الفهرس 
Chapter 1: IntroductionOnly 14 pages are availabe for public view
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Abstract
Because of its good properties such as high temperature resistance and chemical resistance, PTFE is used in a wide range for industrial applications like textiles and other types of applications, but the big problem of PTFE is the high negative surface static charge when rubbing with other insulators. This energy can be considered as a reason for introducing spark.
In the present work, friction coefficient and electrostatic charge of PTFE composites were studied to develop new engineering materials with low friction coefficient and neutral or low electrostatic charge. Square test specimens ofPTFE composites (PTFE + Wool, PTFE + Acrylic, PTFE + PA, PTFE + Polyester and PTFE + Cotton) of different densities, were tested by sliding against {ceramic, car padding material (synthetic leather), home upholstery material (satin) and rubber}. A test rig was designed and manufactured to perform friction measurements under applied loads 5, 10, 15, 20 and 25 N. Ultra surface Dc voltmeter was used to measure the electrostatic charge.
Experiments show that the friction coefficients of PTFE composite containing wool and sliding against ceramic decreased remarkably to 0.2 with increase of wool content in composite to 30 vol. %. This behaviour recommended these composites for low friction coefficient applications. Besides, it was found that increase of polyester content in PTFE composite decreased slightly the friction coefficient to 0.22 for composites sliding against synthetic leather under low loads.
A significant decrease 111 the negative charge to -30 V for composite containing 50 vol. % polyamide contents sliding against ceramic was observed. Increase of acrylic contents in PTFE composite sliding against ceramic change the negative charge to +2 V for composites containing 50 vol. % acrylic contents.
PTFE composites containing polyamide sliding against rubber shows remarkable decrease of the electronegative charge of PTFE surface from -1350 V for composites free of polyamide to -3 V for composites of 30 vol. % polyamide content at 5 N applied load.