Curing kinetics and mechanisms of polysulfone nanofibrous membranes toughened TGDDM/DDS were investigated by using isothermal DSC and NIR, and compared to those of TGDDM/DDS and PSF films toughened TGDDM/DDS. At early curing stage, the Curing rate of nanofibrous membranes toughened system was faster than those of other two systems, whereas the final conversion of toughened systems was lower than that of resin matrix. Most of the primary amine Was Consumed by gelation and the concentration of secondary amine reached the maximum around gelation. The faster consuming rates of primary and secondary amines in nanofibrous membranes toughened system resulted in higher concentration of hydroxyl groups and tertiary amines at gelation, which led to larger amounts of branching and crosslinking compared to resin matrix. The comparison of the results obtained from two methods showed that the epoxide conversion exhibited identical variations as a function of time, as well as the curing rate. (C) 2009 Elsevier B.V. All rights reserved.