Measurement of shrinkage behaviour in leather and parchment by dynamic mechanical thermal analysis

The mechanical behaviour of modem and historic parchment and leather sample s through their shrinkage temperature is described. The measurements are ma de possible by the novel modification of a standard dynamic mechanical ther mal analyser (Rheometric Scientific DMTA Mk3) to enable experiments to be c onducted on samples immersed in water. A sample of parchment was clamped in tensile mode under a small static applied force. The temperature of the wa ter could be controlled and thus it was possible to heat the sample and mon itor the change in its displacement as it passed through the shrinkage temp erature. Information could therefore be obtained on the percentage shrinkag e and the temperature range over which it occurred. Furthermore, the method also provided useful information on the expansion or contraction of the sa mples on initial immersion in water, which relates to ease of sample wettab ility, and on the changes during drying process and rehydration. (C) 2000 E lsevier Science B.V. All rights reserved.