

@mastersthesis {6217,
	title = {{ASPECTS} {OF} {THE} {DYNAMIC} {PROPERTIES} {OF} {KERATIN} {FIBRES}},
	year = {1984},
	note = {0558011},
	school = {University of New South Wales (Australia)},
	type = {phdPh.{D}.},
	address = {Ann Arbor},
	abstract = {Wool belongs to a class of proteins called keratins which are known for their high extensibility. From x-ray diffraction experiments this property has been attributed to the unfolding of one semi-crystalline molecular structure ((alpha)-keratin) into another ((beta)-keratin). A dynamic mechanical tester which measures the complex modulus of a fibre as a continuous function of extension in different temperature and humidity environments has been modified, improved and used to examine the (alpha) ({\textless}{\textendash}-{\textgreater}) (beta) transformation under different conditions. The improvements included techniques to eliminate noise, updating the apparatus with more precise equipment and extending its capacity to be used in a variety of viscoelastic applications, adaption of the conditioning chamber to accommodate a rapid change of environmental fluid and a re-evaluation of the limits of validity of the data in view of new experimental conditions. The dynamic modulus of wet and dry wool were measured (at 116 Hz., 25(DEGREES)C.) in the Hookean and Yield regions and compared by viscoelastic transformation with published results obtained on a different time scale. Wool, in the Hookean region, is linear viscoelastic up to about 1\% strain; beyond that, non-linear phenomena prevail, and a non-linear mechanism is proposed which explains the change in dynamic modulus with extension in terms of a stress transfer from the microfibrils to the thixotropic matrix. The mechanism enables calculation of dynamic moduli for the different components of a wool fibre during extension. Measurement of the dynamic modulus in wool fibres set in boiling water at 10\% strain for different time periods shows progressive damage to the crystalline microfibrillar portion of the fibre with time, but very little modification to the amorphous matrix. The dynamic modulus of wool was measured in aqueous HC1 at pH1 and in the presence of alcohols. Water does not interfere with the microfibrils, but acid and the alcohols do interact with these ordered structures. HC1 weakens the microfibrils by about 50\%. These plasticizers wash out without leaving any measureable change. Their influence on the matrix is, also, one of weakening, which depends upon the particular plasticizer or combination of plasticizers in use.},
	keywords = {0994:Textile research, Applied sciences, Textile research},
	url = {http://search.proquest.com/docview/303314631?accountid=14270},
	author = {DUBRO, DENNIS WAYNE}
}
