Study On Enhancement Of Insulating Properties Of Polyethylene Blends By Electron Donor-Acceptor Type Voltage Stabilizer

Compared with cross-linked polyethylene,polyethylene blends have the characteristics of no cross-linked by-products and easy recovery,so it has attracted more and more attention as a new type of cable material.In order to develop a new environment friendly cable and improve its insulation performance,this paper selects low-density polyethylene and high-density polyethylene as the base material,and selects four electron donor-acceptor type voltage stabilizers,m-aminobenzoic acid,2-methoxy-5-pyridyl boric acid,m-aminobenzoic acid and 4-dimethylaminobenzoic acid,added to the polyethylene blend.The physical and chemical properties and electrical properties of polyethylene blends were analyzed,and the effect of electron donoracceptor type voltage stabilizers on the electrical properties of polyethylene blends was studied.The electron donor-acceptor type voltage stabilizers / polyethylene blends were prepared by solution method.The physical and chemical properties of the blends were analyzed by Fourier infrared spectroscopy,X-ray diffraction,thermo-gravimetry analysis and differential scanning calorimetry.The electrical tree initial voltage of the blends was measured by the real-time observation of the electrical tree and the synchronous measurement system of partial discharge.The conductivity of the blends was measured by the conductivity measurement system;the space charge distribution of the blends was measured by the pulse electro-acoustic space charge measurement system;the surface potential decay and trap characteristics of the blends were measured by the surface potential decay measurement system,and the electrical insulation performance of the electron donor-acceptor type voltage stabilizers / polyethylene blends was studied.The results of physical and chemical analysis showed that after the preparation of the material by solution method,four kinds of electron donor-acceptor type voltage stabilizers were successfully added into the polyethylene blend.The addition of voltage stabilizers was conducive to the crystallization of the material,the crystallinity of the blend was improved,the thermal stability was improved,and the effect of the voltage stabilizers on the melting characteristics of the blend was not significant.The electrical properties of the blends were tested.The results showed that the electrical tree initial voltage increased significantly when voltage stabilizer was added to the blends,and the highest electrical tree initial voltage was found in m-aminobenzoic acid / polyethylene blends.The conductivity of the blends was different when voltage stabilizer was added,and the conductivity of the blends was obvious decreased when m-aminobenzoic acid was added.The space charge in the blends was suppressed by voltage stabilizer,among which m-aminobenzoic acid and m-aminobenzoic acid had the best effect.Quantum chemical calculation shows that the selected electron donor-acceptor type voltage stabilizers has a small HOMO-LUMO energy gap,which has the ability to buffer highenergy electrons;the theoretical calculation of trap energy level shows that the trap of polyethylene blends becomes shallow after adding electron donor-acceptor type voltage stabilizers,which is beneficial to the charge debonding,thus suppressing the accumulation of space charge in the materials.