HE Guangsen ¹ , ZHAO Tao ¹ , ZHU Pengli ¹ , SUN Rong ¹ , YU Shuhui ¹ , DU Ruxu ^1,2

(1.Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen Guangdong 518055; 2.The Chinese University of Hong Kong, Hong Kong 999077)

Abstract: The Ni particles were synthesized by aqueous chemical reduction and filled in PVDF matrix and formed Ni/PVDF composites via a grinding and the hot-molding technique. Dependence of dielectric properties of the composites between 10⁷~ 10⁹Hz on Ni volume fraction are studied. The thermal properties of the composites on Ni contents from 20℃ to 200℃ during the cooling cycle are also studied. The results show that within a general frequency range from 10⁷~ 10⁹ Hz, the dielectric permittivity and loss tangent increase with the filler content. The percolation threshold of the composites is 0.275 at 10⁷Hz. The dielectric constant and loss tangent of the composites decrease with the increase of frequency when the content of Ni particles is below 23.1vol%. When the content is 27.1vol%, the loss tangent has a minimum value at about 3.5×10 ⁸ Hz and when the frequency is above 3.5×10 ⁸Hz, the dielectric constant decreases quickly. With the increase of Ni contents, the peak crystallization temperature of the composites increases, while the crystallization enthalpy and crystallinity of the composites go down.

Key words: nickel; PVDF; composites; thermal properties; high frequency