LAUSR

Abstract Vapor-grown carbon fiber (VGCF)-based polyurethane foam (VGCF@PUF) was fabricated by H2O–N, N-dimethyl formamide (DMF) solvent exchange for compaction-adjustable high-performance microwave shielding. VGCF@PUF specimens with different thicknesses were obtained by compression molding at 120 °C and 0–20 MPa. Tensile tests indicated that the hot compression enhanced both the mechanical strength and elongation of the VGCF@PUF. Moreover, with increasing compression, the electrical conductivity (σ) of the VGCF@PUF was improved by orders of magnitude. This indicated that the effective inter-connection of VGCFs achieved by hot compression is vital for enhancing the electrical conductivity of the VGCF@PUF. As for the microwave shielding, the results showed that increasing compression greatly improved the microwave shielding performance of the VGCF@PUF. For example, the VGCF@PUF specimen with approximately 25 wt% VGCF, which had thicknesses of 1.96 mm and 0.45 mm before and after hot-compression, respectively, revealed a change in shielding effectiveness (SE) from 10-15 dB to 35–50 dB. This is because the hot compression was considered to efficiently improve the electrical inter-connection of the nanoscale carbon nanofibers in the VGCF@PUF. This research demonstrated that the structure optimization of shielding materials is of great importance for improvement of electrical conductivity and microwave shielding performance.