Effect of inorganic nanoparticles on polypropylene in‐mold decoration and microcellular foaming injection molding composites

In this paper, the surface morphology of the parts was improved by the in‐mold decoration and microcellular foaming injection molding (MIM‐IMD), and the mechanical properties of the parts were improved by inorganic particles modification. The effects of different inorganic particles (CaCO 3 , MMT, Talc) on the rheological behavior, crystallization properties, cell structure, surface quality, and mechanical properties of the MIM‐IMD composites were analyzed through experimental research and comprehensive macro and micro characterization. It was found that the foamed composite added with MMT had the highest surface quality, the best cell structure, the minimum average cell diameter of 78.4 μm and the maximum cell density of 3.09 × 10 6 cells/cm 3 . Talc improved the crystallinity of polypropylene (PP) matrix, and the resulting mechanical properties were the most significant improvement. Tensile, flexural, and impact strength were increased by 20.3%, 11.6%, and 45.2%, respectively. Highlights The MIM‐IMD process was used to improve the surface quality of the samples. The enhancement of different inorganic particles on the properties were compared. The properties were evaluated by macro‐ and micro‐characterization. Inorganic particles can significantly improve the cell structure. Inorganic particles can greatly improve mechanical properties.