Starch-based semipermeable films
AssigneeThe United States of America as represented by the Secretary of Agriculture
InventorsFelix H. Otey, Richard P. Westhoff
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Abstract
Semipermeable films useful as dialysis membranes are prepared from starch-based composites. The films are shaped by conventional methods from a plasticized matrix comprising highly gelatinized starch and ethylene acrylic acid copolymer neutralized with a strong alkali. These films are remarkably transparent and resistant to degradation in the presence of aqueous solutions.
Claims16
A method of preparing a semipermeable film comprising the following steps:
- a. converting a mixture comprising a starchy material (SM), an ethylene acrylic acid copolymer (EAA), and a strong alkali into a plasticized matrix, wherein the ratio of SM:EAA is in the range of 20:80 to about 60:40 parts on a dry weight basis, wherein the strong alkali is present in an amount sufficient to neutralize substantially all of the EAA, and wherein the starchy material in the plasticized matrix is highly gelatinized;
- and
- b. shaping said matrix into a film.
A semipermeable film composition comprising a dry composite of highly gelatinized starchy material (SM) and a sodium or potassium salt of ethylene acrylic acid copolymer (EAA), wherein the ratio of SM:EAA copolymer salt is in the range of 20:80 to 60:40 parts on a dry weight basis.
Dependencies are inferred from the claim text.