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

Abstract

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 (ηsp) 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 mol l−1 of Na2Cr2O7, 0.8 mol l−1 HCl and 0.0956 mol l−1 monomer concentration in the reaction medium. The order of the polymerization reaction with respect to hydrochloric acid, Na2Cr2O7 and monomer concentration was found to be 1.0, 0.9 and 0.75, respectively. The apparent activation energy (Ea) for this polymerization system was found to be 13.674 × 104 mol−1. The obtained poly(3-chloroaniline) was characterized by UV–visible, IR and 1H 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. © 2001 Society of Chemical Industry