Amorphous polyamide/maleated styrene–ethylene–co-butylene–styrene nanocomposites: effects of clay loading and compatibilizer content on morphology and mechanical properties

Abstract

The effect of the organoclay content on the toughness of a rubbery modified amorphous polyamide (aPA)/organoclay-based nanocomposite was studied by changing the modifier (maleic anhydride) content. The dispersed rubber particle size decreased markedly with the addition of the modifier, indicating compatibilization of the nanocomposite. However, the particle size of the dispersed phase increased slightly with the organoclay content due to the interactions between the dissolved surfactant and the compatibilizer. Furthermore, we observed that the organoclay resided in the aPA matrix, and that its dispersion remained constant upon rubber addition. This resulted in materials with high stiffness and extremely large toughness values, as measured by both the standard impact strength and the essential work of the fracture method. Because the rubber content was kept constant, the inorganic part of the clay was proposed to be the main parameter that controls toughness. The impact strength of an amorphous polyamide/organoclay nanocomposite has been increased by means of a rubber modified with maleic anhydride (MAH). The organoclay resided in the polyamide matrix and maintained dispersed rubber particle size upon rubber addition. The changes of the dispersed rubber particle size with modifier and nanoclay addition indicated compatibilization of the nanocomposites and interactions between the dissolved surfactant and the rubber modifier. The obtained nanocomposites had a high stiffness and extremely large toughness values, as determined both by impact strength measurements and by the essential work of fracture method.