Improved leather properties through ultrasonically-produced hydroxyapatite/β-cyclodextrin composites

One of the main problems associated with the tanning industry is that significant amounts of hazardous substances are released into the environment causing problems for the ecosystem and human health. The development of non-toxic and biodegradable additives that guarantee the quality performance of durable and functional leather without contaminating the environment is therefore crucial. In this work, ultrasound, a green and clean technology, was used for the synthesis of β-cyclodextrins/hydroxyapatite-based composites to improve the leather quality. The use of ultrasound to reduce the size of the hydroxyapatite particles (sono-deagglomeration) was found to be effective, as was the use of cyclodextrin to increase the stability and solubility of the nano-HAp particles. The composites were chemically and structurally characterised by ATR-FTIR, TG/DTG, XRD and SEM analyses and showed antibacterial activity and no cytotoxicity. The interaction of the composites with collagen was demonstrated by MHT method, micro-DSC and SEM. The best composite was tested on a pilot scale, showing improved leather properties compared to commercial products in terms of colour brightness, colour fastness, grain fullness, thickness, thermal stability, and breathability. This sustainable approach is attractive as it demonstrates the value of composites as safe and sustainable tanning additives.