Free-radical trapping in the precipitation polymerization of acrylamide

• Published in: Journal of polymer science. Part B, Polymer physics Vol. 41; no. 11; pp. 1192 - 1197
• Main Authors: Guha, Suparna, Rao, T. R. Gundu, Mandal, Broja M.
• Format: Journal Article
• Language: English
• Published: New York Wiley Subscription Services, Inc., A Wiley Company 01.06.2003; Wiley
• Subjects: Applied sciences; ESR/EPR; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; polyacrylamide; Polymerization; precipitation polymerization; Preparation, kinetics, thermodynamics, mechanism and catalysts; radical polymerization; water-soluble polymers; Solvent effect; Experimental study; Spin trapping; Solution polymerization; Free radical; radical polymerization; Heterogeneous polymerization; Free radical polymerization; ESR/EPR; Acrylamide polymer; Chemical concentration; water-soluble polymers; Kinetics; Rate constant; polyacrylamide; Precipitation polymerization
• ISSN: 0887-6266; 1099-0488
• DOI: 10.1002/polb.10476

Electron spin resonance spectroscopy revealed that some free radicals were trapped in the precipitated polymer during the precipitation polymerization of acrylamide conducted in nonsolvents of the polymer [t‐butyl alcohol (TBA), acetone and methanol]. The trapped radical concentration decreased with an increase in the chain‐transfer activity of the aforementioned liquids. A 100% polymerized acrylamide in TBA prepared with a 10% monomer concentration and a 3 × 10−3 mol/dm3 azobisisobutyronitrile concentration at 50 °C contained approximately 2 radicals per 100 polymer molecules. The trapped radicals on exposure to air decayed with time according to second‐order kinetics. The rate constant was evaluated and found to be in reasonably good agreement with the rate constant evaluated from data published long ago for the decay of trapped polyacrylonitrile radicals following their exposure to air. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1192–1197, 2003