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

• Published in: RSC advances 2015-01, Vol.5 (31), p.24342-24351
• Main Authors: Li, Yang, Pei, Xueliang, Shen, Bin, Zhai, Wentao, Zhang, Lihua, Zheng, Wenge
• Format: Article
• Language: English
• Subjects: Density; Electromagnetic interference shielding; Elongation; Foams; Graphene; Oxides; Polyimide resins; Thermal stability
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c4ra16421k

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. Flexible PI/rGO composite foam sheets were fabricated via nonsolvent induced phase separation and exhibited effective EMI SE at low sample thickness.