Benzylaminofullerene (BAF, [C60H4.7(NHCH2C6H5)4.7])/low-density polyethylene (LDPE) composites containing up to 10 wt.% BAF have been prepared from solution. BAF is evenly distributed as small articles of 1-5 mum in polyethylene (PE). The BAF particles do not aggregate even when PE was heated to melt. The dielectric permittivity and loss factor have been studied as a function of BAF loading and frequency. The composites have almost same small dielectric loss as LDPE partly due to the volume increase after mixing. The composite materials have been characterized by optical microscopy, X-ray diffraction, dynamic mechanical and thermal mechanical techniques. The introduction of BAF does not affect the crystal structure and the crystallinity of PE, indicating that BAF is distributed in the amorphous region of PE. The composites show higher storage modulus and loss modulus than LDPE; but higher BAF loading has adverse effect on the modulus. (C) 2001 Elsevier Science Ltd. All rights reserved.