Foamed articles based on potato starch, corn fibers and poly(vinyl alcohol)

Single-use packaging materials made of expanded polystyrene (EPS) have been identified as suitable items to be replaced by biodegradable materials. Plates made with EPS represent a source of non-degradable waste that is difficult to collect and to recycle. Potato starch based foamed plates have been prepared by a baking process. Presently, foam plates have been prepared by baking aqueous mixtures of potato starch, corn fibers, and poly(vinyl alcohol) (PVA) inside a hot mold. The effects of the addition of corn fibers, a co-product of bio-ethanol production, on mechanical properties and moisture resistance of potato starch based foamed plates were investigated. The addition of corn fiber to potato starch batter increased baking time and an increased batter volume is needed to form a complete tray. The mechanical properties of the trays decreased with added corn fiber. In previous studies PVA has been added as aqueous solution to improve strength, flexibility, and water resistance of baked starch trays. In this study, 88% hydrolyzed PVA was added as a powder in the mixture, avoiding the time consuming and costly step of pre-dissolving the PVA. The addition of PVA to potato starch batters containing corn fiber mitigated the reduction in tensile properties seen in trays with added corn fiber. Starch-based trays produced with a high fiber ratio and PVA, showed improved water resistance.