Epoxy-Amine Based Nanocomposites Reinforced by Silica Nanoparticles. Relationships between Morphologic Aspects, Cure Kinetics, and Thermal Properties

In general, the incorporation of nanoparticles into polymers shows an increase of the materials performances, but the effect of the nanosized objects is still not well understood. In this study, we have investigated the impact of incorporation of silica nanoparticles in an epoxy/amine (DGEBA/mPDA) system. Naked silica nanoparticles (SiNP) were synthesized via a sol-gel technique. To evaluate the interfacial effect on properties of nanocomposites, the surface of the nanoparticles was modified by substituting silanol groups into epoxide functions (SiNPEp). A new method was elaborated for obtaining different organic-inorganic nanocomposites with a very good dispersion without any aggregation according to transmission electron microscopy (TEM) analyses. The influence of the different silica nanoparticles (SiNP or SiNPEp) on the mechanisms of the reaction between epoxy and amine groups is highlighted. Important new inputs on the cure kinetics of the epoxy/amine mixture are given. The glass transition temperatures and thermal properties of nanocomposites have been examined, and relationships have been established.