Acrylamide was polymerized in acetonitrile at 82 degrees C with a perfluorinated azo-derivative initiator. The polymerization proceeded heterogeneously. Varying amounts of initiator and monomer were used. The activation energy was deduced from three experiments carried out at 59, 71, and 82 degrees C. The following kinetic law, deviating a great deal from the classical law, was obtained: R-pi similar to [I-2](o)(0.76)[M](o)(1.06)(0.05% < [I-2](o)/[M](o) < 1.00%) and R-pi similar to [I-2](o)(0.29)[M](o)(1.95)(1% < [I-2](o)/[M](o) < 7%). These results can be interpreted in light of the contribution of primary radical termination and the emergence of occlusion. The development of a new kinetic relationship allowed us to confirm the existence of both of these termination reactions. The calculation of the k(prt)/K-i . k(p) ratio was also achieved.