Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 8, 1996
Publication Date: N/A
Interpretive Summary: In the established 90 million lb/yr loose-fill packing foam market, starch utilization will increase at the expense of synthetic materials. For starch to become an alternative to synthetic materials, the performance of starch-based products must be similar to that of synthetic-based ones. This study compared the performance of eight commercial starch and expanded dpolystyrene loose-fill packing foams. Even though starch-based products absorbed more moisture than expanded polystyrene-based products, their mechanical performance was not compromised.
Technical 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 2 to 3 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 71.2% which is about 10% lower than virgin EPS foam. Friability of both starch- and EPS-based foams was between 2 and 6 weight %, 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 deg C and 50% r.h., 35 deg C, the water content for starch-based foams averaged 6.0, 9.5, 14, and 8.5 weight % respectively. The mechanical lproperties of starch-based foams were more sensitive to changes in relativ humidity and temperature than EPS-based foams, but the higher amount of absorbed moisture did not compromise its mechanical integrity.