Development of linseed oil-TiO₂ green nanocomposites as antimicrobial coatings

This study deals with the preparation and characterization of acrylated epoxidized linseed oil (AELO) based bionanocomposites for antimicrobial coating applications. AELO was synthesized from epoxidized vegetable oils, crosslinked with an acrylic monomer, reinforced with anatase TiO₂ nanoparticles and then subjected to UV irradiation to yield the cured nanocomposite coatings. The effect of TiO₂ loading on the morphology, barrier, thermal, mechanical, tribological and antibacterial performance of the coatings has been comprehensively investigated. FT-IR spectra indicated the existence of strong TiO₂-AELO hydrogen bonding interactions. The nanoparticles were randomly dispersed within the bioresin, significantly reducing its water absorption and gas permeability whilst increasing its thermal stability. They also promoted remarkable enhancements of both static and dynamic mechanical properties such as storage and Young's moduli, hardness, impact resistance and glass transition temperature. Strong reductions in the coefficient of friction and the wear rate were attained in the nanocomposites with the highest TiO₂ loadings. The coatings were found to display antimicrobial activity even in the absence of UV light, and the bactericidal effect against Staphylococcus aureus was higher than on Escherichia coli. Furthermore, the antimicrobial activity improved with increasing nanoparticle concentration. The use of these "green" nanocomposite coatings could be a suitable and inexpensive method to prevent microbial proliferation in public places, particularly in medical centers where there is higher risk of infections.