中文摘要：

通过熔融共混然后压片的方法将碳黑（CB）颗粒分散在对太赫兹光透明的高密度聚乙烯（HDPE）基体中,采用太赫兹时域光谱装置测量了该体系的介电信息,首次尝试采用反向有效介质理论,在CB浓度固定、只改变去极化因子的情况下,提取了CB颗粒在该波段的介电常数实部和虚部、折射率和吸收系数等信息.研究发现,从不同浓度的复合体系中提取的数据吻合较好,结合直流电导率测量结果发现去极化因子与体系内部颗粒的浓度和存在状态紧密相关,在逾渗阈值处去极化因子显著降低.采用偶极子弛豫模型对提取的结果进行了理论分析,得到了CB颗粒的弛豫时间、弛豫强度和电导率等信息。

英文摘要：

Carbon black （CB） was dispersed into high density polyethylene （HDPE）,which was transparent to terahertz wave,by melt-mixing and compressing method.The dielectric properties of the composites in terahertz region were then investigated.Reversed effective medium approach （REMA） was firstly applied to the analysis of the composites.The real part and imaginary part of dielectric constants,refractive index and absorption coefficient of the pure CB particles were extracted with REMA from that of the composites with fixed concentration and an alterable parameter of depolarization factor.The results indicate that the calculated dielectric constants,absorption coefficient and refractive index of CB from different concentrations coincide well with each other.Combined with the direct current conductivity test,the depolarization factor was found to be correlated to the CB concentration and its distributing state in the composites.It has an apparent decrease at the percolation threshold of CB/HDPE composites.The extracted results were then analyzed with the dipole relaxation model.The relaxation time,relaxation strength and dc conductivity of the pure CB particles were obtained.