Mechanical and fracture properties of ternary PE/PA6/GF composites

This article studies the mechanical properties of short fiber reinforced polymer blends comprised of a soft thermoplastic matrix (polyethylene, PE), a rigid dispersed thermoplastic phase (polyamide-6, PA6) and glass fiber reinforcement. These ternary composites are designed as a model system to investigate the impact of the mutual interactions of the three phases on the composite mechanical properties. For this purpose two types of fibers are used, dispersed-phase and matrix-phase compatible fibers, respectively.The addition of the PA6 phase to the matrix PE increases the strength of the blend, but lowers its toughness as it decreases the elongation at break. When fibers are added the blends become relatively brittle. The composites containing dispersed-phase compatible fibers show enhanced tensile modulus and strength. This enhancement is associated with the formation of a network within the polymeric matrix comprised of glass fibers welded together by the minor component. While improving the strength, this type of reinforcement decreases the toughness of the composites compared to the case of matrix compatible fibers.