Aging Studies on Food Packaging Films Containing β-Cyclodextrin-Grafted TiO₂ Nanoparticles

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Polymeric materials like polyvinyl alcohol (PVA) and ethylene-PVA copolymers (EVOH) are crucial in food packaging due to their beneficial properties.
• Titanium dioxide (TiO2) nanoparticles (NPs) offer potential bactericidal effects but may also accelerate nanocomposite degradation.
• Derivatizing TiO2 NPs with cyclodextrins (CDs) can enhance food preservation by enabling them to act as carriers.

Purpose of the Study:

• To prepare and evaluate films made from PVA or EVOH incorporating β-Cyclodextrin (βCD)-grafted TiO2 nanoparticles.
• To assess the accelerated aging and degradation behavior of these nanocomposite films under various environmental conditions.
• To understand the influence of TiO2 NPs and CDs on the stability and properties of PVA and EVOH packaging materials.

Main Methods:

• Preparation of PVA and EVOH films containing βCD-grafted TiO2 nanoparticles.
• Accelerated aging tests using a stability chamber (varying temperature and relative humidity) and UV light irradiation.
• Analysis of film degradation through color change measurements (CIELAB) and Fourier transform infrared (FTIR) spectroscopy.

Main Results:

• Film degradation was more pronounced with increasing temperature (25-80 °C) and relative humidity (28-80%), with no significant effect from cyclodextrins.
• UV light irradiation caused greater color variation in nanocomposite films, especially with higher TiO2 NP concentrations (1-5%), due to photocatalysis.
• FTIR analysis indicated increased material degradation in the presence of TiO2 NPs, evidenced by changes in signal intensities.

Conclusions:

• The presence of TiO2 nanoparticles significantly enhances the degradation of PVA and EVOH films under accelerated aging conditions, particularly UV exposure.
• While CDs did not influence degradation, the photocatalytic activity of TiO2 NPs is a key factor in the observed changes.
• These findings are crucial for optimizing the use of TiO2-based nanocomposites in food packaging, balancing functionality with long-term stability.