Starch-lignin foam is bio-based, providing reduced dependence on petroleum re-serves, and making it eligible for DOD purchasing preferences.
It has been known that bio-based polymer products provide sustainability gains through a reduced dependence on petroleum reserves, and that if the products are biodegradable, they also provide environmental amelioration through increased disposal options. Low-cost biodegradable plastics and composites are especially sought for high volume applications where large amounts of material are discarded soon after use, as is the case with many types of packaging and some consumer products.
The present invention provides a bio-based and biodegradable alternative to expanded polystyrene (EPS) for the production of single or short-term use packaging foams. It has been discovered that a biodegradable and water-resistant packaging foam can be prepared by co-extruding two polymeric materials that are abundantly commercially available. The two polymeric materials require no chemical modification prior to use, and the extrusion process makes the two polymeric components compatible. The resulting foam retains its integrity after immersion in water for 24 hours. At 10% lignin, the foam is water/moisture resistant.
(1) Starch-lignin foam is bio-based, providing reduced dependence on petroleum reserves, and making it eligible for DOD purchasing preferences.
(2) Biodegradable, providing increased disposal options and lower levels of greenhouse gases.
(3) At 10% lignin, there are no deleterious effects on foam density, morphology, compressive strength, or resiliency compared with extruded starch foam.
(4) The starch need not be chemically modified by derivitization, thereby reducing material costs, and offsetting the cost of the lignin additive.