For the preparation of lightweight and high-performance electromagnetic interference shielding material, the poor dispersion of carbon nanotubes (CNTs) and weak interfacial strength degrade the mechanical properties of the polymer-based composite with extremely high filler contents. Herein cellulose nanofibers (CNFs) prepared by TEMPO-mediated oxidation exhibits a dispersive action for multiwalled carbon nanotube (MWCNTs) without chemical functionalization of the MWCNTs or the use of surfactant. Thus a robust and flexible CNF/MWCNT composite film can be fabricated by simple vacuum filtration and hot-pressing method. This composite film (thickness 0.15 mm) shows an electromagnetic interference shielding effectiveness (EMI SE) of 45.8 dB in the X-band. Thanks to the all-fiber structure and the association between CNFs and MWCNTs, it exhibits good flexibility and tensile strength up to 48 MPa, which is superior to other reported MWCNT-based films for electromagnetic shielding, giving it the potential to be used in flexible electronics and wearable devices.

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A PEG-b-CTBN diblock copolymer was synthesized via the esterification reaction of hydroxy terminated methoxypolyethylene glycols (PEG) in the presence of a carboxyl-terminated butadiene-co-acrylonitrile copolymer (CTBN) with 4-dimethylaminopyridine (DMAP) as the catalyst. Epoxy thermosets were modified via the formation of a nanostructure. The result of transmission electronic microscopy (TEM)shows spherical domains were homogeneously dispersed into the continuous epoxy matrix and the size is nano-scale. It was noted that the glass transition temperatures decreased with an increase in the content of PEG-b-CTBN, which was evidenced by Dynamic Mechanical Analysis (DMA) and a Differential Scanning Calorimeter (DSC). Through mechanical tests, we found the tensile strength and fracture toughness of epoxy resins were simultaneously enhanced by nanostructured PEG-b-CTBN.

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