Properties of protective loose-fill foams

Abstract

This study compared the performance of eight commercial starch and expanded polystyrene (EPS)-based loose-fill foam products. Density of starch-based foams is higher, by a factor of two to three times, than either EPS-based ones. Compressive stress of most starch-based foams did not differ significantly from 0.0893 MPa value for virgin EPS foam. EPS- and starch-based foams have predominantly a closed and open cellular structure, respectively. Resiliency or elastic recovery of starch-based foams had values between 69.5 and 71.25%, which is about 10% lower than virgin EPS foam. Friability of both starch- and EPS-based foams was between 2 and 6 wt %, but starch-based foams broke into a fine dust, whereas EPS-based foams broke into large fragments. After conditioning at 20, 50, and 80% r.h., 23°C and 50% r.h., 35°C, the water content for starch-based foams averaged 6.0, 9.5, 14, and 8.5 wt %, respectively. The mechanical properties of starch-based foams were more sensitive to changes in relative humidity and temperature than EPS-based foams, but the higher amount of absorbed moisture did not compromise its mechanical integrity. © 1998 John Wiley & Sons, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America. J Appl Polym Sci 67:1157–1176, 1998