Preparation and properties of poly(ethylene terephthalate)/silica nanocomposites

A kind of poly(ethylene terephthalate) (PET)/Silica nanocomposite (PETS) was synthesized via in situ polymerization using the compatibility between silica nanoparticles and ethylene glycol (EG). Transmission electron microscopy (TEM) micrographs revealed that the silica nanoparticles were well dispersed in the PET matrix, the particle size was about 10 nm with narrow distribution, and there existed strong interaction between the particles and the polymer chains. Differential scanning calorimetry (DSC) results indicated that the thermal properties of PETS with 2 wt% silica (PETS-2) are different from those of pure PET (PETS-0). The properties of the as-spun fibers show that the tenacity and LASE-5 (load at a specified elongation of 5%) of PETS-2 were higher than those of PETS-0, while the heat shrinkage of PETS-2 was lower than that of PETS-0. We suggest that the increasing of crystallinity and the strong interface interaction of the nanocomposite caused the fibers of PETS-2 to not only have higher tenacity and LASE-5 but also to have lower heat shrinkage.