Dynamic mechanical spectrometry analysis of modifications in the cure kinetics of polyepoxy composites with particulate fillers

We have performed an analysis of the modifications of a polyepoxy cure kinetics due to the introduction of organic and inorganic particulate fillers. In a previous work 1 we have studied by differential scanning calorimetry the rates of reaction of a polyepoxy system reinforced with particulate fillers. This work revealed very important differences between the kinetics of the polyepoxy and those of the composites ( polyepoxy reinforced). As a matter of fact, the results obtained with the composites do not fit with any literature models. For this reason, we have decided to focus our work on the various possible interactions between the polyepoxy system and the fillers. In order to bring to light elements of understanding to the origins of cure kinetics modifications, several factors have been examined by turns. On one hand, the influence of residual curing stresses, water content, variations in thermal conductivity, and viscosity has been observed. This let us show that any modification of these parameters can induce important cure kinetic modifications, but none of them is at the origin of the observed modifications. On the other hand, several TTT diagrams obtained for various fillers contents by mechanical spectrometry have been constructed. The analysis of those diagrams revealed that the presence of particulate fillers is of great influence on the main phase transitions that occur during the crosslinking reaction. The set of results shows that some physical bonds develop between the polyepoxy network and the organic particles. None but those latter can occasion the consequent modifications of cure kinetics that have been observed.