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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 #102439
Title: SOME NOVEL APPLICATIONS FOR CROSS-LINKED POLYESTERS BASED ON VEGETABLE OILS

Author
item Shogren, Randal

Submitted to: Annual Meeting of the Bio Environmentally Degradable Polymer Society
Publication Type: Abstract Only
Publication Acceptance Date: 8/18/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The disposal of used polyethylene (PE) agricultural mulch film has become a serious problem worldwide. Paper mulch is a feasible alternative to PE, but paper loses most of its strength when wet and degrades too quickly in soil to be effective. In an attempt to alleviate these shortcomings, kraft paper was impregnated with vegetable oil-based resins and then tested for wet strength, rate of biodegradation in soil, and the ability to inhibit weed growth. Resins included oxidatively polymerized soybean and linseed oils and a polyester formed by the reaction of epoxidized soybean oil (ESO) and citric acid. Wet strengths were significantly higher for resin coated papers (4-10 MPa) than uncoated paper (0.5 MPa). Rates of weight loss during soil burial for resin coated papers (40-90% oil added) were about 1/5 of those for uncoated papers or paper coated with unpolymerized oils. When tested as mulches on the top of soil, uncoated paper largely disin- tegrated by 8 weeks while resin coated papers maintained their integrity for 8-12 weeks (long enough for most crops). Flexible polyurethane foams are used extensively for cushioning but cannot be recycled, are made from highly toxic reactants, and give off toxic combustion products. It was found that a flexible foam formed spontaneously during the reaction of ESO and polycarboxylic acids such as citric acid. Foaming probably occurs due to simultaneous reaction of epoxy and acid groups to give the polyester and release of blowing agent (water) as adjacent carboxyl groups dehydrate to form anhydrides. The resulting foam was very flexible and resilient but had a rather low strength. Polyesters made with ESO and sebacic acid were tested for their ability to act as absorbents. Such absorbents may be use- ful in bioremediation where both could be disposed of by biodegradation.