Preparation and Characterization of Polymer Composite Materials Based on PLA/TiO2 for Antibacterial Packaging

Abstract

Polymer composite materials based on polylactic acid (PLA) filled with titanium dioxide (TiO2) nanoparticles were prepared. The aim of this work was to investigate the antibacterial action of TiO2 against a strain of E. Coli (DH5α) to obtain information on their potential uses in food and agro-alimentary industry. PLA/TiO2 systems were prepared by a two-step process: Solvent casting followed by a hot-pressing step. Characterization was done as a function of particle size (21 nm and < 100 nm) and particle content (0%, 1%, 5%, 10%, and 20%, wt %). Structural characterization carried out by X-ray diffraction (XRD) and Fourier Transformed Infrared spectroscopy (FTIR) did not reveal significant changes in polymer structure due to the presence of TiO2 nanoparticles. Thermal characterization indicated that thermal transitions, measured by differential scanning calorimetry (DSC), did not vary, irrespective of size or content, whereas thermogravimetric analysis (TGA) revealed a slight increase in the temperature of degradation with particle content. Bacterial growth and biofilm formation on the surface of the composites against DH5α Escherichia Coli was studied. Results suggested that the presence of TiO2 nanoparticles decreases the amount of extracellular polymeric substance (EPS) and limits bacterial growth. The inhibition distances estimated with the Kirby-Bauer were doubled when 1% TiO2 nanoparticles were introduced in PLA, though no significant differences were obtained for higher contents in TiO2 NPs.

Bacteria Exposed to Silver Nanoparticles Synthesized by Laser Ablation in Water: Modelling E. coli Growth and Inactivation

“…DH5α is commonly used laboratory E. coli strain to maintain and amplify small plasmid DNA [43]. More importantly, it is often used in fundamental research of a wide range of new potential antibacterials [44][45][46][47] and even for the production of silver nanoparticles upon transformation [48]. Additionally, it seemed reasonable to model growth curves of this strain since we have thoroughly investigated its growth parameters [40].…”

Manufacturing and Characterization of Functionalized Aliphatic Polyester from Poly(lactic acid) with Halloysite Nanotubes

“…These environmentally friendly polymers could be classified into three different groups with different environmental connotations [8]. One group is composed of biodegradable petroleum-derived polymers such as most aliphatic polyesters, i.e., poly(ε-caprolactone)—PCL, poly(butylene succinate)—PBS, poly(glycolic acid)—PGA and so on [9,10,11]. Although they are petroleum-derived polymers, they show interest from an environmental standpoint as they can be disintegrated in controlled compost soil conditions.…”

Flexible electrospun PET/TiO2 nanofibrous structures: Morphology, thermal and mechanical properties

“…Furthermore, the value of the residual amount at 600°C also increased for all PET/TiO 2 nanocomposite fibers compared to the neat PET fiber, which confirms the presence of inorganic materials in the nanocomposite. Previous studies have also shown a slightly increase in thermal stability of the polymer matrix when metal oxide nanoparticles are incorporated …”