Starch-based microcellular foams
AssigneeThe United States of America as represented by the Secretary of Agriculture
InventorsGregory M. Glenn, Donald J. Stern
Life of this patent
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Abstract
Starch-based microcellular foams composed of a solid matrix with a network of small open cells or pores are described. The foams have high pore volume, low density, and high surface area, and are prepared using a process wherein an aqueous gel prepared from gelatinized starch is treated to exchange the water in the gel with air while maintaining the integrity of the network of open cells or pores. The starch-based microcellular foams are particularly useful for encapsulation and later release of a substance.
Claims5
A starch-based microcellular foam comprising a solid phase matrix of gelatinized starch having an amylose content of at least 40% or greater amylose, said solid phase matrix having therein a network of small open cells having a liquid or solid substance encapsulated therein, wherein the density of said solid phase matrix in the absence of said encapsulated liquid or solid substance is about 0.32 gm/cm.sup.3 or less, and the surface area is 50 m.sup.2 /gm or greater and wherein at least about 80% of said open cells of said matrix are about 10 .mu.m or smaller in size.
A method of encapsulating a liquid or solid substance for later release, which comprises encapsulating said liquid or solid substance with a starch-based microcellular foam comprising a solid phase matrix of gelatinized starch having an amylose content of at least 40% or greater amylose, said solid phase matrix having therein a network of small open cells wherein the density of said solid phase matrix in the absence of said encapsulated liquid or solid substance is about 0.32 gm/cm.sup.3 or less, and the surface area is 50 m.sup.2 /gm or greater and wherein at least about 80% of said open cells of said matrix are about 10 .mu.m or smaller in size.
Dependencies are inferred from the claim text.