Technological watch

Effects of the geometry of reinforcement on physical properties of sodium caseinate/TiO2 nanocomposite films for applications in food packaging

Plastic materials for food packaging are being replaced by biodegradable films based on biopolymers due to the adverse effects they have had on animal life and the environment. In this study, nanocomposite films containing 2.5 wt% sodium caseinate and 2 wt% glycerol were reinforced with 0.1 or 0.2 wt% nano TiO2 prepared in two forms: spheres (P25) and tubes. The effects of nanoreinforcement geometry on mechanical, tensile, barrier, thermogravimetric, and optical properties, and distribution of nanoparticles were described. The interactions among film components were analyzed by Fourier transform infrared spectroscopy (FTIR). Addition of nanotubes significantly increased E' (341?wt%) and E" (395?wt%) moduli, the Young modulus E (660?wt%), the residual mass at 500°C (38?wt%), and color change (6.78) compared to control film. The compositional mapping studies showed that P25 nanoparticles were homogeneously distributed between the surfaces of the film while nanotubes were found on the bottom surface. The changes in position of the FTIR spectra signals as compared to pure protein signals indicated strong matrix/reinforcement interactions. In addition, the changes in intensity in 1100, 1033, and 1638?cm?1 FTIR signals suggested formation of a protein/Tween 20 ester. The geometry of reinforcement was highly relevant regarding physical properties, showing nanotubes as being very successful for enhancing tensile properties.

Publication date: 11/02/2023



This project has received funding from the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 837761.