| Abstract: | Mixtures of high‐amylose corn starch and oleic acid were processed by steam jet cooking, and the dispersions were rapidly cooled to yield amylose–oleic acid inclusion complexes as micron‐ and submicron‐sized spherulites and spherulite aggregates. Dispersions of these spherulite particles were then graft polymerized with methyl acrylate, both before and after removal of uncomplexed amylopectin by water washing. For comparison, granular, uncooked high‐amylose corn starch was also graft polymerized in a similar manner. Graft copolymers with similar percentages of grafted and ungrafted poly(methyl acrylate) (PMA) were obtained from these polymerizations. The graft copolymers were then processed by extrusion through a ribbon die, and the tensile properties of the extruded ribbons were determined. Although extruded ribbons with similar tensile strengths were obtained from the three starch–PMA graft copolymers, much higher values for % elongation were obtained from the spherulite‐containing systems. Also, the tensile properties were not significantly affected by removal of soluble, uncomplexed amylopectin by water washing before graft polymerization. These results are consistent with the observation that these PMA‐grafted starch particles did not melt during extrusion, and that continuous plastic ribbons were formed by fusing these particles together in the presence of small amounts of thermoplastic PMA matrix. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40381. |
