The thermokinetic behavior of polymethyl methacrylate (PMMA)-based composites during the pultrusion of glass fiber reinforced composites was investigated using a mathematical model accounting for the heat transfer and heat generation during the reaction. The equations of continuity and energy balance, coupled with a kinetic expression for the reaction system were solved using a finite difference method to calculate the temperature profiles in the thickness direction in a rectangular pultrusion die. A kinetic model, dP/dt = -eta A(o)exp(-E(p)/RT) (2[I](o) - [Z](o)) P(m)(1-P/P(f))(n) (1 - exp ( - k(d)(t - t(z)))), was proposed to describe the reaction behavior of a PMMA resin. Kinetic parameters for the model were found from isothermal differential scanning calorimetry (DSC) scans using a multiple regression technique. The kinetic parameters gA(o) = 1.459 x 10(9) min(-1), E(p) = 10.62 kcal/mol, m = 1.095, and n = 0.893 were obtained. The predictions of the model will be compared with experimental results. It can be found that the theoretical predicted values of temperature profiles along the pultrusion die length were in good agreement with experimental data, which implies that the mathematical model was suitable for the pultrusion processes. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 2228-2233, 2012