Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2009
Publication Date: 6/19/2009
Citation: Selling, G.W., Shogren, R.L. 2009. Production of PLA-Starch Fibers. Meeting Abstract. Abstract #54.
Technical Abstract: Composites of polylactic acid (PLA) with starch have been prepared previously in an effort to reduce cost as well as to modify other properties such as biodegradation rate. However, strength and elongation both decrease on addition of starch due to poor adhesion and stress concentration at the interface. Mechanical properties can be restored by addition of cross-linking agents such as MDI or peroxides/maleic anhydride but these reagents are rather toxic. Although it is well known that orientation greatly improves the mechanical properties of PLA and starch, there has been little previous work of the effect of orientation on the mechanical properties of PLA/starch composites. In this research, PLA/starch fibers were produced by twin screw extrusion of PLA with granular or gelatinized starch/glycerol followed by drawing through a set of winders with an intermediate oven. At 30% starch, fibers drawn 2-5x were highly flexible (elongation 50-100%) while undrawn filaments were very brittle (elongation < 3%). Tensile strength and modulus increased with increasing draw ratio and annealing temperature but decreased with increasing starch content. Mechanical properties were better for composites made with gelatinized starch/glycerol than granular starch. In conclusion, orientation greatly increases the flexibility of PLA/starch composites and this may be useful not only in fibers but also possibly in molded articles. Other advantages of starch addition could include fiber softness without added plasticizer, fiber absorbancy for moisture and odors.