Developing a Cost-Effective Composite Based on Electroless Nickel-Coated Cellulose Fibres for Electromagnetic Interference Shielding

A series of composites based on polypropylene with different loadings of nickel-coated cellulose fibres (NCCF) were fabricated with the aim to create a composite suitable for EMI shielding and/or electrostatic discharge application. Various properties such as EMI shielding effectiveness, surface resistivity, volume resistivity and flexural strength were characterised according to ASTM standard. Both surface and volume resistivity suggested that the electrical conductivity of NCCF was not high enough and the composite remains electrically non-conducting up to 40 wt% loading of NCCF. However, nickel particles were still able to shield electromagnetic radiation regardless of their connectivity and conductivity. This was reinforced by EMI shielding measurement which showed that EMI shielding effectiveness of 6.5 dB was obtained by composite containing 40 wt% NCCF. Mechanical property characterisation showed that the NCCF composites have higher flexural strength than pure polypropylene. This is a positive effect as NCCF is now acting as a conducting reinforcing material rather than simply a conducting filler. Furthermore, the composites maintained approximately similar flexural strength regardless of the loading of NCCF.