Rubber-toughened polyamide 6/clay nanocomposites

Toughening of polyamide 6 (PA6) based nanocomposites (PN’s), with 3 wt% organically modified montmorillonite (OMMT), was investigated by blending with up to 40 wt% of maleinized styrene–ethylene/butadiene–styrene copolymer (mSEBS). The nanostructure of the PA6 matrix did not change on blending with mSEBS, nor did the nature of the two polymeric phases on addition of OMMT. The morphology of the rubber particles in the PN’s was homogeneous, with particle sizes larger than those of the corresponding blends, due to limitations imposed by the clay on the compatibilizing effect of the mSEBS. All the PN’s were ductile and, despite the incorporation of rubber, showed higher small strain tensile properties than those of the corresponding blends. Super-tough nanocomposites were obtained with 30 wt% mSEBS. The critical interparticle distance to attain super-toughness (τc) was slightly larger in the blends than in the PN’s, indicating that an increased modulus of the matrix on addition of OMMT leads to smaller τc values.