Multiwalled carbon nanotubes (MWCNTs) were incorporated in low density polyethylene (LDPE)/ polyolefin elastomer (POE) (mass ratio: 70 : 30) blends by melt compounding. The morphology, electrical, mechanical and rheological properties as well as crystallisation behaviour of LDPE/POE/ MWCNTs composites were studied. The dispersion of MWCNTs in the matrix was observed by scanning electron microscopy. MWCNTs had a nucleating effect on LDPE/POE blends without influencing the crystal structure of composites, as shown by X-ray diffraction. The network of MWCNTs formed with the increasing content of MWCNTs, leading to the change in electrical resistivity and decrease in melt flowrate. There was percolation threshold existed in electrical resistivity. As content of MWCNT was 10 wt-% in composite, the volume and surface resistivity of composites largely decreased; meanwhile, the dielectric constant of composite increased dramatically. The mechanical properties of composites decreased as the content of MWCNTs increased.

Ethylene-propylene-diene monomer (EPDM) rubber composites reinforced with 50 phr samarium oxide (Sm 2 O 3 ), samarium borate (SmBO 3 ) and Sb in antimony doped tin oxide (ATO) are aged at 150uC for different intervals. It is found that neutral Sm 2 O 3 and alkaline SmBO 3 can retard the oxidative degradation of EPDM by blocking radical passage. The acidic ATO particles can accelerate the oxidative degradation of EPDM. The trend of tensile strength of EPDM composites is consistent with that of cross-link density of EPDM composites. SmBO 3 and ATO can retard the increase of dielectric loss until 10 days of aging, while Sm 2 O 3 can keep the dielectric loss at low level until 14 days of aging. The increased surface charge of filler can make surface and volume resistivity decrease sharply. Antimony doped tin oxide can deteriorate the dielectric strength of EPDM, while SmBO 3 and Sm 2 O 3 can keep the dielectric strength of EPDM at a constant level.