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Your search keyword '"Wu, Hong"' showing total 31 results
31 results on '"Wu, Hong"'

30. Endowing the high efficiency thermally conductive and electrically insulating composites with excellent antistatic property through selectively multilayered distribution of diverse functional fillers.

Author

Zhang, Xiaomeng, Zhang, Jiajia, Li, Chunhai, Wang, Jianfeng, Xia, Lichao, Xu, Fang, Zhang, Xianlong, Wu, Hong, and Guo, Shaoyun

Subjects
*THERMAL conductivity, *PACKAGING materials, *ELECTRONIC equipment, *ANISOTROPY, *ELECTRICAL resistivity
Abstract

To fabricate thermally conductive while electrically insulating composites with excellent antistatic property is a huge challenge in the region of packaging materials of electronic devices due to the contradiction between the electrical insulation and the antistatic property. In the present work, the peculiar multilayer structures with alternating high efficiency thermally, electrically conductive layers and thermally conductive, electrically insulating layers were constructed successfully through a simple, one-step melt extrusion method. Such thermally conductive and electrically insulating composites possessed significant anisotropic electrical resistivity; for example, the in-plane electrical resistivities (parallel to the layer direction) were below 117 Ω × cm, while the through-plane electrical resistivities were over 5 × 10 13 Ω × cm. Meanwhile, with increasing the layer number, thermal conductivity of the composite with the same filler loading was improved monotonously, and reached as high as 1.45 W/(m × K) in the composite with 32 layers. In addition, tensile strength and elongation at break of the composites were also enhanced due to the different deformation mechanisms of separate layers. Furthermore, to give a deep insight into the enhancement mechanism of thermally conductive property, finite element analysis was applied and the results indicated that high efficiency thermally, electrically conductive layers possessed magnified effects on the heat dissipation. Therefore, the multilayer structure with alternating high efficiency thermally, electrically conductive layers and thermally conductive, electrically insulating layers can endow the composite with excellent comprehensive properties effectively, and it also sheds light on the design and fabrication of high performance materials for the applications of thermal management or other energy harvesting fields. [ABSTRACT FROM AUTHOR]

Published
2017
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31. Polycarbonate toughening with reduced graphene oxide: Toward high toughness, strength and notch resistance.

Author

Wang, Jianfeng, Li, Chunhai, Zhang, Xiaomeng, Xia, Lichao, Zhang, Xianlong, Wu, Hong, and Guo, Shaoyun

Subjects
*POLYCARBONATES, *GRAPHENE oxide, *STRENGTH of materials, *TENSILE strength, *IMPACT (Mechanics)
Abstract

The toughening effect of graphene sheets on polycarbonate (PC) was investigated to fabricate PC composites with excellent balanced toughness, notch resistance as well as strength. The reduced graphene oxide (RGO) was incorporated into PC matrix through melt compounding. A maximum toughening effect was observed in PC/RGO (PCG) composites with 0.03 wt% or 0.07 wt% RGO. Particularly, the tensile fracture toughness of PCG composites with 0.03 wt% RGO was enhanced by 89%. The notched impact strength and K IC of PCG composite with 0.07 wt% RGO was increased by 46% and 58%, respectively. The point of 0.1 wt% was found to be the ductile-brittle transition point in PCG composites. Meanwhile, the yield strength of these novel materials was increased by around 12% as well at loading of 0.07 wt%. Microcrack, resulting from interfacial debonding between PC and RGO as well as breakage and pulling out of graphene layer, was proposed to be the main toughening mechanism contributing to the great enhanced fracture toughness and notch resistance. Apart from the microcrack, crack pinning, crack deflection and crack arresting were also found and proposed to be toughening mechanism in notch-fractured process. This work not only provides us a novel strategy to fabricate advanced PC nanocomposites but also gives us a deep understanding on the toughening role of graphene on polymers. [ABSTRACT FROM AUTHOR]

Published
2017
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