Non-crosslinked Semi-conductive Outer Shielded Cable Material

At present,most of the medium and high voltage cables widely used at home and abroad are crosslinked polyolefin materials,and the semiconductive outer shield material is basically a crosslinked polyolefin thermoplastic elastomer.However,cross-linked polyolefin materials are not easy to recycle and use after they reach the end of their working life,which is not conducive to environmental protection.Therefore,the current medium and high voltage non-crosslinked cable materials have become the focus of research.The intermediate and high voltage non-crosslinked insulation materials represented by PP have made important progress.However,the non-crosslinked semi-conductive outer shielding materials that are matched with them are rarely reported.Based on this,this paper studies the non-crosslinked semi-conductive shielding material,laying a good foundation for the industrialization of medium and high voltage noncrosslinked cables.In this paper,the TPU / PP-g-MAH type,TPU / PP-g-MAH type semiconductive shielding materials were firstly studied and tested by thermal elongation and peel test.Non-crosslinked semi-conductive outer shield basic resin system.The influence of the amount of TPU added on the performance of the noncrosslinked semi-conductive outer shielding material of TPU/CB/PP-g-MAH was studied.The peelability,conductivity,tensile properties,scanning electron microscopy,X-ray diffraction,etc.were tested and analyzed..The results show that with the increase of TPU,the peeling force gradually decreases,and the tensile strength,elongation at break and elastic modulus increase first and then decrease,the volume resistivity shows a slightly upward trend,and the thermal elongation of the composite material increases.Gradually become larger;when the TPU content reaches 62.5 wt%,the peel force is 18.2 N/2cm;the tensile strength reaches 14.8 MPa,the elongation at break reaches 343%;the volume resistivity reaches 82 ?·m,and the thermal elongation of the composite material The long rate is 12% and the permanent deformation rate is 7%.At the same time,the influence of the content of conductive carbon black under the two ratios(weight ratio of PP-g-MAH and TPU is 5:3 and 1:1)on the main properties of the semi-conductive outer shielding material was comparatively studied.The results show that with the increase of the content of conductive carbon black,the changes of the volume resistivity and the peeling performance of the two formulations are basically the same,the volume resistivity decreases first and then increases,and the peeling force increases first and then decreases.When the content of conductive carbon black is 37 wt % at room temperature,when the ratio of PP-g-MAH to TPU is 5:3,the volume resistivity of the material can reach 62.5 ?·m,and the release force reaches 15.8 N/2cm;PP-When the ratio of g-MAH to TPU is 1:1,the volume resistivity of the material can reach 58.5 ?·m and the peel force can reach 17.8 N/2cm.The ratio of 5:3 is better than 1:1,while the performance analysis of semi-conductive external shielding material with resin ratio of 5:3 shows that the breaking energy and elongation at break decrease with the increase of carbon black content.The trend shows that the tensile strength increases first and then decreases.At 165 °C,the load elongation shows a trend of increasing first and then decreasing.The blending torque of the material decreases and the blending time is shortened;the carbon black content is At 37 wt%,the elongation at break was 402%,the tensile strength was 15.6 MPa,the thermal elongation was 5%,and the permanent set rate was 4%.