|Biodegradable laminated films fabricated from mixtures of pectin and poly(vinyl alcohol)|
Films made from natural products are of increasing scientific and commercial interest. These films are not only biodegradable but may be recyclable as well as acceptable for pharmaceutical applications. Multiple uses, ease of disposal and the replacement of petroleum-based raw materials with renewable agricultural products make these types of films excellent candidates for commercial development.
Pectin, a polysaccharide found in plant cell walls is biodegradable while poly(vinyl alcohol) (PVA), a synthetic polymer, is much less so. Both materials are water soluble. As films, pectin/PVA blends are more flexible than pectin alone and stronger than PVA alone. A blend of the two would increase biodegradability of PVA while maintaining its mechanical and solubility properties. In addition, pectin/PVA blends offer a range of strength and flexibility properties intermediate between either pectin or PVA. This is a simpler alternative to increasing PVA biodegradability as opposed to grafting starch onto it. It is envisioned that these blends could replace pure PVA in applications where enhanced biodegradability is desirable.
At present, annual use of PVA in the United States is 57,000 tons. Total yearly PVA sales in the US are $400 million. Pectin is an agricultural waste product; commercial pectin is made primarily from citrus fruits and citrus pectin is currently priced at $6.00 to $8.00 per pound, depending on the grade. The current annual production of citrus pectin is approximately 40 million pounds, however, the raw materials are available to increase this significantly.
Pectin and PVA are compatible over a full range of compositions. Pectin/PVA blends have the potential to be blow molded, extruded, cast into films, or injection molded. Plasticizers may also be included in the mixtures in order to increase film flexibility. Possible applications include: coatings for controlled release of, protection of, or adhesives for pharmaceutical preparations to the skin; water soluble pouches for dispensing pre-measured and/or hazardous substances; and dissolvable bags for washing linens of hospital patients with infectious diseases.
The technology has been patented and is available for licensing. The Eastern Regional Research Center is interested in exploring the possibilities of collaboration with a company on the further development of this product though a Cooperative Research and Development Agreement.
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