Synthesis, characterization, and biodegradability of fatty-acid esters of amylose and starch

A series of starch and amylose esters with different degrees of substitutio n and side-chain length were prepared and studied. The esters were prepared by acylation of the polysaccharide with the appropriate acid chlorides, su ch as octanoic, dodecanoic, and octadecanoic. The degrees of substitution w ere 0.54, 1.8, and 2.7. After preparation, the resulting esters were charac terized by elemental analysis, H-1 nuclear magnetic resonance (H-1-NMR), Fo urier transform infrared (FTIR), differential scanning (DSC), thermogravime tric analysis (TC;A), contact angle, and water uptake; measurements. Their mechanical properties and, in particular, the tensile strength and elongati on at break depend on the side-chain length and on the deg-ree of substitut ion. The extent of their biodegradability, after exposure to activated slud ge, was assessed by weight loss measurements and scanning electron microsco py (SEM). It; was found that these new materials are biodegradable, and the biodegradation rate decreases with increasing degree of esterification. (C ) 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1440-1451, 1999.