ELECTRICAL PROPERTIES OF THE CONDUCTIVE KNITTED FABRIC REINFORCED THERMOPLASTIC COMPOSITES

Abstract

This paper reports a study to develop conductive thermoplastic composite materials for attenuation of the electrostatic discharge and immunity of the electromagnetic shielding effectiveness applications. In general, most of the plastics and composites are subjected to conductivity and electrostatic. To overcome these bottleneck, recently stainless steel/polyester/glass/ polypropylene (SS/PET/G/PP) knitted fabrics made from 5G flat knitting machine and their composites were developed successfully. Primary objects of this research are to develop a new material, which could be used in automobile, aerospace, electronic and electrical fields, for avoiding the electromagnetic and electrostatic discharge interference. Stainless steel wires are incorporated as conductive fillers to facilitate the electrostatic discharge (ESD) and electromagnetic shielding properties of the knitted fabric. To facilitate the knitting and reduce the material cost the uncommingled yams comprising stainless steel/polyester/glass/polypropylene yams are produced using a hollow spindle spinning method. The attenuation of the ESD for the various knitted fabric reinforced composites was obtained using an ESD immunity tester in the voltage range of 8kV and 12 kV. Typical waveforms of the output electrostatic discharge voltage on the oscilloscope have also been reported. The electromagnetic shielding effectiveness (EMSE) of various knitted composites was obtained using a coaxial transmission line holder in the frequency range of 300 kHz to 3 GHz. The variations of EMSE and ESD of knitted composites with the fabric structure, stitch density, number of plies, and the amount of stainless steel are described. Suitability of the knitted composites developed in this study for electromagnetic shielding applications is also discussed.