Investigation of foaming and mechanical properties of olefin block copolymer/talc/polypropylene composites in IMD/MIM processes

Abstract

In advancing towards carbon neutrality in the automotive industry, polypropylene (PP) plays a crucial role in improving fuel efficiency and reducing carbon emissions as a pivotal lightweight material. However, PP faces challenges in microcellular foaming, including surface quality concerns, intricate molding parameters, and compromised mechanical strength, limiting its broader application. This research introduces an innovative strategy by integrating Olefin Block Copolymer (OBC) into the Talc/PP composite framework using In-mold Decoration/Microcellular Injection Molding (IMD/MIM) techniques to overcome these limitations. Experimental findings reveal that modulating the OBC proportion substantially enhances the PP composites' functionality. Notably, an inclusion of 10 wt% OBC decreases the material's viscosity, and raising the OBC level to 30 wt% markedly improves surface quality with fewer defects. Analyzing cell configuration confirms OBC's beneficial effect on cell size and distribution, particularly in the homogeneity of cells across the material's layers. For mechanical performance, incorporating OBC increased the impact strength from 13.2 kJ/m² to 17.9 kJ/m², highlighting OBC's potential in enhancing PP's toughness. This study enriches our understanding of optimizing PP-based microcellular foamed materials, supporting the development of next-generation lightweight materials. Future efforts will focus on further refinement of the OBC/Talc/PP system for superior performance and practical industrial viability.