UBC Theses and Dissertations
The effect of temperature and humidity on the mechanical properties of textile fibres Price, Stanley James Whitworth
Forced vibrational experiments and stress relaxation experiments have been performed on acetate rayon, viscose rayon, nylon, and polyethylene over a range of humidities at both 2°C and 25°C. Forced vibrational experiments have also been carried out on acetate rayon, viscose rayon, and raw silk over the temperature range -80°C to 0°C. Interpretation of previous experiments is discussed in terms of both Newtonian viscosity and Eyring viscosity. The apparatus employed is described and a method for calibrating the solenoid of the forced vibrator is outlined. An inverse relation has been found between ηω and the negative slope of the stress relaxation curve, E°. Since the equation ηω = π/(4.606) E° derived on the basis of Newtonian viscous units predicts a direct relation between ηω and the slope E°, it is assumed that the flow in stress relaxation must be non-Newtonian* Preliminary calculations indicate that a more satisfactory relation between ηω and E° may exist if the flow units involved in stress relaxation follow the Eyring law of viscous flow. An outline for determining such a relation is given. The experimental 1y observed increase with decreasing temperature of dynamic modulus, stress relaxation modulus, and energy loss, as measured by ηω, is interpreted in terms of increasing order of chain segments. A maximum found at -55°C in the ηω vs. temperature curve for viscose rayon is attributed to a "freezing in" of segment motions as the result of a second order transition.
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