Study on the mechanical behavior and morphology of ABS/TPU/CNT nanocomposites

Acrylonitrile butadiene styrene (ABS) has comparatively good mechanical properties, but its low fluidity limits the injection molding of thin parts. In this research, acrylonitrile butadiene styrene/thermoplastic polyurethane (ABS/TPU) blends and ABS/TPU nanocomposites containing multi-walled carbon nanotubes (MWCNT) were produced by employing a twin-screw extruder and injection molding. The morphology of fracture surfaces was studied by scanning electron microscopy. The tensile, flexural and impact properties as well as melt fluidity of different specimens were evaluated. The addition of TPU to ABS substantially increased the melt flow index (MFI), but decreased the mechanical properties. The presence of carbon nanotubes in ABS/TPU blend improved mechanical properties and expanded the plastic deformation of fractured surfaces. The maximum tensile and flexural strengths were obtained by applying 0.3 and 0.5 wt.% MWCNT, respectively. The notched impact strength in nanocomposite containing 0.1 wt.% CNT showed about 95% increase in comparison with ABS/TPU blends. The appropriate dispersion of carbon nanotubes and their adhesion to polymer matrix were considered as the most important factors in improving mechanical properties.