An approach towards identification of leather from leather-like polymeric material using FTIR-ATR technique

Leather, a by-product of the meat industry, has unique strength, elasticity, water vapor permeability, resistance to abrasion, durability, and longevity. In the background of ISO 15115:2019, the authenticity of leather has become a subject matter of concern. There is a need to distinguish leather (animal origin) from other leather-like materials derived from fossil fuel (PU, faux leather, etc.) and agro-product-driven vegan materials, which are also sold in the market as leather. For this purpose, this work relies on the signature FTIR bands of collagen (the skin-making protein) as a starting point to distinguish between animal origin and rest. A detailed investigation of all types of materials used in lifestyle products has been carried out to assess the boundary lines of this hypothesis. It is reasonably concluded that the signature Amide I, II, and III bands of collagen occurring at 1600, 1500, and 1200 cm⁻¹ could serve as the first line to distinguish against all materials other than nylon and in the case of nylon, and the Amide A band at 3200 cm⁻¹, forms the basis for differentiation from nylon. In essence, the FTIR spectra can be used as a robust, easy and unambiguous technique to distinguish leather from leather-like materials currently available on the market.

Graphical Abstract