S. M. Sayyah

Kinetic studies of the aqueous oxidative polymerization of 3-hydroxyaniline and characterization of the polymer obtained

The aqueous polymerization of 3-hydroxyaniline (3HA) was studied using sodium dichromate as oxidant in presence of hydrochloric acid. The effect of hydrochloric acid, sodium dichromate and monomer concentration on the polymerization rate, specific viscosity of the obtained polymer and a.c.conductivity was investigated. The initial and overall reaction rates increase with the increase in hydrochloric acid concentration or sodium dichromate concentration but decrease with the increase in the monomer concentration. The specific viscosity values increase with increasing of hydrochloric acid concentration or monomer concentration which means that the molecular weight of the polymer samples increases in the same direction. But the molecular weight decreases with increasing sodium dichromate concentration. The highest a.c. conductivity value of the obtained polymer was found in case of using 0.0019 g mol/L of Na 2 Cr 2 O 7 , 0.1 M HCl and 0.1 M monomer solution in the reaction medium. Some electrical properties of this sample were investigated as a function of temperature. The order of the polymerization reaction with respect to hydrochloric acid, Na 2 Cr 2 O 7 and monomer concentration was found to be 1.13, 1.2 and m 0.909 respectively. The apparent activation energy (E a ) for this polymerization system was found to be 6.1248 2 10 4 J/mol. The obtained poly(3-hydroxyaniline) was characterized by UV-visible, IR spectroscopy, X-ray diffraction analysis and electron microscopy studies. The thermogravimetric analysis (TGA) and differential thermal analysis (DTA) results were used to confirm the structure.

Kinetic studies of the chemical polymerization of substituted aniline in aqueous solutions and characterization of the polymer obtained Part 1. 3-Chloroaniline

Aqueous polymerization of 3-chloroaniline (mCA) was studied using sodium dichromate as oxidant in the presence of hydrochloric acid. The effect of hydrochloric acid, sodium dichromate and monomer concentration on the polymerization rate, specific viscosity of the obtained polymer and ac conductivity was investigated. The initial and overall reaction rates increase with increasing hydrochloric acid concentration or sodium dichromate concentration, but decrease with increasing monomer concentration. The specific viscosity values (η sp ) increase with increasing hydrochloric acid concentration or monomer concentration, which means that the molecular weight of the polymer samples increases accordingly. On the contrary, the molecular weight decreases with increasing sodium dichromate concentration. The highest ac conductivity value of the obtained polymer was found for 0.0255 moll -1 of Na 2 Cr 2 O 7 , 0.8 moll -1 HCl and 0.0956 moll -1 monomer concentration in the reaction medium. The order of the polymerization reaction with respect to hydrochloric acid, Na 2 Cr 2 O 7 and monomer concentration was found to be 1.0, 0.9 and 0.75, respectively. The apparent activation energy (E a ) for this polymerization system was found to be 13.674 x 10 4 mol -1 . The obtained poly(3-chloroaniline) was characterized by UV-visible, IR and 1 H NMR spectroscopy. X-ray diffraction analysis and electron microscopy studies were carried out. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) results were used to confirm the structure.

Aqueous oxidative polymerization of 3-methoxyaniline and characterization of its polymer

The aqueous polymerization of 3-methoxyaniline (3-OMeA) was studied using sodium dichromate as oxidant in presence of hydrochloric acid. The effect of hydrochloric acid, sodium dichromate, monomer concentration and reaction temperature on the polymerization rate, specific viscosity of the obtained polymer and a.c.conductivity was investigated. The initial and overall reaction rates increase with the increasing of hydrochloric acid concentration, reaction temperature or sodium dichromate concentration but decrease with the increasing of the monomer concentration. The specific viscosity values increase with the increasing of the hydrochloric acid concentration or the monomer concentration which means that the molecular weight of the polymer samples increases in the same direction. But the molecular weight decreases with the increase of both sodium dichromate concentration and reaction temperature. The highest a.c.conductivity value of the obtained polymers was found when 0.0205 g mol/L of Na 2 Cr 2 O 7 , 0.8 g mol/L HCI and 0.0821 g mol/L of monomer were used in the reaction medium at 5C, the electrical conductivity and dielectric constant of this polymer sample were investigated as a function of temperature. The order of the polymerization reaction with respect to hydrochloric acid, Na 2 Cr 2 O 7 and monomer concentration was found to be 0.85, 1.36 and 0.74 respectively. The apparent activation energy (E a ) for this polymerization system was found to be 7.656 2 10 4 J/mol. The obtained poly(3-methoxyaniline) was characterized by UV-visible and IR spectroscopy, X-ray diffraction analysis and electron microscopic studies. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) results were used for the confirmation of the suggested structure.

