Abstract

During manufacture the structure and properties of a rawhide are changed by the addition of auxiliaries. Efficient control of these processes requires difficult analytical work. In this work, the FTIR-spectroscopy by attenuated total reflection (ATR) was used to analyse the changes in the natural matrix of the raw cow hide during tanning and finishing.

To obtain reliable results and to minimise errors caused by the inhomogenity of samples, five pairs of samples were cut from the treated hide after every step of the process. Because of result scatter spectrum averaging was used to process the results.

The averaged spectra were subtracted either from the spectrum of a raw hide (standard), or from the spectrum of the sample prepared in an earlier stage. The differential table obtained was correlated to known data.

It was possible from the spectra (except for that of limed hide) to determine changes in constitution of the hide as well as constituents added to the collagen matrix.

Absorption bands of carbonyls, sulphate anion, sulphonates, silicones and nitro-compounds, as well as the C-H bending of the alkyl chains of added auxiliaries allow identification of the process step and deter mination of the content of added agents, as well.

The simplicity of the method and results obtained make it very useful as a method for QC and QA in tanning processes.