Preliminary studies on the surface layer of starch

Characterization of the surface layer of starch powder, originated from potato or maize, was carried out applying various experimental techniques: Fourier‐transformed infrared internal reflection spectroscopy (FTIR‐IRS), inverse gas chromatography (IGC) and scanning electron microscopy (SEM). The main kinds of starch were studied as potential fillers for rubber and results discussed in terms of factors requiring modification to improve starch miscibility and activity towards rubber. Starch of high amylopectine content shows surface enrichment with amylose what makes crystallinity of the surface layer higher than in bulk of the material. Particles of the both kinds of starch have very smooth surface (morphological index, I m = 0.995), highly resistant to its geometrical development. Dispersive component of the surface energy of starch was found to be similar to that of low energy polymers (γ s d = 32.5 m J/m 2 at 23°C) and its surface to be of electron‐donor character.