Investigation on Foamed Polypropylene/Nano‐Talc/Ethylene Propylene Diene Monomer Composites in a Combined In‐Mold Decoration and Microcellular Injection Molding Process

ABSTRACT A combined in‐mold decoration and microcellular injection molding (IMD/MIM) method is used in this paper. The blend materials' rheological and crystallization characteristics are thoroughly examined, shedding light on how ethylene propylene diene monomer (EPDM) influences their properties. Additionally, the cellular structure, surface quality, and mechanical properties of the foamed parts are analyzed, revealing the blend materials' impact on both the macroscopic and microscopic attributes of the foamed components. The signal‐cell and double‐cell representative volume element (RVE) model are built in Digimat to study the variation of stress distribution with time under tensile and shear loads. The results show that the addition of EPDM reduces the fluidity of the melt and makes the viscosity of the PP/nano‐talc blend system higher. The foamed composite has the largest cell diameter and the smallest cell density when the EPDM content is 20%. The addition of elastomer EPDM has only a minor influence on the interfacial bonding behavior of PP film and PP matrix, and the apparent quality is high. When the EPDM content is between 10% and 30%, it notably enhances the impact resistance of foamed material. However, this improvement comes at the cost of a reduction in tensile and flexural strength.