Carbon nanotubes induced nonisothermal crystallization of ultrahigh molecular weight polyethylene with reduced chain entanglements

The semicrystalline ultrahigh molecular weight polyethylene (UHMWPE) gel film containing 1.0 wt% multiwalled carbon nanotubes (MWNTs) was prepared by the gelation/crystallization technique. The effect of carbon nanotubes on the nonisothermal crystallization of UHMWPE was investigated by differential scanning calorimetry (DSC). The crystallization rate, characterized by half crystallization time (t(1/2)), of the UHMWPE/MWNTs gel film is lower than that of UHMWPE at the same cooling rate, especially at lower cooling rate, indicating high nucleation ability of MWNTs in UHMWPE. However, the onset and maximum crystallization temperatures for the UHMWPE/MWNTs gel film are almost the same as that for UHMWPE at the same cooling rate, this result from the confinement of UHMWPE chains on the surfaces of MWNTs which withheld the growth of nuclei. (c) 2012 Elsevier B.V. All rights reserved.