type poly(azomethine amide)s (PAMs) were prepared from new azomethine co... more A series of novel ladder-type poly(azomethine amide)s (PAMs) were prepared from new azomethine containing
carboxylic acid monomer (TCA) with simple aromatic diamines and aromatic diamines with thiourea groups
(TDAs) by means of phosphorylation polycondensation reaction. Molecular weights of the polyamides were
evaluated viscometrically, and the inherent viscosities were in the range of 0.31 - 0.58 g/dl. These ladder-type
polymers were not freely soluble in common organic solvents. Structure of monomers and polymers were confirmed
using FT-IR, 1H-NMR and 13C-NMR spectroscopic analysis. Removal of Cu2+ and Cd2+ from aqueous
solutions by adsorption onto the polyamides was investigated. The effect of pH, initial metal ion concentrations
and contact time were studied in batch experiments. The polyamides were found to be highly effective adsorbents
for the removal of Cu2+ and Cd2+ metal ions from aqueous solutions. In a mixture of metal ions, the
selectivity order was found to be Pb(II) > Cu(II) > Cr(IV) > Cd(II).
Desalination, 2011
The removal of Pb(II), Cu(II) and Cd(II) ions onto polyazomethineamides (PAMA) has been investiga... more The removal of Pb(II), Cu(II) and Cd(II) ions onto polyazomethineamides (PAMA) has been investigated using batch adsorption techniques. The extent of adsorption was investigated as a function of pH, adsorbent dose, contact time and initial metal ion concentration. The metal ion removal was pH-dependent and reached maximum at pH 6.0. Experimental data were analysed by Langmuir, Freundlich, Redlich-Peterson and Temkin adsorption isotherms. The characteristic parameters for each isotherms and related correlation coefficients have been determined using MATLAB 7.1. The maximum adsorption capacities of PAMA for Pb(II), Cu(II) and Cd(II) ions were calculated from the Langmuir isotherm 452.1, 470.7 and 462.3 mg/g respectively. Pseudo-first-order, pseudo-second-order, Elovich kinetic and intraparticle diffusion models were used to fit the experimental data. Kinetic parameters, rate constants, equilibrium sorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. The kinetic studies showed that the pseudo-second-order rate equation was better described by the adsorption process. The FT-IR spectra of the adsorbent indicated that the amide, amide carbonyl and azomethine groups were major binding sites with the metal ions. The adsorption of PAMA for heavy metal is selective, and the adsorption capacity is in the order of Cu(II) > Cd(II) > Pb(II).► Synthesis of new adsorbent, polyazomethineamides (PAMA). ► Removal of Pb(II), Cu(II) and Cd(II) ions using PAMA. ► Adsorption of heavy metal ions onto PAMA was pH dependent and optimum pH was 6.0. ► Adsorption capacity is in the order of Cu(II)>Cd(II)>Pb(II). ► Adsorption kinetics was followed by pseudo-second-order model.
Polymer Science Series B, 2008
The polymerization of methyl methacrylate was carried out with the following Ziegler-Natta type i... more The polymerization of methyl methacrylate was carried out with the following Ziegler-Natta type initiating systems: Fe(AcAc)3-AlEt2Br, Fe(AcAc)3-ZnEt2 (acac = acetyl acetonate). Both the catalyst systems are active under homogeneous conditions in benzene at 40°C for methyl methacrylate polymerization. The polymerization kinetics suggests that the average rate of polymerization was first order with respect to [monomer] for both the catalyst systems, and the overall activation energies were found to be 14.0 and 12.8 kcal mol −1.
