Starch/fiber/poly(lactic acid) foam and compressed foam composites

Abstract

Composites of starch, fiber, and poly(lactic acid) (PLA) were made using a foam substrate formed by dehydrating starch or starch/fiber gels. PLA was infiltrated into the dry foam to provide better moisture resistance. Foam composites were also compressed into plastics using force ranging from 4–76 MPa. Tensile strength increased with increasing compression force applied to the foam sample. The samples became increasingly transparent with compression forces approaching 76 MPa. PLA infusion into starch and starch/fiber foam composites resulted in PLA content of 20% and 33%, respectively and provided moisture resistance to the outer regions of the foam samples. The PLA-infused foam samples increased in tensile strength when compressed up to 29 MPa. The PLA-infused compressed samples had greater moisture resistance and had intermediate rates of mineralization compared to the control samples.