Journal of Applied Polymer Science, Vol.75, No.2, 239-246, 2000
Kinetics of azo-initiated 1-vinyl-2-pyrrolidone polymerizations at low conversions in aqueous media
The free-radical polymerization behavior of 1-vinyl,2-pyrrolidone (NVP) was studied at low conversions, using capillary dilatometry. The aqueous media were kept at neutral pH and the studies were conducted isothermally, at 40 or 45 degrees C. The ate-type initiators used were 4,4'-azobis-4-cyanopentanoic acid (ACPA), 2,2'-azobisisobutyronitrile (AZBN), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane dihydrochloride] (ABDH). The monomer concentration and initiator concentration ranges were 1.17-2.34 mol L-1 and 1-8 mmol L-1, respectively. The rates of polymerization (R-p) and orders of reaction with respect to NVP and the initiator were evaluated and the kinetic equations were found to be R-p proportional to [NVP] [ACPA](1.2); R-p proportional to [NVP] [AZBN](1.1); and R-p proportional to [NVp](2.2) [ABDH](1.1). The polymers obtained were characterized by their viscosity numbers and correlation of the viscosity average molecular weights made with the type and amount of the azo initiator. (C) 2000 John Wiley & Sons, Inc.
Keywords:ACRYLAMIDE