Multi-Response Optimisation for the Development of an Activated Carbon Web as Interlining for Higher Electrical Conductivity and EMI Shielding Using Grey Relational Analysis

Abstract

This paper presents a simple and novel method of producing an activated carbon (AC) non-woven web from acrylic waste derived from discarded bathmats converted into a nonwoven web by a carding and needle punching machine. After stabilisation at lower temperature, carbonisation of the stabilised web was performed in a muffle furnace. The carbonisation temperature, the holding time of the activated carbon web at the final temperature, the heating rate to reach the final carbonisation temperature and the number of steps adopted for developing the carbon web were optimised using the grey relational analysis (GRA) approach to get optimum responses of the surface area of the web, electrical conductivity and electromagnetic shielding. The results demonstrated a large improvement in electrical conductivity as surface resistivity decreased from 134.21 Ω.mm to 0.28 Ω.mm, and the corresponding electromagnetic shielding increased to 82.63 dB when the temperature of the carbonisation, the holding time and number of steps were increased. The surface area in the AC web was increased from 73 m2g-1 to 210 m2g-1 with an increase in the carbonisation temperature, the holding time and number of steps to reach the final temperature. The optimisation technique used in this work could be successfully used in cost and error reduction while producing an AC web. The optimised AC web was characterised by Brunauer, Emmett and Teller (BET), X-ray diffraction characterisation and elemental analysis (EDX) in order to determine changes in its structure, surface area, degree of crystallinity, inter-layer spacing and proportion of different elements. The AC web developed can be effectively employed as interlining in apparels because of its flexibility and eco-friendly electromagnetic shielding, as it works on the principle of the absorption, reflections and internal reflections of electromagnetic radiations.