Preparation and characterization of organic-soluble acetylated starch nanocrystals

Efficient procedures for the preparation of organic-soluble starch nanocrystal (SN) derivatives have been established with different degrees of substitution (DS). The resulting acetylated starch nanocrystals exhibit much improved solubility in common organic solvents such as N,N-dimethylformamide, acetone, carbon tetrachloride and toluene. The obtained nanocrystals were characterized by means of the FT-IR, 1H NMR and X-ray photoelectron spectroscopic techniques. When compared with the hydrophobic performance of the unmodified starch nanocrystals, that of acetylated starch nanocrystals significantly increased according to the contact angle measurement results. X-ray diffraction reveals that the crystalline structure of acetylated starch nanocrystals was changed from style A to style V. The platelet-like starch nanocrystals become sphere-shaped after modification and the size increases compared to the ungrafted particles as revealed by transmission electron microscopic results. They are versatile precursors to nanoparticle-based copolymers, composites, and metal ligands.