No abstract

Driven by rapidly growing demands in fields such as mobile electronics, aerospace and military, the need for functional materials with lightweight, good environmental stability and efficient electromagnetic interference (EMI) shielding properties has rose sharply. In this paper, quaternary nanocomposite foams comprising of poly(vinylidene fluoride) (PVDF), carbon nanotubes (CNTs), graphene nanoplatelets (GNPs) and Ni were developed by a melt blending and supercritical CO2 foaming technology. Compared with pure PVDF, the crystallization temperature of PVDF/2CNTs/2GNPs/12Ni nanocomposite increased remarkably from 139.0 to 144.9°C. Rising the nanofiller loading from 0 to 16 wt% led to the enhancements of around four orders of magnitude in the storage modulus of PVDF nanocomposites as well as about three orders of magnitude in their complex viscosity. For a typical PVDF/2CNTs/2GNPs/12Ni nanocomposite, its EMI shielding effectiveness reached 32.2 dB, brought by dielectric loss and magnetic loss. The electrical conductivity and EMI shielding effectiveness of PVDF nanocomposite foam achieved the optimum values of 0.84 S/m and 19.4 dB, respectively, which originated from the introduction of pore structure and the gradual generation of nanofiller‐nanofiller conductive networks. This study took a promising way toward the fabrication of materials with adjustable EMI shielding property in the fields of electronics and aerospace industries.

Nowadays, one of the design direction of bio‐derived and biodegradable polymer foams with multi‐functionalization is how to attain superior electromagnetic interference (EMI) shielding property, which has become a hot topic. Herein, bio‐based poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) foams filled with carbon nanotubes (CNTs) and/or graphene nanoplatelets (GNPs) were fabricated by supercritical carbon dioxide. As observed by optical microscope and scanning electron microscope, the CNTs and GNPs in PHBV matrix might gradually construct three kinds of network structures (CNTs‐CNTs, GNPs‐GNPs and GNPs‐CNTs network structures), which would improve the melt viscoelasticity, crystallization, electrical, dielectric and EMI shielding properties of PHBV. The complex viscosity and storage modulus of PHBV nanocomposites with the ratio of CNTs/GNPs as 1:1 rose nearly three orders of magnitudes than those of pure PHBV, in addition, its crystallization temperature and crystallinity increased remarkably to 122°C and 62%, individually. When the CNTs/GNPs ratio was 1:1 at a low total content of 3 wt%, PHBV nanocomposite and its foam implemented the high dielectric properties. Furthermore, the EMI specific shielding effectiveness of obtained PHBV was blend with 1.5 wt% CNTs and 1.5 wt% GNPs nanocomposite foam was the highest, reaching 19.3 dB cm3/g. This work paved a feasible way to the production of eco‐friendly PHBV nanocomposite foams for the application of electronics and aerospace industries.Highlights PHBV/CNTs/GNPs foams were prepared using a scCO2‐assisted foaming method. Dispersion of carbon fillers in PHBV was the best as CNTs/GNPs ratio was 1:1. G' of PHBV/C1.5/G1.5 specimens were increased by three orders of magnitude. EMI specific shielding effectiveness of PHBV/C1.5/G1.5 nanocomposite foam could reach 19.3 dB cm3/g.

No abstract

No abstract

No abstract