| Static electricity has been a major problem for textile manufacturing as well as consumers, especially after the introduction of manmade fibers. Extensive research has been done in this field; however, there are still questions not answered, and drawbacks. For example, the accuracy of the measurement is questionable due to the manual transfer of samples to the measuring unit, the devices and procedures are complicated and the results are not reproducible.;The goal of this research was to gain a better understanding on the mechanism of static generation and dissipation and to find the effects of different parameters on electrostatic behavior of polymeric surfaces. To realize this goal, precise material handling/cleaning and testing procedures were developed and three automated devices for electrostatic measurement were used. The devices were a linear tester, a rubbing tester, and a contact tester. The description of the devices and the analysis of signal obtained are given in Chapter 4, 5, and 6. The charge generation and dissipation behaviors of different polymers were investigated and compared. The effects of different parameters, such as the rubbing speed, contact force, environmental conditions, and antistatic finishes, are analyzed, and suggestions are given to textile industries based on the studies.;In this dissertation, literatures are reviewed in Chapter 2. The objectives are given in Chapter 3. Chapters 4, 5, 6, and 7 were modified from four manuscripts, which had been submitted to journals. The overall conclusions and suggestions for future work are given in Chapter 8.;Chapter 4 discusses the electrification produced by running a yarn against a guide and it was found that charge could be effectively controlled by reducing the relative rubbing speed between two surfaces. For several applications in textile industry, it is suggested that rotating rollers would be better than fixed guides for electrostatic control.;Chapter 5 addresses research on rubbing electrification between finish free polymeric plates and stainless steel plate. It is shown that charge accumulates in repeating rubbing and reaches the saturation after 2--3 cycles of rubbing PP and PTFE, while the charge reaches saturation after 40--50 cycles of rubbing nylon. This could be related to the difference of charge dissipation behavior of different polymers. The charge saturation is reached when the charge generation and dissipation are in balance. It is found that charge decays exponentially on nylon and the charge retained is about 60% or lower after 30 seconds, while, there is no decay on PP or PTFE during 30 seconds of observation.;Chapter 6 shows research on contact charging between polymeric plates. It is also shown that charge increases as the contact force increases. In addition, the tribo-electric series were found for nylon, stainless steel, PP, and PTFE by contact against each other.;Chapter 7 reports investigation in regards to contact charging and frictional charging on polymeric plates and yarns treated by antistatic finishes. It is found that ionic finish performs better than nonionic finish on both nylon and PP, and cationic finish works better than anionic finish due to difference in antistatic mechanism. From the observation of charge decay, it is found that there are two types of charge on nylon surface, which have different decay properties resulting from decay through air and spread on the surface.;In summary, systematic studies were conducted using newly developed automated devices, on finish free polymers and polymers with different antistatic finishes. From the experiments and analysis, the charge generation and dissipation on commonly used polymeric surfaces were better understood. Furthermore, suggestions were given to textile industry for reducing/eliminating static. |
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