Plastic recycling is a major challenge, particularly for polymers found in waste from electrical and electronic equipment (WEEE). Efficient recycling of these materials requires additional sorting steps that are not currently implemented at the industrial scale. Consequently, recovered polymers are obtained as heterogeneous blends with mechanical properties significantly lower than those of virgin materials. WEEE are mainly composed of acrylonitrile butadiene styrene (ABS) and high-impact polystyrene (HIPS), two amorphous polymers with immiscible styrenic matrices [1]; styrene–acrylonitrile (SAN) for ABS and polystyrene (PS) for HIPS, both toughened by dispersed polybutadiene nodules. As a result, ABS/HIPS blends exhibit a multiphase morphology with two distinct populations of polybutadiene nodules, leading to reduced mechanical performance, particularly toughness [2]. Both polymers deform following a crazing and/or shearing deformation behaviour which are influenced by polybutadiene nodules distribution. Blends were prepared by twin-screw extrusion to study the effect of residence time. Impact tests (free-falling dart) reveal that shorter residence times increase toughness. Injection-moulded blends are also produced, studying the influence of shear rate during injection and mould temperature. The mechanical properties are measured by tensile and Izod impact testing. The different blend morphologies obtained through these two processing methods with varying parameters are observed with Atomic Force Microscopy (AFM). The position and diameter of larger nodules are detected semi-automatically on AFM images with a modulus contrast. Meshes are generated from the multi-phase microstructures. Finite elements (FE) simulations are developed to correlate blend morphology with damage mechanisms, by investigating crazing and shear deformation. A visco-plastic behaviour of the multi-phase material with cavitation of the polybutadiene nodules is implemented. Future work will focus on comparing the simulated crazing with the diffraction pattern obtained from the crazes in in situ tensile SAXS experiments.