Reuse of leather shavings as a reinforcing filler for poly (vinyl alcohol)

Leather shavings, the by-products of leather industry, are usually treated by the landfill, which probably makes them hazardous to the human health and the environment due to the oxidation of the containing chromium (Cr) (III) to toxic Cr (VI). Therefore, efficient and environment-friendly reusing of leather shavings is not only of great interest but is also a huge challenge. This article reported a reuse method of leather shavings by combing two novel technologies, that is, the solid state shear milling (S 3 M) to mechanochemically pulverize and activate leather shavings, and the thermal processing of poly (vinyl alcohol) (PVA) to make them filled with PVA. The related mechanism, the structure, and properties of the obtained composites were investigated. The results showed that S 3 M method could efficiently pulverize and activate leather shavings through very strong shearing and compressing forces, promoting the formation of more hydrogen bonds and the chelation in the interfaces between PVA and leather shavings, and consequently enhancing their compatibility. In this way, PVA/leather shaving composites with pretty good performances, for example, better mechanical properties, thermal stability, and water resistance as compared with neat PVA, were obtained. This is a convenient, cost-efficient, and environment-friendly technology to recycle hazardous chrome-containing leather shavings.