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Here, Ni@graphene nanoplatelet (GNP) nanohybrids are obtained via an interfacial reaction growth method and a series of poly(methyl methacrylate) (PMMA)/Ni@GNP composites are prepared by a solution mixing‐ultrasonic dispersion‐hot pressing technology. The influence of Ni@GNP on the electromagnetic interference (EMI) shielding, dielectric, and thermal management behaviors of the composites is intensively investigated. The microcapacitors formed using Ni@GNP as plates and PMMA as matrix significantly improve the dielectric properties of the composites. Enhancement on thermal conduction and EMI properties of PMMA composites with increasing Ni@GNP content can be ascribed to the unique structure of Ni@GNP and it is the filler interconnection network that renders the composite's desirable thermally conductive and thermomechanical properties. A facile way of fabricating polymeric composites with satisfactory thermal conductivity and high‐performance electromagnetic shielding is provided here. The obtained polymer composites display highly promising applications in the thermal management and EMI shielding of electronic devices. [ABSTRACT FROM AUTHOR]

In this study, a series of polyethylene thin films were prepared by thermally induced phase separation (TIPS) method with di(2-ethylhexyl)phthalate as the diluent. Morphological observations showed that the microstructures at different locations were fairly distinct and could generally be divided into three layers. When the polymer concentration was lower than the monotectic point (Φm), both pore size and porosity in TIPS films were heavily determined by growth time and growth rate of the diluent droplets. At relatively higher polymer concentration, cooling rate heavily affected the pore size in the films primarily through its influence on polymers' crystallization process. The relationship between the film microstructure and cooling rate was quantitatively investigated (especially the effect of quenching conditions on the evolution of film morphology) with the aid of an enthalpy transformation method, which established the three-dimensional temperature profiles and supplied an insight into the competition between phase separation kinetics and polymer crystallization. In addition, our findings showed that the pore size, porosity and thermal stability of films all increased with an increasing quenching temperature, which was significantly different from the trends of variation in water vapor transmission rate as well as the E max ′ and E max ″ values of dynamic mechanical analysis as the quenching temperature increased. The present work presents a facile way of in situ tailoring hierarchical microstructures in TIPS films of crystalline polymers, which will be very useful to the design of polymer porous films with specific properties. [ABSTRACT FROM AUTHOR]

Polystyrene-based wood plastic composites (WPCs) containing ammonium polyphosphate (APP) and iron (Fe) powder were prepared in this work by solution blending with the aid of an alternating magnetic field. The mechanical, electrical, thermal and fire performances of the WPCs were analyzed through mechanical testing, thermogravimetry and CONE calorimeter. The addition of Fe powder decreased the tensile strength and increased the impact strength. The APP promoted the formation of sufficient char on the material's surface and enhanced the flame retardant properties. Furthermore, an alternating magnetic field was used to align the Fe powders. After the magnetic treatment, the electrical conductivity and thermal properties were found to increase considerably compared with those without treatment. The Agari model presented the most reasonable prediction of thermal conductivity as a function of Fe content among three classical thermal conduction models. According to the morphological observations, the iron particles in the composites tended to rearrange along the direction of the magnetic field after treatment, resulting in the enhancement of both thermal and electrical conductivities. The prepared WPCs in this study exhibited good flame retardant properties together with the acceptable mechanical properties of the composites. [ABSTRACT FROM AUTHOR]