The effects of different shear flows on polymeric reaction between poly(styrene/maleic anhydride) (SMA) and polyamide 6 (PA6) in heterogeneous blending system were investigated. FTIR, SEM, rheometry, and GPC were used to qualitatively analyze the reaction, and the reaction apparent activation energy was determined as 75.7 kJ/mol by a rheological method. To study the effects of different shear flows on heterogeneous polymeric reaction, a more practical technique was developed to select the data that only responds to the reaction without the effect of different shear flows. Avrami's equation was employed to analyze the reaction process under shear flow and the results showed that the half period (t(1/2)) of reaction process decreased with the increase of the shear rate in this study. Moreover, the decease rates were different in the different shear modes as follows: the half period decreased slightly under the oscillatory shear, whereas it decreased strongly under the steady shear. The possible reasons for these phenomena were discussed. (c) 2008 Wiley Periodicals, Inc.