Photocatalytic inhibition of bacteria by TiO2nanotubes-dopedpolyethylene composites

Abstract

Polyethylene (PE) and polyethylene-octadecene (LLDPE) composites containing titanium dioxide nano-tubes were synthesized and applied to the inhibition of selected bacteria. It was found that polymerizationrate of the polymerizations increased with the incorporation of the octadecene compared withbare ethylene, while with modified nanotubes (O–TiO2–Ntbs) the catalytic activity showed a slightdecrease compared with the pure polymer. Regarding physical properties, the melting temperature andcristallinity of PE was higher than LLDPE. LLDPE presented lower rigidity than PE and thus lower Young’smodulus. On the other hand, with the incorporation of nanotubes, Young’s modulus did not change sig-nificantly with respect to PE. After 2 h of contact, the PE/O–TiO2–Ntbs composite showed a reductionof Escherichia coli of 36.7% under no UVA irradiations. In contrast, LLDPE/O–TiO2–Ntbs showed 63.5%.The photocatalytic reduction (under UVA light) was much higher and after 60 min the LLDPE/O-TiO2-Ntbs composites showed a bacterial reduction of 99.9%, whereas the PE/O-TiO2-Ntbs showed 42.6% ofcatalytic reduction.