Single-use packaging articles made of expanded polystyrene (EPS) are currently used to serve and pack a variety
of food and non-food products. Recently, there have been efforts to develop and commercialize materials from
renewable resources such as starch to replace EPS. Starch based foams are, however, brittle and sensitive to water,
and thus require expensive coating steps when exposure to cold or hot liquids is required. In this report, various
modified starches and additives were tested in baked foam plate formulations to improve strength and water
resistance properties in lieu of coating. Foam plates made from chemically modified starches had shorter baking
times, lighter weights and higher elongations at break than unmodified starch. Plates made from genetically modified
(waxy) starches and polyvinyl alcohol (PVOH) had elongations to break at low humidities, which were much higher
than those made from normal starches and PVOH. Addition of softwood fibers increased starch foam plate strengths
at low and high humidities. Addition of monostearyl citrate to starch batter formulations gave the best improvement
in water resistance among the compounds tested. Baked foams made from potato amylopectin, PVOH, aspen fiber
and monostearyl citrate appeared to have adequate flexibility and water resistance to function as clamshell-type hot
sandwich containers. Published by Elsevier Science B.V.