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 di chromate as oxidant in the presence of hydrochloric acid. The effect of hyd rochloric acid, sodium dichromate and monomer concentration on the polymeri zation rate, specific viscosity of the obtained polymer and ac conductivity was investigated. The initial and overall reaction rates increase with inc reasing hydrochloric acid concentration or sodium dichromate concentration, but decrease with increasing monomer concentration. The specific viscosity values (eta (sp)) increase with increasing hydrochloric acid concentration or monomer concentration, which means that the molecular weight of the pol ymer samples increases accordingly. On the contrary, the molecular weight d ecreases with increasing sodium dichromate concentration. The highest ac co nductivity value of the obtained polymer was found for 0.0255 mol 1(-1) of Na2Cr2O7, 0.8 mol 1(-1) HCl and 0.0956 mol 1(-1) monomer concentration in t he reaction medium. The order of the polymerization reaction with respect t o hydrochloric acid, Na2Cr2O7 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 H-1 NMR spect roscopy. X-ray diffraction analysis and electron microscopy studies were ca rried out. Thermogravimetric analysis (TGA) and differential thermal analys is (DTA) results were used to confirm the structure. (C) 2001 Society of Ch emical industry.