The influence of PS nanoparticle on dielectric properties of LLDPE

Nanoparticles (NPs), especially inorganic NPs, have been used as fillers to improve the insulation properties of polymers. However, inorganic NPs is difficult to disperse well in polymer matrix, which inhibit the development of insulating nanocomposites for high-voltage direct current power cable. Therefore, it is necessary to improve the dispersion of NPs in the polymer matrix in order to make NPs play a greater role. In this work, polystyrene NPs (PS-NPs) were synthesized and used as fillers to improve the insulation properties of LLDPE. SEM images show that PS-NPs are monodispersed in LLDPE matrix without thermal fusion when the content of PS-NPs is less than 1 wt%. The results of DSC illustrate that the addition of PS-NPs had no effected on thermal behavior of LLDPE. With the introduction of PS-NPs, the DC breakdown strength of LLDPE/PS-NPs is first increased and then decreased. The highest value of 346.5 kV/mm is obtained by PS-0.1 with 0.1 wt% of PS-NPs. The electric conductivity of all LLDPE/PS-NPs composites are decreased comparing with neat LLDPE. Meanwhile, PS-NPs had no significant influence on the dielectric permittivity and dielectric loss of the complex. Therefore, PS-NPs is an alternative option to improve the insulating performance, and our results provide a way for the development of nanocomposites insulating material.