Relaxation behavior of collagen.

The dynamic mechanical properties of purified collagen from bovine tendon were studied using a torsion pendulum in the temperature range of 120 degrees -360 degrees K at 0.3-1 cps. In the temperature range studied, two loss peaks were observed: a beta-peak at about 200 degrees K, and an alpha-peak approximately five times larger at about 280 degrees K. The temperature of the alpha-transition is shown to be dependent on water content, decreasing with increasing amount of water and shifting to lower temperatures. Broad-line proton magnetic resonance results were also obtained on similar samples. A narrow nuclear magnetic resonance (NMR) line appears at about 250 degrees C. The effects of shrinkage to form gelatin and of cross-linking on the relaxation behavior of collagen were also studied. The motions taking place in collagen over the 120 degrees -360 degrees K range are discussed.