Study On The Electrical Properties Of Polyethylene/Nanoparticles Composites

Polymer materials has been widely used in high-voltage direct-current?HDVC?insulation equipment,Polymer materials can produce electrical aging and decrease electric breakdown strength which affects its performance for a long time.This article uses the method that is filled with inorganic nanoparticles to compound polymer nanocomposites and study its performance.Firstly,the LLDPE-g-PS was synthesized by pre-irradiation technique and suspension graft copolymerization.FTIR was used to analyze the structure of LLDPE-g-PS and grafting rate is 17.2% by desiccant method.The results showed that St has been successfully grafted onto LLDPE.Preparation of PS content respectively is 5 wt%,10 wt%,15 wt%,20 wt% of LLDPE/LLDPE-g-PS composites,scanning electron microscopy?SEM?analysis of LLDPE-g-PS has the effect of solubilizer,improve the interaction of LLDPE and PS.Through electronic tensile machine for testing the tensile strength and elongation at break,when content 5 wt% of PS,tensile strength is 19.3 MPa,the elongation at break is 1232.4%.DSC and TGA prove that materials are stable,XRD shows crystal shape does not change.Dielectric performance test showed that volume resistivity enhances improve an order of magnitude.There is a decrease in the dielectric constant and dielectric loss.When content 10 wt% of PS,breakdown voltage is increased by 10 kV/mm.Using grafting method and silane coupling agent method modified for MgO nanoparticles surface.The elements of MgO-g-PS grafting rate are analysised,including Monomer concentration of St,MgO with St matching and reaction temperature.Getting the best condition of MgO-g-PS:0.12 mol/L of monomer concentration,MgO: St is 1/1.8?wt/wt?,85 ? of the reaction temperature.Fourier transform infrared spectrum shows a new peak at 1628 cm-1?C = C double bond stretching vibration peak on nano surface grafting styrene in benzene ring?,TEM reveals nanoparticle agglomerates phenomenon has been improved.At the same time,Al₂O₃ surface is modified.LLDPE and MgO-g-PS are fabricated by melt blending by mixer,the preparation of nanoparticle content is 10 wt% masterbatch?Masterbatch,LLDPE and LLDPE-g-PS blend,respectively,the preparation of nanoparticle content was 0.5 wt%,1.0 wt%,1.5 wt% and 0.5 wt%,PS content is 10 wt% of LLDPE/LLDPE-g-PS/MgO-g-PS.Scanning electron microscopy?SEM?figures show nanoparticle good dispersed in the matrix size at around 100 nm.Through electronic tensile machine for testing the tensile strength and elongation at break,when content 1.5 wt% of nanoparticle,LLDPE/LLDPE-g-PS/MgO-g-PS tensile strength is 12.4 MPa,the elongation at break is 572.4 %.DSC and TGA prove that nanocomposites is stable,XRD shows crystal shape does not change.Dielectric performance test showed that volume resistivity enhances improve an order of magnitude Dielectric constant increases by 0.15 and breakdown voltage increases 10 kV/mm.That MgO add is helpful to improve the insulation of the material properties.At the same time,Al₂O₃ nanoparticles composites were prepared.