Submitted to: Woodfiber Plastics Composites Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: August 27, 1996
Publication Date: N/A
Interpretive Summary: Starch is an attractive material for use in plastic composites because of its low cost and inherent biodegradability. The addition of starch to plastic materials generally reduces the strength to unacceptable levels, due to the poor adhesion between the plastic and the starch. Special additives called compatibilizers can increase the strength of starch-filled dplastics. Formulations of starch-filled plastics, with and without compatibilizers, were studied. The addition of the compatibilizer improved the strength of the materials. These results further the understanding of starch-filled materials and are of benefit to researchers in the area of utilization of starch in plastics. Products developed from starch-filled plastics could substantially reduce the amount of solid waste currently discarded in landfills.
Technical Abstract: The use of granular starch as a filler in biodegradable plastics has been widely studied. Poor adhesion between the hydrophilic starch granule surface and hydrophobic polymer matrix results in poor composite properties in most systems. The adhesion can be improved by the addition of compatibilizers, which reduce the high surface energy between the phases. Compatibilizer effects were studied in composites of starch with either low density polyethylene (LDPE) or poly(hydroxybutyrate-valerate) (PHBV). The addition of ethylene-acrylic acid copolymer to LDPE/starch composites does not increase the tensile strength or elongation, but increases the modulus, as well as torque and pressure during extrusion. The use of starch coated with poly(ethylene oxide) improves the tensile strength and elongation of PHBV/starch composites.