Kinetic Studies of the Polymerization of Substituted Aniline in Aqueous Solutions and Characterization of the Polymer Obtained

Abstract The aqueous polymerization of m-methylaniline (mMA) was studied using sodium dichromate as oxidant in the presence of hydrochloric acid. The effect of hydrochloric acid, sodium dichromate and monomer concentration on the polymerization rate, specific viscosity of the obtained polymer and a.c.conductivity was investigated. The initial and overall reaction rates increase with the increase of hydrochloric acid concentration or sodium dichromate concentration but decrease with the increase of the monomer concentration. The specific viscosity values increase with increasing of hydrochloric acid concentration or monomer concentration, which means that the molecular weight of the polymer samples increases in the same direction. But the molecular weight decreases with the increase of sodium dichromate concentration. The highest a.c.conductivity value of the obtained polymer was found in case of using 0.023304 g mol/L of Na2Cr2O7 0.2 M HCI and 0.093225 M monomer solution in the reaction medium. The order of the polymerization reaction with respect to hydrochloric acid, Na2Cr2O7 and monomer concentration was found to be 1.3, 1.33 and —0.83 respectively. Reaction Rate = k 2[HCI]1.3[oxidant]1.33(monomer]−0.83 The apparent activation energy (E a) for this polymerization system was found to be 4.594 × 104 J/mol. The obtained poly(m-methylaniline) was characterized by uv-visible and IR spectroscopy. X-ray diffraction analysis and electron microscopy studies were carried out. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) results were used for the confirmation of the structure.

Study of ferroelectricity in polyaniline

Polymerization of aniline (ANI) was achieved in aqueous medium using sodium dichromate as oxidant in presence of hydrochloric acid. The obtained polyaniline was characterized by X-ray diffraction and electron microscopic studies. The thermogravimetric analysis (TGA) and differential thermal analysis (DTA) results were used to study thermal degradation of the polymer. The unusually high dielectric constant of the produced polyaniline gives an indication for the important dielectric properties of the prepared PANI. The present study confirmed the observation of ferroelectricity of the prepared polyaniline with a Curies temperature at 323 K. This observation is unique concerning this polymer which has the advantage of being prepared at room temperature. The ferroelectric phenomenon of this conducting polymer was confirmed by studying pyroelectricity, (P-E) hysteresis loop and polarization as a function of temperature.

Copolymerization of Benzylidene malononitrile with methyl methacrylate and spectroscopic studies before and after irradiation with gamma rays of the obtained copolymer

Benzylidene malononitrile (BMN) monomer was prepared from the condensation of benezaldehyde with malononitrile in absolute ethanol as a reaction medium using few drops of piperidine as a catalyst at the reflux temperature for one hour. This monomer (BMN) was copolymerized with methyl methacrylate (MMA) by solution polymerization technique in the presence of benzoyl peroxide as a free radical initiator using dimethyl formamide as a reaction medium in a sealed tube under a nitrogen atmosphere at 65°C. The Kelen-Tudös and Fineman-Ross were used to determine the copolymerization parameters of MMA (M 1 ) and BMN (M 2 ) monomers. It was found that, the reactivity ratios r 1 and r 2 for MMA and BMN are equal to 2.45, 0.12 - 0.05 respectively. Alfrey Price (Q) and (e) values were calculated and the obtained data indicated that the copolymer structure is a block system. Also, infrared, 1 H-NMR and UV-visible spectroscopic studies for the obtained copolymer were performed. Further UV-visible studies of the PMMA film blended with 1% by weight of the prepared MMA-BMN copolymer were carried out before and after irradiation with different gamma doses in the range from 0-100 KGy.

