Facile Preparation of Open‐Cell PP/TPS Blend Foams Using Water as a Blowing Agent

Extrusion foaming using water as a blowing agent offers a green process of preparing polymer foams. Due to the low water solubility of hydrophobic polymers such as polypropylene (PP), it is difficult to produce low‐density foams of such pure polymers. In this study, starch was utilized as an effective water carrier and open‐cell PP/thermoplastic starch (TPS) blend foams with apparent density as low as 19.5 kg · m −3 and open‐cell content of 95.6% were successfully prepared. A possible expansion mechanism is also proposed to better understand the observed foaming behavior. The PP/TPS blend foams with low density and high open‐cell content are found to be a promising candidate absorbent material for oil spill cleanup application.