分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-08
Chen, YJ [Chen, Yuejuan][ 1 ]
Li, Y [Li, Yang][ 1 ]
Xu, DH [Xu, Donghua][ 2 ]
Zhai, WT [Zhai, Wentao][ 1 ]
摘要： Stretchable and flexible conductive polymers have aroused great interest recently because of their applications in the fields of novel electronics, such as smart textiles, artificial electronic skin, flexible electronic displays, etc. In this work, stretchable and flexible conductive thermoplastic polyurethane (TPU)/graphene composite foams have been developed by water vapour induced phase separation. The as-prepared TPU/graphene composite foams exhibited a lower modulus, larger elongation at break, and lower hysteresis during a cycle tensile test than a TPU/graphene composite did. It is expected that the improved elasticity of the TPU/graphene composite foams was caused by the deformation of cells, which partially offset the deformation of the TPU matrix. In addition, the cell walls divided the whole composites into many small parts, which could further restrain plastic deformation of hard segment domains under deformation.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Li, Y [Li, Yang][ 1 ]
Shen, B [Shen, Bin][ 1 ]
Pei, XL [Pei, Xueliang][ 2 ]
Zhang, YG [Zhang, Yonggang][ 2 ]
Yi, D [Yi, Da][ 3 ]
Zhai, WT [Zhai, Wentao][ 1 ]
Zhang, LH [Zhang, Lihua][ 1 ]
Wei, XC [Wei, Xingchang][ 3 ]
Zheng, WG [Zheng, Wenge][ 1 ]
摘要： Ultrathin carbon foams with the thickness about 24 mm were fabricated by the pyrolysis of polyimide/ graphene composite foams. The addition of graphene was verified to stabilize the porous structure of the foams and accelerate their graphitization process simultaneously. Consequently, the well-defined carbon foams exhibited much higher electromagnetic interference (EMI) shielding effectiveness (SE) up to 24 dB over the frequency range of 8e12 GHz, in comparison with the non-foamed counterparts. The possible mechanism behind the phenomenon was attributed to their enhanced microwave absorption via the internal multiple scattering and reflections. Moreover, the SE could be further improved to 43 and 51 dB by increasing the sample thickness gradually to 51 and 73 mm, respectively. The carbon foams with high thermal stability are very promising in the fabrication of ultrathin EMI shields for thermally harsh applications.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Shen, B [Shen, Bin][ 1 ]
Li, Y [Li, Yang][ 1 ]
Zhai, WT [Zhai, Wentao][ 1 ]
Zheng, WG [Zheng, Wenge][ 1 ]
摘要： The fabrication of low-density and compressible polymer/graphene composite (PGC) foams for adjustable electromagnetic interference (EMI) shielding remains a daunting challenge. Herein, ultralightweight and compressible PGC foams have been developed by simple solution dip-coating of graphene on commercial polyurethane (PU) sponges with highly porous network structure. The resultant PU/graphene (PUG) foams had a density as low as ∼0.027−0.030 g/cm3 and possessed good comprehensive EMI shielding performance together with an absorption-dominant mechanism, possibly due to both conductive dissipation and multiple reflections and scattering of EM waves by the inside 3D conductive graphene network. Moreover, by taking advantage of their remarkable compressibility, the shielding performance of the PUG foams could be simply adjusted through a simple mechanical compression, showing promise for adjustable EMI shielding. We believe that the strategy for fabricating PGC foams through a simple dip-coating method could potentially promote the large-scale production of lightweight foam materials for EMI shielding.
提交时间： 2017-05-02
Shen, B [Shen, Bin][ 1 ]
Li, Y [Li, Yang][ 1 ]
Yi, D [Yi, Da][ 2 ]
Zhai, WT [Zhai, Wentao][ 1 ]
Wei, XC [Wei, Xingchang][ 2 ]
Zheng, WG [Zheng, Wenge][ 1 ]
摘要： As reported, the foaming of layered graphene films into porous graphene foams could improve their performance for absorbents, catalysis and supercapacitors. Herein, to emphasize the impact of porous structure on electromagnetic interference [EMI] shieldin
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