Enhancing the Characteristics of Starch‐Based Films With Hydrophilic and Hydrophobic Carbon Black

ABSTRACT This study aimed to improve the properties of starch‐based films by incorporating hydrophilic and hydrophobic carbon black (CB) at varying concentrations. The apparent viscosity of the film‐forming dispersions increased with the addition of CB. Morphological analysis revealed that hydrophilic CB exhibited better dispersion within the film matrix compared to hydrophobic CB. However, the presence of CB agglomerations led to an increased friction coefficient of the film. Fourier transform infrared (FTIR) spectroscopy indicated that interactions existed between the CB and the starch matrix, with hydrophilic CB enhancing these interactions. As the CB content increased, both the glass transition temperature (Tg) and puncture resistance increased. The starch‐based films containing CB demonstrated low UV‐Vis light transmittance. The tensile strength increased from 1.26 to 7.51 MPa as the hydrophilic CB content increased from 0% to 40%. The presence of CB reduced the water vapor permeability from 9.07 × 10 −13 g −1 s −1 Pa −1 to 5.10 × 10 −13 g −1 s −1 Pa −1 , while the water contact angle increased from 37.50° to 61.83°. Additionally, the water solubility index and moisture content decreased with increasing CB content. The results suggested that CB enhanced the mechanical and water resistance properties of the starch‐based films.