Multifunctional, Polyurethane-Based Foam Composites Reinforced by a Fabric Structure: Preparation, Mechanical, Acoustic, and EMI Shielding Properties

This study proposes multifunctional, fabric-reinforced composites (MFRCs) based on a bionic design, which are prepared by two-step foaming and a combination of different fabric constructs. MFRCs are evaluated in terms of sound absorption, compression resistance, electromagnetic interference shielding effectiveness (EMI SE), and drop impact, thereby examining the effects of fabric structures. The test results indicate that the enhanced composites have superiority functions when combined with carbon fabric in the upper layer and spacer fabric in the lower layer. They have maximum compression resistance, which is 116.9 kPa at a strain of 60%, and their compression strength is increased by 135.9% compared with the control specimen. As a result of the fabric structure on the cell morphology, the maximum resonance peak shifts toward high frequency when using spacer fabric as the intermediate layer. The average sound absorption coefficient is above 0.7 at 1000-4000 Hz. The reinforced composites possessed EMI SE of 50 dB at 2 GHz; an attenuation rate of 99.999% was obtained, suggesting a good practical application value. Furthermore, the cushioning effect of the MFRCs improved significantly, and the maximum dynamic contact force during the impact process was reduced by 57.28% compared with composites without any fabric structure. The resulting MFRCs are expected to be used as sound absorbent security walls, machinery equipment, and packaging for commercial EMI shielding applications in the future.