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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Plant Polymer Research » Research » Publications at this Location » Publication #81024
Title: STARCH-BASED FOAMED ARTICLES PREPARED BY A BAKING PROCESS

Author
item Shogren, Randal
item Lawton Jr, John
item TIEFENBACHER, KARL - FRANZ HAAS MACH. OF AM.

Submitted to: Annual Meeting of the Bio Environmentally Degradable Polymer Society
Publication Type: Abstract Only
Publication Acceptance Date: 9/20/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A process for preparing shaped foam articles from starch has recently been described. This involves baking a starch-water batter inside a hot mold. A thin-walled object such as a plate or cup is formed as the starch gelatinizes, expands out through small vents and dries. In an effort to improve flexibility and water resistance, we have studied how process and formulation parameters influence the structure and physical properties of these baked foams. Baked starch foams had a dense outer skin and a less dense interior with large, mostly open cells. Swollen granule fragments remained in the foam. Overall foam density and strength increased with increasing starch concentration, molecular weight and amylose content while flexibility tended to increase with decreasing density. Foams made from tuber starches such as potato had lower densities and higher flexibilities than those made from cereal starches such as corn. Foam flexibility at low humidity and water resistance was markedly improved by addition of 10-30% polyvinyl alcohol (PVOH) to starch batters. Scanning electron micrographs revealed a phase separated morphology in which swollen starch granules were embedded in a matrix of PVOH. The PVOH component crystallized to a high degree during baking. Cross-linking agents were added to starch batters to give further increases in water resistance. (Research conducted under cooperative research and development agreement 58-3K95-M-228 between USDA/ARS and Franz Haas Machinery of America).