It has been shown that the immersion of wool fibers in solutions capable of denaturing proteins causes either a decrease in the elastic modulus of the Hookean region of the stress-strain diagram or the complete disappearance of this region and a small but significant decrease in stiffness of the fiber in the post-yield region. The strain at the turnover point between yield and post-yield regions and the breaking strain are unaffected by these reagents unless the fibers supercontract during equilibration with the solyent. A decrease in the extension at this turnover point is then observed. The results are used in a critical assessment of various structural models proposed for the wool fiber.
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