Charge transport characteristics of ldpe/hdpe under different electric fields

Summary

The performances of charges under electric filed may provide much information related to the aggregation structure of polymers. The differences in the aggregation structure of polymers materials will result in diverse macroscopic electrical properties. Researching charge transport characteristics under high and low electric field within polyethylene is an appropriate way to understand its electrical properties. In this paper, the characteristics of charge transport under high and low electric field in low density polyethylene (LDPE) and high density polyethylene (HDPE) were investigated based on isothermal surface potential decay (ISPD) and isothermal relaxation current (IRC) method, respectively. And the aggregation structure features of LDPE and HDPE were considered to analyse the charge transport process under low and high electric field. It is shown that the obtained trap energy level range of LDPE and HDPE is 0.75~1.25 eV under high electric field based on ISPD. Additionally, LDPE possesses more shallow traps and a faster migrating process than HDPE. On the other hand, LDPE is easier to be polarized than HDPE under low electric field based on IRC in which LDPE possesses a higher polarization quantity and a shallower energy level. It is shown that the distribution of traps and energy level were similar under high and low electric field in LDPE and HDPE, indicating the ISPD method under high electric field and IRC method under low electric field can complement each other when they were adopted to characterize charge transport performances in LDPE and HDPE. It is implied that deep traps may play a more significant role in the charge migration process under high electric field. However, the polarization process presenting in the IRC measurements was mainly determined by shallow traps. It is concluded that the difference of charge transport properties between LDPE and HDPE was closely related to the change of the aggregation structure. Combining these two test results, more wide-range and comprehensive internal structure information can be obtained, and we can study the charge transport characteristics in the polymers through the combination of ISPD and IRC methods.

Additional informations

Authors

J. Li, F. ZHOU, X. ZHANG, Y. Yang

Keywords

Charge transport, isothermal surface potential decay, isothermal relaxation current, trap, PE