Journal of Applied Polymer Science, 2009
2,2,6,6-Tetramethyl piperidinoxy (TEMPO) activated with diethyl aluminum bromide was employed as ... more 2,2,6,6-Tetramethyl piperidinoxy (TEMPO) activated with diethyl aluminum bromide was employed as an initiator system for methyl methacrylate polymerization. Effect of addition of Co(acac)3 and VO(acac)2 complexes to the initiators system on methyl methacrylate polymerization were studied in benzene solvent. Various reaction parameters such as Al/TEMPO, monomer concentration, reaction temperature and time applied to the polymerization were investigated. The polymer yields, molecular weight and molecular weight distributions can be controlled with the addition of Co(acac)3 to the initiator system. PMMA's of molecular weight distributions, as low as 1.10 was obtained under relatively mild conditions, in the temperature range 40–60°C in benzene solvent. However, Co and V complexes did not influence the micro structure of the PMMA's formed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Journal of Applied Polymer Science, 2009
Ravikumar, L. and Thevi, R.(2009), Effect of Co and V complexes on polymerization of methyl metha... more Ravikumar, L. and Thevi, R.(2009), Effect of Co and V complexes on polymerization of methyl methacrylate initiated by AlEt 2 Br-TEMPO catalyst. Journal of Applied Polymer Science, 114: 39323938. doi: 10.1002/app. 31012
Environmental Progress & Sustainable Energy, 2013
The removal of Cr (VI) from aqueous solutions onto chemically modified orange peel was studied at... more The removal of Cr (VI) from aqueous solutions onto chemically modified orange peel was studied at varying initial metal concentrations, adsorbent doses, pH and contact times. Batch experiments were carried out under optimized conditions to evaluate the adsorption capacity of the orange peel chemically modified with sodium hydroxide. The residual Cr (VI) concentrations after biosorption were analyzed by FAAS. The biosorbent was characterized by FT-IR spectroscopy and BET. The characterization of the orange peel biomass suggested the possible contribution of carboxyl and hydroxyl groups in Cr (VI) biosorption. Chemically modified orange peel exhibited more adsorption potential as compared to the raw orange peel. The biosorption efficiency of the orange peel was dependent on the pH of the Cr (VI) solution, with pH 2 being optimal. The removal rate of Cr (VI) ions increased with increase in contact time and remained constant after an equilibrium time of 180 min. The removal of Cr (VI) ions increased with increase in biosorbent concentration with the optimal adsorbent dosage at 4.0 mg/L. The increase in initial Cr (VI) ion concentration led to an increase in the percentage removal of Cr (VI). The adsorption data fitted well with the Freundlich isotherm model with R 2 = 0.987 for the raw orange peel and R 2 = 0.995 for the modified orange peel. The Freundlich constants K f and n were 97.07 [mg/g (L/mg) n ] and 0.79 (g/L) for the raw orange peel and 139.0 [(mg/g)(L/mg) n ] and 0.815 (g/L)
High Performance Polymers, 2007
A series of new soluble, thermally stable polymers that contain phenylthiourea and azo groups in ... more A series of new soluble, thermally stable polymers that contain phenylthiourea and azo groups in the polymer backbone were synthesized from a novel bisphenol and diacid chlorides. The novel bisphenol containing phenylthiourea and azo groups was synthesized in three steps. In the first step, 4,4 1bis(thiourea) biphenyl (BTB) was from 4,4 1 2diaminobiphenyl and ammonium thiocynate. The second step involved the diazodization reaction of 4-aminophenol to give the diazonium chloride salt. The third step in the preparation of the monomer was the coupling of bisthiourea (BTB) with the diazonium chloride in the presence of an alkali which resulted in 4,4 1 -bis(p-hydroxyphenyl azo thiourea)biphenyl (HP-ATB). The final step was the synthesis of polyesters by polycondensation reaction of this monomer with various acid chlorides (both aromatic and aliphatic). The materials were characterized by solution viscosity, UV-Vis, Fourier transform infrared spectroscopy, 1 H NMR, differential scanning calorimetry and thermogravimetric analysis. Solubility of the polymers was also tested with different solvents, which can be an important parameter for the processability of the polymer. The synthesis and characterization of the novel monomer and polymers is discussed herein.
Journal of The Chilean Chemical Society - J CHIL CHEM SOC, 2007
Hydrogen titanate nanotubes obtained by hydrothermal synthesis are treated with sol containing ti... more Hydrogen titanate nanotubes obtained by hydrothermal synthesis are treated with sol containing titanium. The products are characterized with transmission electron microscopy, X-ray diffraction, thermal gravimetric analysis, and Raman spectroscopy. Their photocatalytic performance is evaluated by the photocatalytic degradation rates of methyl orange in aqueous solution under UV-vis light irradiation. The results reveal that the treated nanotubes are more thermally stable and exhibit better photocatalytic performance than primary nanotubes. The treated nanotubes can keep a tubular structure when calcined at 400°C. However, their precursors collapse when they are calcined only at 300°C. The more thermally stable new functional TiO 2 nanotubes can be prepared by using sol containing other elements instead of sol containing Ti in the future.
