Effect of poly(oxyalkylene)amines on structure and properties of epoxide nanocomposites

A shortcoming of most polymer nanocomposites is relatively low toughness. An effective method to eliminate this is the use of a suitable combination of polymeric impact modifiers with organoclay, which may impart synergistic effects on the mechanical behavior of both thermoplastic and thermoset matrix nanocomposites. This work focuses on the effect of various combinations of amine‐terminated (APOP) and hydroxyl‐terminated poly(oxypropylene) (POP) and layered silicates on the structure and mechanical behavior of epoxy nanocomposites. The combination of APOP and POP with 0.5−5% wt % of organoclay leads to some compositions that produce well balanced mechanical behavior of the epoxy nanocomposite. The higher toughening effectiveness of APOP/montmorillonite (MMT) compared with that of POP/MMT is a consequence of formation of blended domains consisting of clay tactoids and fine APOP inclusions. An increase in the dispersed particle size with clay content was observed to be a consequence of more significant clay‐induced nucleation of phase separation at the expense of clay‐induced accelerated curing. The best mechanical behavior was observed for materials using an adduct of APOP and MMT, which was obtained using the ion exchange of sodium ions of MMT by protonated APOP. The enhanced mechanical behavior was due to the formation of nanosized planar arrays by self‐pilling of elastomer‐modified clay and the corresponding increase in the T g of the epoxy. The structure/property relationships of these systems indicate that this type of clay polymer combination provides an effective way of modifying the mechanical behavior of epoxy nanocomposites. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012