Facile preparation of lightweight high-strength biodegradable polymer/multi-walled carbon nanotubes nanocomposite foams for electromagnetic interference shielding

Lightweight conductive polymer composites (CPCs) have been considered as the most promising alternatives to metal-based shields for electromagnetic interference (EMI) shielding application but still face non-degradation issues. We report a facile, inexpensive and green method to implement lightweight biodegradable poly (L-lactic acid) (PLLA)-multiwalled carbon nanotubes (MWCNTs) nanocomposite foams using a combinatorial technology of pressure-induced flow (PIF) processing and supercritical carbon dioxide (Sc-CO2) foaming. Such low-density (similar to 0.3 g/cm(3)), low thickness (similar to 2.5 mm), high compressive strength (similar to 54 MPa g(-1) cm(3))) and highly conductive (similar to 3.4 S m(-1)) PLLA-MWCNT nanocomposite foams were first reported as an EMI shielding material: it presents high performance EMI shielding with a remarkable effectiveness and a corresponding average specific EMI SE of similar to 23 dB and similar to 77 dB g(-1) cm(3), respectively, with less reflection in the measured X-band frequency region. Considering the simple, low-cost and eco-friendly fabrication process, the lightweight, high-strength and highly conductive biodegradable polymer composite foams are expected to be used as high-performance EMI shielding materials in areas such as electronics, automobiles and packaging. (C) 2016 Elsevier Ltd. All rights reserved.