Infrared spectroscopy, mechanical analysis, dielectric properties and microwave response of pigskin gelatin films plasticized withglycerol

Some physical and structural properties of gelatin films were studied as a function of glycerol content, focusing on the interactions between the glycerol, film structure and the moisture content. Fourier transform infrared spectroscopy was used to study the changes of the main functional groups of the film. The displacement in the amide's position occurred with lower plasticizer content, possible due to the predominance of bound water in the film matrix. The glycerol increased the flexibility of the films, as determined by the measurements of tensile strength, elongation and elastic modulus. Finally, microwave reflected signal measurements and dielectric constant measurements were also found to be sensitive to glycerol content, presumably due to its hydrophilic nature.

► This paper analyzes gelatin films with different glycerol contents. ► A microwave method is used to study the glycerol and moisture effects in the films. ► The way water interacts with the film structure is reported in this paper.