AN ACOUSTIC-EMISSION STUDY OF STAKING AND FATLIQUOR

The chemical treatment of leather with fatliquor and the physical trea tment of staking produce similar esthetic results. The effects of two such different treatments on the structure of the leather, however, an d perhaps various other responses to deformation, are expected to be d ifferent. The equivalence of fatliquoring and stalking were investigat ed by comparing the effects of the treatments on the stress-strain cur ves and the acoustic emission observed during tensile testing. It was found that staking affects only the first 25% of the elongation at bre ak, lowering the initial modulus, while fatliquor affects the whole st ress-strain curve. The initial part becomes concave upward instead of downward, and the elongation and stress at failure are greater. Acoust ic emission from leather that was merely staked was suppressed only at small elongations, while it was smaller at all elongations from leath er that had fatliquor. The results are shown to be consistent with a d omain model of deformation. A nondestructive determination of the elon gation of leather at tensile failure, based on acoustic emission, is d erived from the observations.