Spinning disk reactor (SDR) technology has been demonstrated to achieve significant enhancements in free radical polymerization rates. The effect on the rate may be attributed to the unique hydrodynamic environment experienced by the reacting polymer films. The rotating surface of a SDR promotes extension of the polymer chains, which may prevent the propagating chains from terminating through bimolecular reactions. In this article, a numerical simulation is performed to investigate how reduced rates of termination would affect time conversion behavior of free radical initiated styrene polymerization. Comparisons have been made between model predictions and SDR experimental results. The closeness between predicted and experimental results yields strong evidence that the hydrodynamic regime created on the surface of a SDR can lead to reduced rates of bimolecular termination. (C) 2003 Wiley Periodicals, Inc.