ADVANCED STARCH-BASED MATERIALS FOR NON-FOOD APPLICATIONS
Location: Plant Polymer Research
Title: GREEN COMPOSITES OF POLY(LACTIC ACID) AND OILSEED CO-PRODUCTS
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 2, 2006
Publication Date: October 21, 2006
Citation: Finkenstadt, V.L., Liu, C., Evangelista, R.L., Liu, L.S., Cermak, S.C., Hojillaevangelist, M.P., Willett, J.L. 2006. Green composites of poly(lactic acid) and oilseed co-products [abstract]. UJNR Annual Meeting. P.21.
Poly(lactic acid)(PLA) is a biodegradable plastic made from renewable resources and has similar mechanical properties to polypropylene. PLA is more expensive than petroleum-based plastics, and the use of low-cost fillers as extenders is desirable. Agricultural co-products (AcP) of oilseed crops were collected after initial processing. Cuphea (C), Lesquerella (L) and Milkweed (M) are oil seed crops. PLA was melted in a twin-screw extruder then AcP (0%, 8%, 15%, 22%, 30% and 45% w/w) was added producing a homogeneous resin which was injection molded. As AcP content increased, tensile strength for all PLA composites decreased as predicted by the Nicolais-Narkis model. PLA-C exhibited increased stiffness. In contrast, the modulus of PLA-M & PLA-L decreased slightly. Unexpectedly, PLA-M showed extensive stress-cracking under tensile stress and exhibited an elongation value 50% to 200% more than the PLA control. Acoustic emission showed ductile behavior of the PLA-milkweed composite.