International Journal of Polymeric Materials, 2012
A new aromatic dicarboxylic acid monomer 4-pyridylformylimino-N-(phenyl,2′,5′ – dicarboxylic acid... more A new aromatic dicarboxylic acid monomer 4-pyridylformylimino-N-(phenyl,2′,5′ – dicarboxylic acid) (PPDC) containing pyridine and azomethine units was synthesized through a simple one-step condensation reaction between 2-aminoterephthalic acid and 4-pyridinecarboxaldehyde. A series of new polyamides was prepared through the direct one-pot phosphorylation polycondensation of PPDC with simple aromatic commercial diamines and diamines bearing phenylthiourea groups. The polyamides were characterized by FT-IR, 1H-NMR, and 13C-NMR spectroscopy. Thermal stability of the polymers was evaluated using thermogravimetric analysis. The polyamides with inherent viscosities in the range of 0.30–0.51 dL/g showed an outstanding solubility in various solvents such as 1-methyl-2-pyrrolidone (NMP), dimethly sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimetylacetamide (DMAc), and pyridine. The cured polyamides displayed significantly higher thermal stability than the uncured polyamides. The conductivity of the polyamides, when blended with 20% by weight of doped polyanilines, was in the range 3.09–4.21 × 10−3 S cm−1.
International Journal of Polymeric Materials, 2012
Three new polyazomethines having phenylthiourea groups were synthesized through solution polycond... more Three new polyazomethines having phenylthiourea groups were synthesized through solution polycondensation of terephthalaldehyde with 4,4 0 -bis(thiourea)biphenyl ether, 4,4 0 -bis(thiourea)biphenylmethane, and 4,4 0 -bis(thiourea)biphenyl sulphone. For comparison purposes, simple polyazomethines were prepared by the polycondensation of terephthalaldehyde with 4,4 0 -diaminodiphenyl ether, 4,4 0 -diaminodiphenylmethane, and 4,4 0 -diaminodiphenyl sulphone. Poly(imine)s having phenylthiourea groups were characterized through IR and 1 H-NMR spectroscopic methods and the thermal stability of the polymers were evaluated through TGA analysis. Conductivity of polyaniline synthesized in aqueous p-toluenesulfonic acid was found to be 3.83 Scm À1 . The conductivity of the polymeric blends with polyaniline dopped with p-toluenesulfonic acid and HCl (20% by weight) were found to be in the range 0.16 Â 10 À3 À 5.7 Â 10 À3 Scm À1 .
Open Journal of Polymer Chemistry, 2014
A series of novel ladder-type poly(azomethine amide)s (PAMs) were prepared from new azomethine co... more A series of novel ladder-type poly(azomethine amide)s (PAMs) were prepared from new azomethine containing carboxylic acid monomer (TCA) with simple aromatic diamines and aromatic diamines with thiourea groups (TDAs) by means of phosphorylation polycondensation reaction. Molecular weights of the polyamides were evaluated viscometrically, and the inherent viscosities were in the range of 0.31 -0.58 g/dl. These ladder-type polymers were not freely soluble in common organic solvents. Structure of monomers and polymers were confirmed using FT-IR, 1 H-NMR and 13 C-NMR spectroscopic analysis. Removal of Cu 2+ and Cd 2+ from aqueous solutions by adsorption onto the polyamides was investigated. The effect of pH, initial metal ion concentrations and contact time were studied in batch experiments. The polyamides were found to be highly effective adsorbents for the removal of Cu 2+ and Cd 2+ metal ions from aqueous solutions. In a mixture of metal ions, the selectivity order was found to be Pb(II) > Cu(II) > Cr(IV) > Cd(II).
