Surface chemical functionalization of starch nanocrystals modified by 3-aminopropyl triethoxysilane

A comparative experiment about the 3‑aminopropyl triethoxysilane (APTES) modification of waxy potato starch nanocrystals (WPSNCs) and waxy maize starch nanocrystals (WMSNCs) was employed in the present study. The purpose of surface chemical functionalization was to introduce functional groups and improve hydrophobicity of SNCs for the extensive application. The degree of substitution (DS) of both SNCs displayed the upward trend with the increase of applied APTES, while WPSNCs showed higher DS than that of WMSNCs in the same dosage of APTES. XRD revealed the un-changed crystalline structure and decreased relative crystallinity after the modifications. The structure of silylated SNCs surface was characterized by FT-IR and XPS, which confirmed the presence of functional amino groups. The introduction of amino groups resulted in a simultaneous enhancement of zeta potentials for both SNCs relatively. The modified SNCs could be uniformly dispersed both in water and ethanol phase revealing improved hydrophobicity through wettability experiments.