The research subject was the analysis of the microstructure, barrier properties, and mechanical
resistance of the psyllium husk (PH)-modified thermoplastic starch films. The tensile tests
under various static loading conditions were not performed by researchers for this type of material
before and are essential for a more precise assessment of the material’s behavior under the conditions
of its subsequent use. The film samples were manufactured by the casting method. PH addition
improved starch gelatinization and caused a decrease in failure strain by 86% and an increase in
failure stress by 48% compared to pure films. Fourier transform infrared spectroscopy results showed
the formation of additional hydrogen bonds between polysaccharides in starch and PH. An increase
in the number of hydrophilic groups in the modified films resulted in a faster contact angle decrease
(27.4% compared to 12.8% for pure ones within the first 5 s); however, it increased the energy of water
binding and surface complexity. The modified films showed the opacity at 600 nm, 43% higher than
in the pure starch film, and lower transmittance, suggesting effectively improving barrier properties
to UV light, a potent lipid-oxidizing agent in food systems.