SURFACTANT MEDIATED POLYMERIZATION KINETICS OF ACRYLAMIDE USING CR(VI)-CYCLOHEXANONE REDOX SYSTEM

Abstract

The effect of organized surfactants on the kinetics of acrylamide (AM) polymerization have been studied over a temperature range of 25–45°C using Cr (VI)-cyclohexanone (CH) redox system as initiator. The rate of polymerization, R_p(obs), as well as, the percentage of the monomer conversio were found to be increased with increasing the concentration of the anionic surfactant (SDS), above its CMC. But the cationic surfactant (CTAB) reduced the rate considerably at higher concentration, while non-ionic surfactant (TX-100) played no role on the rate. The effect of [Cr(VI)], [CH], [AM], [H+], and ionic strength on the rates have also been examined. The presence of 0.015M SDS decreased the overall activation energy of the polymerization by 6.28 k.Cal/ mole as compared to that in the absence of a surfactant. On increasing the SDS concentration, the viscosity average molecular weight was also found to increase. For the polymerization process, a mutable mechanistic scheme has been pro-posed.

Keywords:

• Redox System
• Micellar Polymerization
• Acrylamide
• Surfactant

ACKNOWLEDGEMENT

The authors are thankful to the Head of the Department of Chemistry, Sambalpur University for extending Laboratory facilities M. Patra wishes to thank CSIR, India for the SRF position.