Room-Temperature Ferromagnetic Sr₃YCo₄O_10+δ and Carbon Black-Reinforced Polyvinylidenefluoride Composites toward High-Performance Electromagnetic Interference Shielding

Abstract

In this study, we fabricated composites of conducting carbon black (CB), room-temperature ferromagnetic Sr 3 YCo 4 O 10+δ (SYCO) and polyvinylidenefluoride (PVDF) by the solution mixing and coagulation method for the first time. During the nucleation process of PVDF, the presence of SYCO and CB individually facilitates the crystallization of polar β and semipolar γ phases along with the nonpolar α phase in PVDF. The dc electrical conductivity of PVDF raised from 1.54 × 10 –8 to 9.97 S/m with the addition of 30 wt % of CB, and it is nearly constant with respect to the SYCO content. The PVDF/CB/SYCO composites (PCS) possess high permittivity and its variation is in accordance with the content of polar phases in PVDF. Moreover, the complex permittivity and permeability spectra from 10 MHz to 1 GHz indicate that the dielectric loss dictates over magnetic loss in these composites. The electromagnetic interference shielding effectiveness (EMI SE) of PCS composites is higher than that of PVDF/CB and PVDF/SYCO composites in the 8.2–18 GHz region. Addition of SYCO in the PVDF/CB matrix enhances shielding by dominated absorption with minimal reflection. The analysis of the shielding mechanism suggests that in addition to conducting and magnetic losses due to CB and SYCO, respectively, the synergy among CB, SYCO, and PVDF promotes shielding by matching the input impedance to that of free space, enhancing multiple internal reflections from SYCO and subsequent absorption by CB, eddy current losses, dielectric damping losses, interfacial polarization losses, and so forth. These different mechanisms result in an enhanced EMI SE of 50.2 dB for the PCS-40 composite for a thickness of 2.5 mm.

Lightweight Cellulose Nanofibril/Reduced Graphene Oxide Aerogels with Unidirectional Pores for Efficient Electromagnetic Interference Shielding

“…And absorption loss comes from ohmic and heat loss in the shielding material. [ 48 ] SE M is neglected when SE T is over 15 dB. [ 49 ]…”

Dielectric and electromagnetic interference shielding properties of zeolite13Xand carbon black nanoparticles basedPVDFnanocomposites

“…However, with a further increase in the CBNPs loading (Figure 3(e, f)), the peak intensity at 2θ = 20.2° gradually decreases with a gradual increase in the intensity of other peaks. For PVDF/CBNPs nanocomposite (90/10) (Figure 3(g)), the relative intensity of the PVDF peak at 2θ = 20.2° shows a gradual decrease while the characteristic peaks at 2θ = 44.3° and 2θ = 64.2° displays a gradual increase indicating the effective reinforcement of CBNPs into the PVDF matrix 42 . The variations in the intensity of XRD peaks show that the addition of nanofillers has strongly influenced the crystallinity of the polymeric chains.…”

“…For PVDF/ CBNPs nanocomposite (90/10) (Figure 3(g)), the relative intensity of the PVDF peak at 2θ = 20.2 shows a gradual decrease while the characteristic peaks at 2θ = 44.3 and 2θ = 64.2 displays a gradual increase indicating the effective reinforcement of CBNPs into the PVDF matrix. 42 The variations in the intensity of XRD peaks show that the addition of nanofillers has strongly influenced the crystallinity of the polymeric chains. Therefore, the crystallite sizes were evaluated using the Scherer formula for all the nanocomposite films and results are depicted in Table 2.…”

Progress in polymers and polymer composites used as efficient materials for EMI shielding

“…Novel composites consisting of polyvinylidene fluoride, conductive carbon black and ferromagnetic Sr 3 YCo 4 O 10+ δ (SYCO), prepared by the solution blending and coagulation method, were deeply studied for the first time in the work. 273 It was revealed that during the nucleation process of PVDF, CB and SYCO facilitated the crystallization of semipolar γ and polar β phases, as well as the nonpolar α phase in PVDF matrix. The electrical dc conductivity of PVDF significantly increased from 1.54 × 10 −8 to 9.97 S m −1 with application of 30 wt% CB, and it was almost constant with respect to the content of SYCO.…”

“…Novel composites consisting of polyvinylidenefluoride, conductive carbon black and ferromagnetic Sr 3 YCo 4 O 10+δ (SYCO), prepared by the solution blending and coagulation method, were for the first time deeply studied in the work [273]. It was revealed that during respectively.…”