Multi-functional CNT nanopaper polyurethane nanocomposite fabricated by ultrasonic infiltration and dip soaking processes

Carbon nanotube (CNT) nanopaper (NP) reinforced thermoplastic polyurethane (TPU) multi-functional thin nanocomposites were fabricated by novel ultrasonic infiltration method and dip soaking without using any organic solvent. Uniform resin infiltration with high loading CNT (26 wt %) was achieved in the nanocomposites. The resin infiltration time was reduced to 4 s in the ultrasonic method which greatly favored full scale production. Besides multi wall carbon nanotube (MWNT) NP, hybrid NP with 10% single wall carbon nanotube (SWNT) was used to improve the nanocomposite's mechanical and electromagnetic interference (EMI) shielding properties. The 10% SWNT NP TPU nanocomposite exhibited 2170% increase in tensile strength, and 7170% increase in Young's modulus compared to pure TPU, and reached a strain at break of 296%. Due to the high electrical conductivity and aspect ratio of SWNT, the thin hybrid NP nanocomposite (100 μm thick) demonstrated high and stable EMI shielding effectiveness (35 dB) after large deformation (100% strain extension). As coating application, the NP nanocomposites obtained 45 times improvement in sand erosion resistance, compared to glass fiber epoxy composite substrate. Micro injection molding was conducted using the NP TPU nanocomposite as raw material which indicated good process flexibility. The NP demonstrated to be a good platform to fabricate multi-functional TPU nanocomposites, with potential applications in wind energy, aerospace and automotive industries, etc.