Curcumin as a natural compound in the synthesis of rigid polyurethane foams with enhanced mechanical, antibacterial and anti-ageing properties

Abstract

This paper presents the effect of natural compound (E,E)-1,7-bis(4-Hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (curcumin) on the antibacterial, anti-aging, mechanical and morphological properties of polyurethane (PU) rigid foams. Concentrations of 1 wt%, 2 wt% and 5 wt% of antibacterial compound was used, and the infection reduction capacity was evaluated for different types of bacteria (Escherichia coli (G-) and Staphylococcus aureus (G+). In order to determine all assumed properties the synthesized PU foams were characterized by analytical (Fourier Transform Infrared Spectroscopy, FTR), morphological (Scanning Electron Microscopy, SEM), bactericidal effects (Disc Diffusion Method), thermal characteristic (Thermogravimetric Analysis, TGA), mechanical techniques (three-point bending test and compressive test) and physical properties (apparent density, dimensional stability, contact angle, water uptake, color characteristics). Compared to the reference foam, compositions modified with 1 and 2 wt% of the curcumin showed greater compressive strength (increase of 10 and 7%, respectively), higher flexural strength (increase of 17 and 7%, respectively), less water uptake (decrease by 12 and 10%, respectively), as well as, better thermal properties. On the other hand, it has been shown, that in all cases, curcumin can be used as a natural anti-ageing additive for polymers. The addition of curcumin in the amount of 1, 2 and 5 wt% considerably improved the stabilization of the polymer. Moreover, based on the microbiological results, it has been shown that the addition of 5 wt% of the extract is suitable for the manufacturing of PU foams with enhanced antibacterial properties.