The Effects of Glycerol Addition on Mechanical Properties of Thermoplastic Films Based on Mango Seed Starch

Abstract

The aimed of the present work is to examine the effects of glycerol as plasticizer incorporated with mango seed starch. The fabrication of films involved mixing between the fixed amount of mango seed starch (3 wt. %) with various amount of glycerol ranges from 5 to 30 wt. %  through solution casting method. From the analysis, the tensile strength of films decreases with increasing glycerol content from 5 to 30 wt. %. This can be correlated to the presence of free volume or voids in the films as indicated by scanning electron microscope. Contrarily, the films’ elongation at break increases with increasing glycerol content  from 5 to 25 wt. %. The findings are corroborated with the Fourier transform infrared spectra, in which the hydrogen bond formation was observed. However, the elongation of film is significantly reduced when glycerol content increased from 25 to 30 wt. % due to the anti-plasticization phenomenon by highly plasticized starch. Therefore, the variance of glycerol content in mango seed starch demonstrates a significant effect on the mechanical properties of fabricated films.