The influence of sodium carboxy methyl cellulose (CMC) on the curing process of epoxy resin E44 with 4

4'-diamino diphenyl methane (DDM) was studied by using infrared spectra and thermal analytical methods. Infrared spectra indicated that the CMC contributed to forming more polyether structures during the curing process. The study of non-isothermal curing kinetics by differential scanning calorimeters (DSC) showed that CMC accelerated curing reaction of E44/DDM and reduced reaction activation energy in the initial reaction stage. The iso-conversional method and the autocatalytic model were used to analyze the curing process of E44/DDM and CMC/E44/DDM systems respectively. A kinetic model was built. The changes of activation energy (E) versus conversion (a) were obtained by the Starink's iso-conversional method for E44/DDM system and CMC/E44/DDM systems respectively. The activation energy (E) of E44/DDM system was reduced obviously with increasing conversion. When CMC content was the same

activation energy of the CMC system with high molecular weight was higher than that with low molecular weight. However

for the CMC/E44/DDM system

as the degree of conversion increased

variation of E was not obvious. The SB (m

n) autocatalytic kinetic model was used to describe the curing reaction process of the studied system. The model parameters were calculated by using the Levenberg-Marquardt method. The SB model showed a good agreement with experimental data of CMC/E44/DDM system. However

the SB model showed a relatively bad agreement with experimental data of E44/DDM system. An E variable autocatalytic kinetic model was proposed to describe the curing process of E44/DDM system due to the obvious change of activation energy and the model parameters calculated with the Levenberg-Marquardt method. Compared with the SB model

this model showed a better agreement with the experimental data of E44/DDM system. The results of the research provide theoretical basis for improvement of manufacturing process and optimization of processing window.