Microwave absorption and mechanical properties of glass fiber/polyamide 6 composites containing carbon black by microstructural design

Microwave absorbing composite laminates were prepared by a simple hot pressing process using glass fiber reinforced polyamide 6 (GF/PA6) doped with different content of carbon black (CB). The microwave absorption and mechanical properties of the composites were investigated. 8 wt% CB/GF/PA6 composite had a minimum reflection loss (RL) of -40.05 dB and the bandwidth of RL <= -10 dB is 4.6 GHz. The flexural strength was 207.2 +/- 10.7 MPa, the shearing strength was 26.0 +/- 1.1 MPa, and the impact strength was 71.2 +/- 5.7 kJ/m2. Moreover, the microstructure of the composites was tailored by disc granulation method to obtain reticular microstructure composed of different particle sizes to improve the microwave absorption and mechanical properties of the composites. It was found that the RL of 7 wt% granulated CB/GF/PA6 composite was -56.45 dB. The flexural strength was 214.9 +/- 4.4 MPa, the shearing strength was 21.7 +/- 0.5 MPa, and the impact strength was 88.0 +/- 8.5 kJ/m2. This method facilitated the integration of structure and function.