# Thermal, Mechanical, and Barrier Properties of PHBV Nanocomposites via TiO2 Incorporation for Sustainable Food Packaging

## TL;DR

This study examines how adding TiO2 nanoparticles affects the properties of PHBV for food packaging, finding that small amounts improve some traits but higher amounts reduce performance.

## Contribution

The novelty lies in evaluating the impact of TiO2 content on PHBV's thermal, mechanical, and barrier properties for sustainable packaging.

## Key findings

- Low TiO2 content (1% and 3%) improves thermal stability and barrier properties of PHBV.
- Higher TiO2 content (7%) increases biodegradation but reduces mechanical strength and modulus.
- Nanocomposite properties generally deteriorate with increasing TiO2 loading.

## Abstract

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biodegradable polyester considered for food packaging, though its mechanical and barrier limitations pose challenges. This study assessed PHBV/TiO2 nanocomposites for packaging applications. Differential scanning calorimetry revealed reduced crystallinity and lower melting points with an increase in TiO2 content. Thermal stability improved at 1% and 3% TiO2, raising onset temperatures to 283 °C and 284 °C, respectively. Scanning electron microscopy and FTIR confirmed uniform nanoparticle dispersion without agglomeration. Tensile tests showed decreasing strength and modulus from 1% to 7% TiO2, with peak elongation at 3%, whereas viscosity behavior declined with higher nanoparticle loading. Low portions of nanoparticles (1% and 3%) induced the improvement in barrier properties against oxygen and water vapor. The highest biodegradation rate occurred at 7% TiO2. Overall, the nanocomposites’ properties tend to deteriorate with the addition of higher portions of TiO2. Thus, despite some improvements, the nanocomposites did not deliver consistent, multi-property enhancements to justify use in food packaging. Key metrics like sealability and appearance were not evaluated. Future research should explore surface-treated TiO2, alternative fillers, compatibilizers, and optimized processing, alongside standardized safety assessments for food-contact applications.