Manufacture and effectiveness evaluations of high-modulus electromagnetic interference shielding/puncture resisting composites

The EMI shielding composites consisted of carbon fabric and nonwovens were developed based on needle punching and thermal bonding techniques, and their static and dynamic puncture resistances were also evaluated to resist against different puncture behaviors. The result shows that, needle-punched density and thermal bonding correlate with the EMI shielding effectiveness (SE) at particular medium and high frequency range, and respectively has interaction effect with number of layers. The mechanism of EMI shielding is reflection and absorption loss in medium-frequency, and only absorption loss in high-frequency. The static and dynamic puncture resistances improve linearly with number of layers, but both display an upward and then downward trend at increasing needle-punched density. After thermal bonding, the influence of thickness on static puncture resistance becomes significantly but on dynamic puncture resistance insignificantly. The resultant composites are expected to be used as wall interlayer and package interline in the future.