Structural and thermal properties of vegetable tanned leather with the addition of zeolite

Tanning plays the most important role in leather durability, stabilizing the triple helical structure of the collagen. It has been proven that the strength of the resulting bonds depends on the type of tanning agent. Today, mineral tanning is particularly popular due to tanning results. However, vegetable tanning is still used for certain purposes due to the environmental aspect. Mechanism of their stabilization is based on multi hydrogen links between the polyphenols and collagen. In recent years, synthetic zeolite has been used in “wet white” pretanning and pretanned leather exhibiting better properties than other “wet white” pretanning methods. Subsequent tanning processes makes it possible to manufacture leather with different properties and characteristics. The tanning properties of synthetic zeolites and their effectiveness in the exhaustion of chrome tanning float have been previously investigated. Combined use of zeolite and chrome results in both higher float exhaustion and higher shrinkage temperatures in shorter time than in conventional chrome tanning. In this paper, the possibility of tanning beef leather using vegetable tanning with the addition of zeolite was investigated. The analysis of physicochemical properties of samples was performed using Fourier transform infrared (FT-IR) spectroscopy. The samples were subjected to thermogravimetric analysis (TGA) with the aim of monitoring the thermal stability of the tanned bovine leather sample. The samples thus prepared were also tested for flex resistance by the flexometer method according to HRN EN ISO 5402-1:2017 and for water vapor permeability according to HRN EN ISO 14268:2012, and the distension and surface strength of the samples were determined according to HRN EN ISO 3379:2015.