DISPERSION AND NUCLEATION FOR ULTRAFINE PARTICLES OF SILICA AND SILICATE IN POLY（ETHYLENE TEREPHTHALATE） BASED COMPOSITES

In this paper,the dispersion and nucleation behavior of ultrafine particles of silica and layered silicate (LS) in poly(ethylene terephthalate) (PET) matrix are investigated and characterized by Transmission Electron Microscopy (TEM),Wide Angle X-ray Diffraction (WAXD),Dynamic Scanning Calorimetry (DSC),and Atomic Force Microscopy (AFM).The solid precursors based on silica and LS are suggested originally for preparing nanocomposites with good dispersion morphology.Results show that the initial sub-micron (1000-500nm) LS particles are exfoliated or dispersed into nanometer-scale particles (30-70nm) during their polymerization with PET monomers.These dispersed nanoparticles form an ordered morphology in their nucleation and growth during annealing nanocomposites.DSC patterns reveal that the double melting peaks of annealed PET-LS nanocomposites disappear,while they have shrunken in PET-silica ones.These findings strongly demonstrate that the dispersed nanoparticles accelerate the crystallization of PET.The dispersed LS particles have higher percolation and nucleation performance than those of silica.The homogeneous distribution morphology of ultrafine particles is easily obtained by controlling the load of their corresponding precursors.Such a dispersion obviously improves PET properties in that its heat distortion temperature (HDT)increases from 76℃ to 103℃, and crystallization increases 2-4 times more than that of PET.Especially,the nanocomposite films keep themselves transparent when particle load is within 2 wt.% though there are 3 wt.% or so of agglomerated particles in the nanocomposites.

DISPERSION AND NUCLEATION FOR ULTRAFINE PARTICLES OF SILICA AND SILICATE IN POLY(ETHYLENE TEREPHTHALATE) BASED COMPOSITES

In this paper, the dispersion and nucleation behavior of ultrafine particles of silica and layered silicate (LS)in poly(ethylene terephthalate) (PET) matrix are investigated and characterized by Transmission Electron Microscopy(TEM), Wide Angle X-ray Diffraction (WAXD), Dynamic Scanning Calorimetry (DSC), and Atomic Force Microscopy(AFM). The solid precursors based on silica and LS are suggested originally for preparing nanocomposites with good dispersion morphology. Results show that the initial sub-micron (1000～500 nm) LS particles are exfoliated or dispersed into nanometer-scale particles (30～70 nm) during their polymerization with PET monomers. These dispersed nanoparticles form an ordered morphology in their nucleation and growth during annealing nanocomposites. DSC patterns reveal that the double melting peaks of annealed PET-LS nanocomposites disappear, while they have shrunken in PET-silica ones. These findings strongly demonstrate that the dispersed nanoparticles accelerate the crystallization of PET. The dispersed LS particles have higher percolation and nucleation performance than those of silica.The homogeneous distribution morphology of ultrafine particles is easily obtained by controlling the load of their corresponding precursors. Such a dispersion obviously improves PET properties in that its heat distortion temperature (HDT)increases from 76℃ to 103℃, and crystallization increases 2～4 times more than that of PET. Especially, the nanocomposite films keep themselves transparent when particle load is within 2 wt.% though there are 3 wt.% or so of agglomerated particles in the nanocomposites.