MATRIX MACROMOLECULES THAT AFFECT THE VISCOELASTICITY OF CALFSKIN

The chemical basis of viscoelasticity of bovine skin was explored by m echanical relaxation spectroscopy after selective enzymatic degradatio n. Measurements covered a wide range of time scales because water was replaced in the tissue with aqueous mixtures of ethylene glycol, which maintained a water-like electrical environment for the charged macrom olecules down to -50-degrees-C. Macromolecular components that couple the fibrils to the interfibrillar matrix contribute about half the val ues of the resultant storage and loss moduli, while removal of compone nts that are readily extractable, so perhaps free in the matrix, did n ot alter these mechanical quantities or their relaxations. The precisi on of the method reveals the effects of fibril-attached matrix, when c onventional methods of mechanical testing fail.