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.
The resistance of single textile fibers and assemblies of these fibers has been studied because of its relation to the effects of static electricity in fibrous materials. An apparatus has been con structed to measure resistances of fibers and assemblies from 108 to 10 16 ohms at specified tem peratures and relative humidities. Results of measurements at 30°C on some natural fibers (wool, cotton, hair, silk) and on some man-made fibers (rayon, acetate, nylon, casein) are given for relative humidities from 52% to 85%. Some other synthetic fibers (Orlon, Dacron, Dynel, polyethylene, Velon) have resistances too high to be measured conveniently with the present apparatus. All of the materials measured were found to be ohmic and largely free from polari zation effects at voltage gradients up to several hundred volts per centimeter, the limiting values used in the study. The resistivities of all materials tested decreased rapidly with increasing moisture content of the material, the resistivity varying inversely as the 7th to 13th power of the moisture content. Reasonable correlations were found to exist between the resistances of fiber assemblies and the constituents thereof.
In this paper we consider the wide-angle x-ray diffraction patterns of several nylon 66-polyethylene glycol (PEG) blend fibers before and after aqueous extraction. Antistatic additives such as PEG are frequently found in polyamide fibers. The patent literature indicates, however, that fiber blend systems of this type must be extracted in order to function effectively as antistatic fibers.'**The fibers examined in this study were prepared by an industrial laboratory by melt spinning mixtures of PEG and nylon 66 polymer chip. The samples ranged in composition from 0-20% PEG by weight in increments of 5%. The PEG had a molecular weight of ca. 20,000 (Union Carbide Corporation's polyethylene glycol compound 20M). After melt spinning, each blend was drawn to the same draw ratio of approximately 5X. Samples of each blend were extracted in an aqueous solution containing 10 ghiter of Oryus-AB detergent (Proctor and Gamble) for 3 hr at 7OoC and then dried in hot air at 7OoC for 2 hr. All samples containing PEG additive show a significant increase in electrical cond~ctivity.~The wide-angle pattern of the 100% unextracted nylon 66 fiber sample is shown in Figure 1. This structure has been completely analyzed by Bunn and Gardner.' The x-ray pattern of extracted samples of nylon 66 is practically unchanged except the major reflection peaks on the equator are somewhat sharper. The extraction process induces changes approximately equivalent to an annealing treatment of 200OC for 1 min.
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