Evaluation of a biodegradable foam for protective packaging applications

Green Cell (R) foam (GCF) is a biodegradable foam packaging material produced from a proprietary cornstarch blend. It is commercially available in a variety of laminations and constructions. Cushioning ability and thermal resistance (R-value) are the fundamental properties needed to compete against synthetic foams. Since GCF is starch based and biodegradable, a concern was that moisture would likely affect its physical properties. Cushioning characteristics and insulation R-values of 1 and 2 inch foams were determined as a function of temperature and moisture content. The ASTM method D1596 was used to determine the cushioning properties and an ice melt test was used to determine the thermal resistance. Moisture sorption isotherms were developed at three temperatures (20, 25 and 30 degrees C) to determine its moisture sensitivity. The 1-inch-thick foam had lower G values at lower static stresses than synthetic foams, but had higher G values at higher static stresses. The 2-inch-foam had G values similar to that of synthetic foam materials. Dimensional changes were observed at higher relative humidity (RH) conditions, especially at 30 degrees C. The R-values at higher humidities were also less than that of synthetic materials. Copyright (C) 2007 John Wiley & Sons, Ltd.