Investigation of cell wall thickness and impact strength of polypropylene microcellular nanocomposite foams produced by batch process

Nowadays polymeric nanocomposite foams have attracted the attentions in both academic and industrial communities due to their advantages. Foams with open-cell structures have high ability to absorb sound, water, impact and moisture. The cell wall thickness can be used as a parameter to evaluate the approaches for achieving open-cell structures. In this study the structural and mechanical properties of polypropylene/nano Fe2O3 nanocomposite foams were investigated in batch foaming process using CO2 gas as blowing agent. Nano Fe2O3 content, foaming temperature and foaming time were considered as variable parameters. Design of experiments using L9 orthogonal array of Taguchi approach was used for studying cell wall thickness and specific impact strength. The signal to noise ratio and analysis of variance were carried out. The scanning electron microscope results showed that appropriate microcellular structures with cell density of 109 and 1010 cell/cm3 were achieved. The results indicated that foaming temperature was the most effective parameter on the properties of nanocomposite foams. Decreasing foaming temperature leads to decreasing cell wall thickness and increasing specific impact strength. Also, the results illuminated that specific impact strength was enhanced almost 20% by increasing 4 wt% of nano Fe2O3.