High‐performance thermoplastic hybrid composite reinforced with bucky paper for electromagnetic interference shielding

Multiwalled carbon nanotubes (MWCNTs) have extraordinary electrical conductivity but limited applications due to the ease of agglomeration, especially in thermoplastic composite. With the aim of achieving high electromagnetic interference shielding performance by applying MWCNTs in thermoplastic matrix, MWCNTs were made into buckypaper (BP) and then hot pressed with PP/PLA/TiO₂ hybrid films, forming sandwich‐structured BP/PP‐PLA‐TiO₂ hybrid composite films. BP was examined in terms of morphology, cell structure, and electrical conductivity, while BP/PP‐PLA‐TiO₂ hybrid composite film was tested for electromagnetic shielding effectiveness (EMSE), thermal properties and UV‐cut efficacy. It was found that using vacuum filtration successfully produced BP with a smooth and sleek surface and an even porosity ranging between 20 and 45 nm. The electrical conductivity of BP was proportional to its thickness. About 90 μm‐thick BP had 75.62% lower surface resistivity and 36.63% higher electrical conductivity than 30 μm‐thick BP. Moreover, the EMSE of BP/PP‐PLA‐TiO₂ composite film increased as a result of the higher thickness of BP. When the thickness of BPs was 90 μm, the BP/PP‐PLA‐TiO₂ composite film had an average EMSE of 40 dB at 0–3 GHz and a peak of 70 dB, and 119% higher tensile strength and 11% higher elastic modulus than those of PP/PLA/TiO₂ composite film. BP/PP‐PLA‐TiO₂ composite film had UV‐cut efficacy that was close to 0%. The addition of BP was proven to improve the crystallization and thermal stability. POLYM. COMPOS., 40:3065–3074, 2019. © 2018 Society of Plastics Engineers