Dielectric properties and conductivity of carbon nanofiber/semi-crystalline polymer composites
Dielectric properties and conductivity of carbon nanofiber/semi-crystalline polymer composites
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DOI：
10.1016/j.actamat.2008.01.034
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发表时间：
2008-06
期刊：
影响因子：
9.4
通讯作者：
G. Sui;S. Jana;W. Zhong;M. Fuqua;C. Ulven
中科院分区：
文献类型：
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作者：
G. Sui;S. Jana;W. Zhong;M. Fuqua;C. Ulven
半结晶聚合物纳米复合材料的性能直接和间接地受到纳米填料的影响，作为两相，即，结晶的和无定形的存在于聚合物中。纳米填料对两相的影响可能是竞争性的。研究了纳米碳纤维（CNF）/半结晶聚合物纳米复合材料的介电性能和导电性能。采用熔融共混法制备了CNF/PP纳米复合材料。通过差示扫描量热法、广角X射线衍射和扫描电子显微镜对所得的形貌和晶体结构进行了表征。PP纳米复合材料含有5 wt.% CNF在宽扫描频率下表现出令人惊讶的高介电常数，伴随着低介电损耗。其介电常数在较低频率下>600，在4000 Hz频率下保持>200。研究了纳米复合材料的电导率和热导率，发现随着CNF含量的增加，复合材料的电导率和热导率都有所提高。应用已有的模型对材料的物理性质进行了理论分析。研究结果表明，通过简单的工业化生产工艺，得到了一种综合性能良好的普通商用塑料，具有在先进电子产品中应用的潜力。
The properties of semi-crystalline polymer nanocomposites are affected by the nanofillers directly and indirectly, as two phases, i.e., crystalline and amorphous, exist in the polymer. The effects of nanofillers on the two phases could be competitive. The dielectric properties and conductivity of carbon nanofibers (CNF)/semi-crystalline polymer nanocomposites are studied in this paper. CNF/polypropylene (PP) nanocomposites are prepared in experiment by melt blending. The resulting morphology and crystalline structure are characterized by means of differential scanning calorimetry, wide angle X-ray diffraction and scanning electron microscopy. The PP nanocomposite containing 5wt.% CNF exhibits a surprisingly high dielectric constant under wide sweep frequencies attended by low dielectric loss. Its dielectric constant is >600 under lower frequency, and remains >200 at a frequency of 4000Hz. The electrical and thermal conductivities of the nanocomposites are studied, and enhancements are seen with increased CNF content. Theoretical analyses on the physical properties are carried out by applying the existing models. Research results indicate that a common commercial plastic with good comprehensive performance, which exhibited the potential for applications in advanced electronics, was obtained by a simple industry benign technique.