Effects of silanization and modification treatments on the stiffness and toughness of BF/SEBS/PA6,6 hybrid composites

Abstract

To develop basalt fiber (BF)-reinforced PA6,6 composites with an optimal balance between stiffness and toughness, the effects of fiber surface treatments and the addition of rubber elastomers on the microstructural characteristics of these composites was investigated and their effects on their physico-mechanical properties was thoroughly characterized. It was confirmed that amine-silanized BF/SEBS-g-MAH/PA6,6 ternary composites have a high chemical affinity and that the constituent components are highly compatible. In contrast, MAH-silanized BF/SBBS-c-NH2/PA6,6 ternary composites shows that the fiber and rubber phases disperse separately, thereby enhancing both the stiffness and toughness of the composites individually. These two composite systems had both similarities and differences in terms of their mechanical properties, such as the strength, stiffness, toughness, and viscoelastic behavior, based on their microstructural characteristics. Compared with BF/PA6,6, the impact strength of the amine-silanized BF/SEBS-g-MAH/PA6,6 ternary composites was significantly improved, by 57.7%, but the tensile and flexural strengths decreased. Despite forming a miscible blend, the addition of SEBS-g-MAH only contributed to improving the toughness of the composites at the expense of stiffness. The tensile and impact strengths of the MAH-silanized BF/SBBS-c-NH2/PA6,6 ternary composites increased by 6.4% and 23.8%, respectively, thus demonstrating an improved balance between their stiffness and toughness. These results suggest that MAH-silanized BF/SBBS-c-NH2/PA6,6 ternary composites may be attractive materials for industrial applications because the silanized BFs and SEBS elastomers provide complementary reinforcement, thus efficiently improving the composites’ stiffness and toughness.