Materials Chemistry and Physics, 2009
Two new poly (azomethine ester)s were synthesized by direct polycondensation of 4′-hydroxybenzala... more Two new poly (azomethine ester)s were synthesized by direct polycondensation of 4′-hydroxybenzalaniline-4-carboxylic acid (1) and 4′-hydroxy-3′-methoxybenzalaniline-4-carboxylic acid (2) using dichlorophenylphosphine at 140 °C in DMF solvent containing LiCl. Polymers were precipitated by pouring the reaction mixture into water. Monomers and polymers were characterized by viscosity, IR, 1H NMR and TGA. One of the poly (azomethine ester) derived from 4′-hydroxybenzalaniline-4-carboxylic acid (1) when blended with polyaniline/HCl, polyaniline/NH4OH and polyaniline shows conductance in the range 5.6 × 10−11 to 0.78 × 10−3 S cm−1.
Separation Science and Technology, 2012
Novel polyamides bearing pyridyl and azomethine groups as pendant pyridylformylimino groups along... more Novel polyamides bearing pyridyl and azomethine groups as pendant pyridylformylimino groups along with thioamide moieties in the polymer backbone were synthesized using 4-pyridylformylimino-N-(phenyl,2’,5′-dicarboxylic acid) with 4,4′-(bisthiourea)benzidine and 4,4′- diaminodiphenyl methane through one pot phosphorylation polymerization technique. The optimization of experimental conditions and parameters including pH, adsorbent dosage, contact time and initial metal ion concentration for the removal of heavy metal
Polymer-Plastics Technology and Engineering, 2012
... Ramesh a , Lingam Ravikumar b * & Abdul Razak Burkanudeen c pages 140-145. ... IR (KBr): ... more ... Ramesh a , Lingam Ravikumar b * & Abdul Razak Burkanudeen c pages 140-145. ... IR (KBr): 3265cm −1 (-NH 2 ), 3163 cm −1 (-NH), 1065 cm −1 (C = S). 1 H-NMR (δ H , d 6 -DMSO): δ 9.57 (s, 2H, NH), δ 7.28 (d, 4H, phenyl), δ 7.26 (d, 4H, phenyl), δ 3.85 (s, 4H, NH 2 ). ...
European Polymer Journal, 2007
... The authors thank the Secretary, Principal, CBM College, Coimbatore for the facilities. Dr. V... more ... The authors thank the Secretary, Principal, CBM College, Coimbatore for the facilities. Dr. V. Sengodan, Mr. M. Balaji Prasad and Mr. K. Gopalakrishnan, SNR College, Coimbatore for their help in getting the conductivity measurement of the polymer samples. References. ...
Designed Monomers and Polymers, 2009
Recently, soluble poly(azomethine ester)s with good thermal stability and liquid crystalline prop... more Recently, soluble poly(azomethine ester)s with good thermal stability and liquid crystalline properties are much sought after in opto-electronic field. One such attempt was to synthesize poly(azomethine ester)s with a pendent group. In this study, the newly synthesized diacid monomer benzalaniline 3'-4'dimethoxy terepthalic acid was condensed with two diol monomers to get the polymers with pendent benzylidene group. The diacid monomer was characterized by UV, IR, NMR and CHNS analysis. The polymers were characterized by IR, TGA, and for liquid crystalline property. Polymer-I showed the highest thermal stability upto 335˚C. Polymer-II exhibited liquid crystalline nature along with good solubility and thermal stability.
The adsorption studies of poly(6-(ethoxybenzothiazole acrylamide) (PEBTA), for Cu(II) and Zn(II) ... more The adsorption studies of poly(6-(ethoxybenzothiazole acrylamide) (PEBTA), for Cu(II) and Zn(II) metal ions removal from an aqueous solution have been investigated, as a function of solution pH, adsorbent dose, contact time, initial metal ion concentration and temperature. The chemical and structural characteristics of the adsorbent were determined by the FT-IR, 1 H-NMR, TGA, SEM, and EDAX analysis. The maximum adsorption capacities of the adsorbent for Cu(II) and Zn(II) ions, as calculated from the Langmuir isotherm model, were 273.5 and 216.4 mg/g, respectively. The adsorption kinetic studies show that the adsorption of Cu(II) and Zn(II) ions onto PEBTA follows the pseudo second order kinetic model. Thermodynamic parameters such as ΔG1, ΔH1 and ΔS1 were also evaluated, and it has been found that the adsorption process is feasible, spontaneous and exothermic in nature. Desorption studies were carried out using 0.3 N HCl, and it revealed that the adsorbed Cu(II) and Zn(II) ions can be easily removed. The adsorption-desorption process is reversible, and