In the present paper cross-linked polyethylene/organic montmorillonite (XLPE/O-MMT) nanocomposites

in which organic montmorillonite (O-MMT) treated by octadecyl ammonium chloride as the inorganic nanophase

low density polyethylene(LDPE) as the matrix polymer

maleic anhydride grafted polyethylene (PEMA) as the compatibilizer and bis(1-(tert-butylperoxy)-1-methylethyl)-benzene (BIPB) as the crosslinking agent

are prepared by means of the two-step method

i.e.after melting intercalation process the cross-linking reaction is carried out chemically.The space charge properties of XLPE/O-MMT nanocomposites with different proportions of O-MMT are investigated by the pulsed electro-acoustic (PEA) method.The test results indicate that XLPE/O-MMT nanocomposites with certain content of O-MMT reveal the ability inhibiting space charge in different degrees compared with XLPE.In XLPE/O-MMT nanocomposites there is the lowest space charge amount when O-MMT content is 0.5 wt%~1 wt% and the space charge amount increases with O-MMT content in the range of 3 wt%~7 wt%

but it is still lower than that of XLPE.It is proved by the thermally stimulated current (TSC) tests that the TSC peak of XLPE/O-MMT nanocomposites shifts to higher temperatures compared with that of XLPE

and it is suggested that the traps depth increases.The area under TSC curve of XLPE/O-MMT nanocomposite with 1 wt% O-MMT is the least

accordingly its traps density is also the lowest; and the areas under TSC curves of XLPE/O-MMT nanocomposites increase with O-MMT content increasing

it means traps density enhancing.The test results of insulation electrical conductivity support the above conceptions further.