Dielectric and AC Breakdown Properties of SiO2/MMT/LDPE Micro–Nano Composites

Abstract

Low-density polyethylene (LDPE) is an important thermoplastic material which can be made into films, containers, wires, cables, etc. It is highly valued in the fields of packaging, medicine, and health, as well as cables. The method of improving the dielectric property of materials by blending LDPE with inorganic particles as filler has been paid much attention by researchers. In this paper, low-density polyethylene is used as the matrix, and montmorillonite (MMT) particles and silica (SiO2) particles are selected as micro and nano fillers, respectively. In changing the order of adding two kinds of particles, a total of five composite materials were prepared. The crystallization behavior and crystallinity of five kinds of composites were observed, the εr and tanδ changes of each material were investigated with frequency and temperature, and the power frequency (50 Hz) AC breakdown performance of materials were measured. The differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results show that the crystallinity of the composites is higher than that of LDPE. Experimental data of dielectric frequency spectra show that the dielectric constants of micro–nano composites and composites with added MMT particles are lower than LDPE, the dielectric loss of composites can be improved by adding MMT particles. The experimental data of dielectric temperature spectra show that the permittivity of SiO2-MMT/LDPE is still at a low level under the condition of 20~100 °C. In terms of breakdown field strength, the SiO2/LDPE composite material increased by about 17% compared with the matrix LDPE, and the breakdown field strength of the materials SiO2-MMT/LDPE and MMT-SiO2/LDPE increased by about 6.8% and 4.6%, respectively.

Exploring the reinforcing mechanism and micromechanical models for the interphase characteristics in melt mixed XLPE‐fumed SiO2 nanocomposites

“…When SiO 2 particles are added to XLPE, they will form many interfaces in the XLPE nanocomposites. The electrical fields change gradually faster when increasing the frequency; therefore, the relaxation polarization is too slow to keep abreast of the electrical fields 64,65 . In addition to the interface formations, SiO 2 was effectively trapped in the XLPE matrix, forming a well‐established network structure in XLPE nanocomposites, as shown in Figures 6b and 9.…”

“…The electrical fields change gradually faster when increasing the frequency; therefore, the relaxation polarization is too slow to keep abreast of the electrical fields. 64,65 In addition to the interface formations, SiO 2 was effectively trapped in the XLPE matrix, 6b and 9. Four basic polarization mechanisms exist in response to the applied electric field, that is, interface polarization, electronic polarization, ionic polarization, and orientation polarization.…”

Design of HDPE‐based nanocomposite with excellent thermal‐oxidative aging resistance, mechanical properties and electrical insulation properties: Dispersing nano‐ZnO assisted by natural rubber latex

“…The samples were cut into discs of 50 mm diameter. In order to prevent edge discharge of metal electrodes, both samples and tested electrodes were immersed in cable oil 31 . Before testing, the thickness of the sample was first measured with a thickness gauge, and then it was placed on the test bench and tested at a boosting speed of 2 kV s −1 until the sample broke.…”

Optimal Design of Functionally Graded Power Cable Joint Utilizing Silicone Rubber/Carbon Nanotube Composites

“…The breakdown test was conducted under AC voltage, in which the voltage increased at a rate of 1 kV/s until breakdown occurred. For each type of specimen, the Eb test was repeated more than 15 times, and two-parameter Weibull statistics [12] were used to analyze the data.…”