Textile creep measurements

Researchers have examined the creep and creep recovery of textile fibers extensively (13-21). For example, Hunt and Darlington (16, 17) studied the effects of temperature, humidity, and previous thermal history on the creep properties of Nylon 6,6. They were able to explain the shift in creep curves with changes in temperature and humidity. Lead-erman (19) studied the time dependence of creep at different temperatures and humidities. Shifts in creep curves due to changes in temperature and humidity were explained with simple equations and convenient shift factors. Morton and Hearle (21) also examined the dependence of fiber creep on temperature and humidity. Meredith (20) studied many mechanical properties, including creep of several generic fiber types. Phenomenological theory of linear viscoelasticity of semicrystalline polymers has been tested with creep measurements performed on textile fibers (18). From these works one can readily appreciate that creep behavior is affected by many factors on both practical and theoretical levels. 

Adsorption of transition metal species during processing, cellulose, 388 Advisory panels for standards for archival materials, potential benefits, 311 Age of cellulosic textiles determination from single-fiber creep measurements, 19-38 effect on crystallinity, 417 effect on rate of degradation, 416-17 Aged paper... 

The electrical conductivity of hydrophilic polyamides " and the photoconductivity of nylon-6,6" are reported. The time dependence of two transient photocurrents suggest the possible formation of a space charge in the polymer. Time-dependent effects in the form of creep measurements have also been used to examine the influence of moisture on the behaviour of nylon-6,6. Other low molecular weight molecules, whose effects on the properties of this polymer have been reported are surfactant and both acid and disperse dyes. Also with a textile connotation was a paper with more general application describing the determination of amino-acid N groups in nylon-6 and -6,6. ... 

The mechanical properties of textile fibers, yarns, and fabrics may be more fully determined by subjecting the substrate to small forces in directions other than along the fiber axis. Tear, bending, and shear strengths, as well as recovery from bending and abrasion resistance, etc., also influence the wear properties of textiles. Finally, time-dependent extension and recovery, termed creep, or creep recovery, respectively, is of importance in determining the performance of fibers in industrial applications. A discussion on the measurement of these parameters, however, is beyond the scope of this article. 

Figure 13.12 Belchatov-creeping assessment by multi-functional geotextUe (MFG) sensors, (a) Crack opening (detail) and (b) crack measurement with scale for the calibration of the readings from the optical sensors embedded in the textile.

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