Designer petals shape ZnO nanoparticles as nucleating agents: Verification the mechanism of cavity nucleation in the polymer for foaming

Abstract

The morphology, size and surface roughness of the nucleating agent significantly affect the nucleation effect for foaming in the polymer. In this work, four nucleating agents with different morphologies, namely DE, MS, OMMT and β- CD as heterogeneous nucleation agents were selected for a polypropylene (PP) foaming injection molding process to explore nucleation mechanism. A theoretical assumption (cavity nucleation) in polymer foaming had been put forward about how to enhance the efficiency of bubble nucleation based on classical nucleation theory (CNT). Subsequently, the cavity nucleation was validated by chemical core-back injection foaming molding and in-situ visualization and elaborated by establishing a formula. Finally, designed petals shape particles as nucleating agents to further test this theory. The confirmation of this theory effectively improved the nucleation efficiency and foaming quality, which has important guiding significance to the development of lightweight products.

Keywords

• Visualization
• Cavity nucleation
• Core-back injection molding
• Nucleating agent