MECHANICAL BEHAVIOR AND CRACK PROPAGATION IN INJECTION-MOLDED POLYAMIDE 6/CLAY NANOCOMPOSITES

摘要

The crystalline structure and mechanical behavior of injection-molded polyamide 6 (PA6) reinforced with 2 wt.% polymer-intercalated nano-layered silicate (montmorillonite) is studied. X-ray diffraction and differential scanning calorimetry show that the presence of layered silicate in PA6 nanocomposites lead to the formation of a different crystalline structure when compared with unmodified PA6. Considerably improved tensile strength and modulus obtained from the nano-layered silicates while maintaining the ductility of the PA6 matrix indicate that strong matrix-filler ionic interactions and very high specific area and aspect ratio of the polymer intercalated-layered silicates characterized this nanocomposite. In the conditioned state, while an elasto-plastic fracture with extensive tearing is observed in unmodified PA6, a linear-elastic fracture is observed in the PA6 nanocomposite.