Poly(ethylene terephthalate) nanocomposite fibers with functionalized multiwalled carbon nanotubes via in-situ polymerization

Poly(ethylene terephthalate) (PET) hybrids with newly synthesized functionalized multiwalled carbon nanotubes (MWNTs) were obtained by carrying out the in situ polycondensation of ethylene glycol with dimethyl terephthalic acid. The PET hybrids were melt-spun to produce monofilaments with various functionalized MWNT contents and draw ratios (DRs). The thermomechanical properties and morphologies of the PET hybrid fibers were determined using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide angle X-ray diffraction (XRD), electron microscopy (SEM and TEM), and a universal tensile machine (UTM). The XRD analysis and TEM micrographs show that the levels of nanosize dispersion can be controlled by varying the MWNT content. It was found that the addition of only a small amount of functionalized MWNTs was sufficient to improve the properties of the PET hybrid fibers. The maximum enhancement in the ultimate tensile strength was found to arise at a functionalized MWNT content of 0.5 wt %. However, the initial modulus was found to increase linearly with increases in the functionalized MWNT loading from 0 to 1.5 wt %. The thermal properties and conductivities of the PET hybrid fibers were found to be better than those of pure PET fibers. (c) 2008 Wiley Periodicals, Inc.