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The influence of water sorption on the dynamic mechanical properties of nylon 6-6 and the plasticising effect of water.

University of British Columbia

Much work has recently been done on studies of mechanical and electrical dispersion phenomena in polymers. Many workers have been active studying the effect of plasticisers, irradiation, heat, and mechanical treatment, copolymerisation, and cross-linking, such as vulcanisation, on a large number of high polymers. In spite of its great technological importance, the effect of humidity on the mechanical properties of textile fibres has not been studied in a systematic way. The present investigation is an attempt at studying the influence of humidity on the modulus and energy dissipation of nylon 6-6 monofilaments. The modulus and energy loss were determined using a low-frequency vibrometer, over the full range of relative humidities at 9, 35, and 60 °C., using 15 denier nylon monofilaments. Values of these empirical quantities were plotted as functions of frequency and humidity, and water content. The results were discussed taking into account the fact that water sorbed by fibres is present predominantly in the amorphous regions, and might be expected to break hydrogen bonds existing between adjacent peptide links, thereby reducing molecular interaction, and facilitating segmental motion. A mechanism was proposed in order to explain the results. The values of the tangent of the loss angle were compared with recent work by Sauer at al. Using expressions derived by Ferry and coworkers, apparent activation energies for the flow processes were calculated at a number of fixed water contents, and were found to vary between 26.3 and 110 kcal./mole.

Text

2012-01-12

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http://hdl.handle.net/2429/40016

Chemistry

University of British Columbia

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