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Isolation structure has been proven to be an effective method for constructing electromagnetic shielding composites, achieving high electrical conductivity with shallow filler content and high‐efficiency electromagnetic shielding. However, there are still many challenges in further optimizing the design and improving absorption. This article designed a hybrid isolation structure using nylon magnetic microspheres and polystyrene (PS). First, we prepared PA magnetic microspheres (Ni@PA6M) with Ni nanoparticles uniformly dispersed by the reaction induced phase separation (RIPS) method, then mixed with MWCNT and PS at high speed and formed by hot pressing. Under the optimized ratio, the hybrid structure has more interfaces and a more complete conductive network. Simultaneously, the magnetic microspheres can promote the absorption of electromagnetic waves, thereby improving the electromagnetic shielding performance of the material. When the MWCNT content is 7 wt%, Ni@PA6M:PS = 7:3, the total shielding effectiveness (EMI SET) and reflection coefficient (R) of the composite reached 28.6 dB and 0.77, respectively, while the EMI SET and R of the composite constructed with pure nylon microspheres and PS are 26.1 dB and 0.74, respectively. Further, using supercritical CO2 foaming technology to foam the PS phase in the composite to form many cells can improve the impedance matching and absorption of electromagnetic waves. The results show that introducing the cell structure reduces the reflection coefficient (R) from 0.77 to 0.69, and the EMI SET drops to a certain extent. Introducing the hybrid isolation and porous structure we designed provides a new idea for creating electromagnetic shielding materials for isolation structures. [ABSTRACT FROM AUTHOR]

Green electromagnetic interference (EMI) shielding materials have been popularly accepted as the most promising EMI shielding material used in the electronic industrial community. Nevertheless, the design and optimization for both material and structure to achieve this function remain many challenges. Herein, Fe3O4@PA6 microspheres were fabricated by an unusual reaction‐induced phase separation method, where Fe3O4 nanoparticles were in situ introduced into the polymerization system. Interestingly, most Fe3O4 nanoparticles spontaneously immigrated into PA6 microsphere, forming Fe3O4@PA6 composite microspheres, and more interestingly, the saturation magnetization and particle size of the microspheres are highly associated. Therefore, the microspheres with specific particle size and magnetic property were easily obtained by simple sieving. These microspheres were then coated by MWCNT and hot‐compressed into EMI materials with segregated structures. A multilayered structure with positive conductivity gradients and negative magnetic gradients were created. Due to this structure, electromagnetic wave can enter the materials from the impedance matching channel without a large amount of reflection on the surface. The results show that with the increase in the number of composite layers, the EMI SE increases to 24.8 dB, and the R‐value is significantly reduced to 0.51. This work provides a new feasible idea for designing low‐reflection EMI composites. [ABSTRACT FROM AUTHOR]

ABSTRACT To improve dielectric performance of polystyrene (PS) without sacrificing its flexibility and processability, PS encapsulated graphene sheets (PSG) were synthesized by ultrasonically initiated in situ polymerization and was incorporated into PS matrix as fillers. The structure and properties of the obtained PSG were investigated by Fourier transform infrared, transmission electron microscopy, scanning electron microscope, and atom force microscopies. The results showed that the in situ formed PS layers attached on the surface of graphene and there were strong interfacial interactions between them. In virtue of this core-shell architecture and intrinsic properties of PSG, PS/PSG nanocomposites exhibited improved dielectric performance and a typical percolation transition with very low percolation threshold of 0.2 wt %. Compared with pure PS, significantly increased dielectric permittivity and a low loss tangent were observed for the composites. These composites might be potential flexible dielectric materials for use in high-frequency capacitors with low loss. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44628. [ABSTRACT FROM AUTHOR]

ABSTRACT Poly(ionic liquid)s have been demonstrated as high efficient CO2 absorbents. In the current study, a kind of poly(ionic liquid)s, Poly[2-(methacryloyloxy)-ethyl] trimethylammonium tetrafluoroborate (P[MATMA][BF4]) was used to functionalize graphene oxide (GO). The hybrid in which P[MATMA][BF4] was covalently bonded on GO platelets was prepared by a simple method, that is, traditional radical polymerization. The characterizations based on transmission electron microscopy, scanning electron microscope, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy demonstrated the graft of P[MATMA][BF4] on GO. N2 adsorption measurements indicated that P[MATMA][BF4] also greatly increased the specific surface area of GO. Due to the higher specific surface area and the CO2 affinity of P[MATMA][BF4], the GO-P[MATMA][BF4] hybrid exhibited a much higher CO2 adsorption capacity compared with GO, GO-NH2, and P[MATMA][BF4]. Their study showed that the combinations of poly(ionic liquid)s and GO could be promising CO2 absorbents. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44592. [ABSTRACT FROM AUTHOR]

ABSTRACT Three surface modifiers, namely, aminopolyether (D2000), phenyl isocyanate, and poly(ethylene glycol) (PEG800), which have different affinities to the hard and soft segments in polyurea, were used to synthesize functionalized graphite oxides (GO). The PEG800-modified (PEG800-GO) and phenyl isocyanate-modified (i-GO) GOs were highly exfoliated and dispersed in DMF, whereas the D2000-modified GO (D2000-GO) produced some precipitates. Polyurea/GO composites were prepared using a solution-blending method, in which functionalized GO platelet suspensions in dimethyl formamide were used. Results show that PEG800-GO and i-GO are uniformly dispersed throughout the polymer matrix on a nanoscale, whereas D2000-GO forms visible aggregates. The well-dispersed GO platelets improved the thermal stability and mechanical properties of polyurea. PEG800-GO, which has a strong affinity for the soft segments, shows a more significant reinforcing effect. At 2.0 wt % GO loading, the tensile strength of polyurea was enhanced by ∼75%. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39775. [ABSTRACT FROM AUTHOR]