Abstract:The increasing demand for lightweight, high‐performance polypropylene (PP) products has accelerated the development of foaming‐based injection molding technologies. The combined chemical foaming and microcellular injection molding (CF/MIM) process offers a promising solution by generating uniform cellular structures that enhance mechanical properties. However, achieving stable foaming remains challenging due to complex interactions between chemical blowing agents (CBAs) and physical blowing agents (PBAs). While previous studies have examined CBAs and PBAs separately, their combined effects on foaming efficiency, crystallization, and mechanical performance remain insufficiently explored. This study investigates the synergistic effects of azodicarbonamide (ADC), an exothermic CBA, and supercritical N2 (SC‐N2), a PBA, in CF/MIM. Compared to CFIM and MIM, CF/MIM with 1 wt% ADC and 0.10% SC‐N2 achieves equivalent foaming efficiency to CFIM with 2 wt% ADC and MIM with 0.38% SC‐N2. CF/MIM products exhibit an 11.53% increase in crystallinity, 5.61% higher tensile strength, and 5.99% greater flexural strength than CFIM. Additionally, CF/MIM promotes β‐crystal formation, enhances elongation at break by 26.28%, and reduces weight by 114.20% compared to MIM with 4 wt% ADC. These findings demonstrate that ADC and SC‐N2 significantly enhance CF/MIM performance, providing insights for optimizing lightweight, high‐strength PP manufacturing.
Highlights:Improved ADC dispersion achieves a uniform cellular structure.Lower escape velocity of SC‐N2 forms a stable cell structure.Formed uniform and stable cellular structures enhance mechanical properties.Larger gas generation from ADC boosts weight reduction and foaming.