Abstract

ATR Spectroscopy has been used to follow in situ, the penetration of surface active agent solutions into a water repellent porous system (leather). Penetration rates can be compared by measurements of the reflection optical density (E) of water as a function of leather sample thickness (l). The proposed quantitative rate criterion is the slope of the linear E-l plot, whilst the amount of absorbed water is expressed by the value of E at a fixed sample l value. Deviations from the E-l relationship provide a guide to the irregularity of distribution and fixation of the water repelling agent in the leather. The method requires the use of a simple optical penetration cell placed in the ATR unit of an infra red spectrophotometer. The method would allow fast and simple control of waterproofing of either finished or part processed leathers.