Study of montmorillonite on morphology and water treeing behavior in crosslinking polyethylene

Water trees would be initiated and developed easily in crosslinking polyethylene for long-time operating power cable under high electrical field with residual moisture in it, which results in the insulation breakdown. In this paper, a series of MMT/XLPE nano-composites are prepared though melting blend method. Organic modifier is used to control the dispersion state of MMT in XLPE. The results of SEM and X-Ray show that the interlayer space of MMT is in nanometer and polyethylene chains could be intercalary in MMT. DSC results show that the crystallization morphology of XLPE could be improved by MMT particles. Accelerating water tree ageing tests are performed on nano-composites. The results show that water tree length is reduced in nano-composites comparing with pure XLPE. This indicates that MMT particle could restrain the growth of water tree by modifying the morphology of XLPE.