Polyimide/graphene composite foam sheets with ultrahigh thermostability for electromagnetic interference shielding

Abstract

Herein Kapton-type aromatic polyimide (PI) composite foams with reduced graphene oxide (rGO) content ranging from 1 to 16 wt% have been fabricated via a three-step method: in situ polymerization, nonsolvent induced phase separation and thermal imidization, and used for electromagnetic interference shielding. The resultant PI/16 wt% rGO foam with low density of 0.28 g cm⁻³ and thickness of 0.8 mm exhibited an effective EMI shielding effectiveness of 17–21 dB in X band (8–12 GHz). Additionally, the thermostability of the foams was also significantly enhanced, for the 5% weight loss temperature it was improved from 508 °C for the pure PI foam to 520 °C for the PI/1 wt% rGO foam, and consequently, to 581 °C for the PI/16 wt% rGO foam. Even with the high rGO content (16 wt%), the composite foam was fairly flexible. Tensile testing revealed that the PI/16 wt% rGO foam possessed a tensile strength of 11.4 MPa and an elongation at break of 9.6%, respectively.