Electrical, thermal and mechanical properties of iodine-doped highly elongated ultrahigh molecular weight polyethylene films filled with multiwalled carbon nanotubes

Highly elongated ultrahigh molecular weight polyethylene (UHMWPE) films filled with multiwalled carbon nanatubes (MWNTs) prepared by gelation/crystallization from solution, were doped by iodine. The electrical conductivity of iodine-doped MWNTs-UHMWPE film was about two to four orders of magnitude higher than that of original films, and the conductivity became stable and orderly in the temperature range of 25 degrees C to 150 degrees C after iodine-doping. Raman spectrum results indicated that the doped iodine as (I-5(-)) existed in the drawn MWNTs-UHMWPE film, which leaded to an increase in the electrical conductivity. The iodine-doping caused the decrease in the crystallinity of UHMWPE, which is confirmed by differential scanning calorimetry. The storage modulus of the doped film was still kept as high as that of the original film. At the room temperature, the storage modulus of the iodine-doped film reached 42GPa.