Polymer and Materials Science
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
A new method is presented which permits the quantitative characterization of interfilament friction of staple yarns using loss tangent tanδ data measured directly from samples nondestructively with the Rheovibron DDV-II viscoelastometer. The procedure is derived from a phenomenological model of the structure's mechanical behavior in which its energy dissipation capacity consists of both filament internal viscous friction and a filament-to-filament coulomb friction mechanism. By treating the coulomb dissipation in terms of an additional effective viscous component, the loss tangent of the model representing the structure can be analytically expressed in terms of the internal filament viscous properties, a fiber-to-fiber coulomb parameter, and an undetermined assembly dispersion factor which is representative of strength. By measuring effective loss tangent data for the staple yarn and a constituent filament at two separate frequencies and considering the magnitude of the coulomb mechanism to be independent of the test frequency in the range employed, both the coulomb friction dissipation and the assembly dispersion factor can be quantified. Using this procedure, loss tangent data from tests on a series of staple yarns (nylon, polyester, and acrylic fiber) are used to calculate both assembly dispersion and interfilament coulomb friction factors.
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