Dielectric spectra properties of Low-density polyethylene(LDPE) / zeolite nanoscale composite

Use type 4A nanoscale zeolite powder composite with Low-density polyethylene(LDPE), obtained the different of doping concentration of composite materials which the zeolite weight percentage are from 0.5wt% to 3wt%. By using broadband dielectric spectrometer measure and analyse the dielectric performance in a relatively wide frequency range to LDPE/zeolite composite and pure polyethylene at different temperature (293K, 323K and 353K). The test results show that, with the increase of the concentration of the doping, the LDPE/zeolite composite materials' dielectric constant gradually declined, until below 2.0 when the zeolite weight percentage was 3wt% at 293K. Because zeolite material has a framework of silicon, oxygen and aluminum with porous structure, the empty space in the framework make the dielectric constant of LDPE/zeolite composite reduced. When the temperature rise to 323K and 353K the dielectric constant of LDPE/zeolite composite and pure polyethylene are on a declining curve. The dielectric constant goes to 1.85 when the zeolite weight percentage was 3wt% at 353K and the frequency is 10⁶Hz. At the same time, dielectric losses of the composite material also have obvious changes, in the low frequency area dielectric loss of LDPE/zeolite composite decrease in 10 ^-2∼1Hz area and are lower the pure polyethylene. In the 10 ¹ ∼ 10⁴Hz area, the dielectric losses of LDPE/zeolite composite have a peak in all the samples. When the frequency is more than 105Hz, the dielectric losses are on the rise. This kind of phenomenon can be also concerned with the framework of zeolite within the LDPE/zeolite composite. This new type of composite material keeps the same performance of polyethylene, reduce the dielectric constant and change the dielectric loss features will contribute to improve the breakdown strength of materials.