An antibacterial strategy on chrome-free tanned leather: based on β-cyclodextrin aldehyde derivatives and small molecule

Chrome tanning has dominated in leather production up to now, while facing a significant challenge in terms of chromium. Therefore, the chrome-free tanning process becomes an inevitable choice. However, chrome-free tanned leather (CFTL) is poor in antibacterial properties, which limits its practical application in leather production. In this work, a new environment-friendly antibacterial strategy based β-cyclodextrin (β-CD) aldehyde derivatives and ciprofloxacin hydrochloride (CH) as a small molecule model antibacterial agent was developed to address this issue along with improving the comprehensive performances of leather. The structure and properties of obtained leather were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, thermogravimetric, and its antibacterial effect against E. coli and S. aureus was investigated. The results showed that compared with CFTL without β-CD modification and CH treatment, the Ts, Td and Tp of the leather with this method possessed increased 5.7°C, 4.9°C, and 6.9°C, respectively. After being treated by CH with 90 days of storage, the antibacterial rates against E. coli and S. aureus still reached 99.8% and 97.4%, respectively, which were 29.9% and 34.4% higher than those without β-CD treatment. It, that antibacterial agent is included in the cavity of β-CD on CFTL, will improve the poor antibacterial durability due to the release of the small molecule antimicrobial agent. These findings, therefore, indicated that a new antibacterial method on CFTL with β-cyclodextrin aldehyde derivatives and ciprofloxacin hydrochloride has potential practical application prospects in leather production.