Some Fundamental Questions Concerning the Static Electrification of Textile Yarns: Part II

In order to study the generation of charge on fibrous materials, an apparatus was constructed in which a fiber is held fixed while a second is rubbed across it under controlled mechanical and ambient conditions. It was found that the reproducibility was usually within ± 5% when the same two fibers were rubbed repeatedly; that the charge generated was dependent on the manner in which the materials were rubbed; and that the magnitude of the charge generated was directly proportional to the length of material rubbed and to the normal force between the fibers (although in some cases a limiting maximum value was reached), but was independent of the apparent area of contact between the fibers and of the tension on the fibers. The effects produced by changes in velocity are more complicated to describe. Charge transfer was found to be independent of velocity when insulators (except Teflon) were rubbed together. For metals on insulators other than Teflon, the charge generated was found to increase linearly with velocity until a limiting value was reached, and then to remain constant. When Teflon and metals were rubbed together, the charge increased linearly with velocity without reaching a maximum. When Teflon was rubbed with insulators, the charge increased linearly with velocity in some cases but remained constant in others. A study of the dependence of the sign and amount of charge transferred on the nature of the materials rubbed was undertaken, and a triboelectric series was established. For metals on insulators, the amount of charge generated was found to be related to the work function of the metal and the position of the insulator in the triboelectric series. For insulators rubbed on insulators, the amount of charge transferred appeared to be independent of the positions of the insulators in the series.

Section: Nature Of the Contact Between Fibersmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Static Electrification of Filaments

Hersh

Montgomery

1955

“…In recent years several investigators have studied the static electrification of textile materials and polymer films, using a variety of methods ranging from different ways of passing yarns or fabrics over insulators or metals [ 2,20,21,23,27,30,47,50,56 to the generation and measurement of charge on bundles of fibers and slivers [39,47 ] . Studies have also been conducted on solids in the form of dusts or powders and measurements obtained of the charges formed on them when poured or blown into a cloud ( 10,11,13,14,17,42,60,62,63,67,78 ] .…”

Section: Introductionmentioning

confidence: 99%

Relation of Charge to Frictional Work in the Static Electrification of Filaments

Levy

Wakelin

Kauzmann

et al. 1958

A study of the generation of electrical charge on fibrous materials was carried out using the apparatus of Hersh and Montgomery, in which a fiber is held fixed in an insulated lower yoke while a second fiber in a grounded upper yoke is rubbed across it under controlled ambient and mechanical conditions. The original apparatus was modified to permit measurement of the frictional work of rubbing as well as the charge.Precautions were taken to discharge both fibers with a radioactive source after each measurement.It was found that, at any one velocity, several thousand rubs were required before steady values of charge transferred and frictional work of rubbing were obtained.It was also found that the velocity of rubbing affected strongly both the charge transferred and the frictional work of rubbing, the former being found to decrease and the latter to increase with increasing velocity. This has been explained in terms of local heating, plastic junctions, and material transfer which occur during rubbing. An empirical relationship relating the velocity of rub, the frictional work of rubbing, and the charge transferred was found to hold in the great majority of the cases examined.From the experimental data obtained it was possible to calculate the mechanical energy expended in any one rub and to estimate the resulting electrical energy. Thus for any pair of fibers under a given set of conditions it was possible to calculate the efficiency of the process of converting mechanical energy to triboelectrical energy. At 30° C. and 33% RH, measured efficiencies were very low (0.00-0.42%); at a very low humidity, efficiencies as high as 2.0% were found.The presence of a lubricant on the fiber surfaces during rubbing was found in most cases to cause a decrease in both the charge and frictional work of rubbing.

“…The two methods are shown to agree substantially. Methods IrrsertioK (2) in (1 ) and taking I = 2.5~ rrn., one obtain Now consider a yarn consisting of n such filaments. Assuming that each filament is uniformlv covered with finish, the resistance I~ of the bundle of n filuments (n parattet resistances) is Equation 6 is identical with (3) ; thus the resistance of a finished yarn is the same as that of a mono-503 tilnment of equal total denier, covered with the same total amount of finish.…”

Section: Introductionmentioning

confidence: 99%

“…'I'he tension in the yarn can be measured after the yarn has passed through the Faraday caKe, usiiig the familiar Statharii gauge and 'I'he apparatus is similar to the one described by <tonsa!vcs [2]; the main difference is that our apparatus measures charge distribution rather than the average charge on a IonK sample. The apparatus simulates plant conditions better than Hersh's (1 ) apparatus.…”

mentioning

confidence: 99%

Electrostatic Properties of Finished Cellulose Acetate Yarn1

Sprokel¹

1957

Instruments are described to. measure the resistance of yarn samples and the charge build-up on the yarn as it is rubbed against a metal post. The resistance of acetate yarn can be calculated from the specific conductivity of the finish solution; the resistance of rayon yarn is much lower and is more affected by the yarn itself. The resistance of the sample determines how fast charge can leak off. If the resistance is smaller than 10 12 or 10 13 ohms in., charge cannot be detected at some distance from the point of generation, The generation of the charge is not well understood. A quantitative relation does exist between the charge on the yarn and the angle of wrap and the yarn tension. It is very desirable that the antistatic agent help to spread the finish solution over the yarn surlace.