AQUEOUS OXIDATIVE CHEMICAL POLYMERIZATION OF N-METHYLANILINE IN ACID MEDIUM AND CHARACTERIZATION OF THE OBTAINED POLYMER

The oxidative chemical polymerization of N-methylaniline was studied in hydrochloric acid solution using sodium dichromate as oxidant at 5°C under nitrogen atmosphere. The effect of hydrochloric acid, sodium dichromate and monomer concentration on the polymerization reaction was investigated. The order of reaction with respect to hydrochloric acid, sodium dichromate and monomer concentration was 0.816, 0.735 and −0.83 respectively. Also, the effect of temperature on the polymerization rate was studied and the apparent activation energy of this polymerization reaction was found to be 1.999×104 J/mol. The characterization of the obtained polymer sample at the optimum conditions was carried out by IR, UV-visible, 1H-NMR, X-ray diffraction, electron microscope and thermogravimetric analysis. The ac conductivity of the obtained polymer samples was measured and the highest values were found for the samples prepared at hydrochloric acid, sodium dichromate and monomer concentrations of 0.200, 0.0094 and 0.1869 mol/L respectively at 5°C.

Surface Activity of Monomeric and Polymeric (3-alkyloxy aniline) Surfactants

ABSTRACT The adsorption and micellization processes of 3-alkyloxy aniline namely [3-decyloxy aniline (C10M), 3-dodecyloxy aniline (C12M) and 3-cetyloxy aniline (C16M)] and their polymers [C10P, C12P and C16P] have been investigated using surface tension (γ) measurements at different temperatures. The synthesized monomers and polymers have been characterized by IR and elemental analysis. The surface and thermodynamic parameters of these monomeric and polymeric surfactants are investigated. The results show that the critical micelle concentration (CMC) of the polymeric surfactants is lower than that of monomers. The CMC values decreases as the hydrophobic chain lengthens for both monomeric and polymeric surfactants. The surface parameters show the ability of monomeric and polymeric surfactants to adsorb at the air/water interface and decrease the surface tension. The thermodynamic parameters reveal that the micellization process is spontaneous for all investigated surfactants. The specific conductance measurements show that the specific conductance increases with increasing chain length of the substituted alkyl groups, the synthesized polymeric surfactants have higher values of specific conductance than the corresponding monomers and the specific conductance increases with rising solution temperature.

Oxidative chemical polymerization of some 3-alkyloxyaniline surfactants and characterization of the obtained polymers

Meta-hydroxyaniline was reacted with decyl bromide, dodecyl bromide, and cetyl bromide to produce new aniline derivative surfactants. The monomers (0.4 mol/L) were polymerized in aqueous solution of hydrochloric acid (1.0 mol/L) using sodium dichromate (0.1 mol/L) as oxidant at room temperature. The crstallinity of the prepared polymer samples was investigated by X-ray diffraction and electron microscopic analysis. The thermal behavior of these polymers was studied by thermogravimetric analysis (TGA), also the electrical properties of the obtained polymer samples were measured and discussed. The a.c.-electrical conductivity was found to be increased by the increase of number of carbon atoms in the substituted alkyl group in the following order (cetyl > dodecyl > decyl).

Electropolymerization of o-Aminobenzoic Acid and Characterization of the Obtained Polymer Films

ABSTRACT Poly(ortho-aminobenzoic acid), as a ring substituted derivative of aniline, has been synthesized electrochemically from acid medium on platinum electrode. The reaction parameters such as current density, hydrochloric acid concentration, monomer concentration, temperature, and reaction duration time were investigated. The kinetic study shows that the orders of polymerization reaction are 1.01, 1.33, and 0.41 with respect to hydrochloric acid concentration, monomer concentration, and current density, respectively. The apparent activation energy (Ea) is found to be 134.8 kJ mol−1. The polymer films obtained have been characterized by cyclic voltammetry, X-ray diffraction, elemental analysis, thermogravimetric analysis, scanning electron microscopy, 1H-NMR, and IR spectroscopy. The mechanism of the electrochemical polymerization reaction has been discussed.