Biodegradable blends of poly(<scp>L</scp>‐lactide) and starch

Abstract

Abstract Blends of poly( L ‐lactide) (PLA), containing from 5, 15, or 25 wt % potato starch, unmodified or hydrophobized in methane plasma, were prepared and studied. To enhance the drawability of the blends, the plasticization of PLA with 10 wt % poly (ethylene glycol) (PEG) was also employed. The thermal and mechanical properties of the blends with amorphous and crystalline matrices were investigated. The hydrophobization of starch did not improve the ultimate properties of the blends, which were generally worse than those of neat PLA, because of the separation of the starch grains from the polymer matrix during tensile drawing. The separation also occurred in blends with a PEG‐plasticized matrix containing 15 wt % modified starch, which fractured earlier than PLA plasticized with PEG. Nevertheless, the elongation at break of the plasticized blends reached 1.3, which was considerably more than that of blends with corresponding starch contents without a plasticizer (ca. 0.05). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 269–277, 2007