Crystal growth in alumina/poly(ethylene terephthalate) nanocomposite films |
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Authors: | Hoichang Yang Praveen Bhimaraj Lin Yang Richard W Siegel Linda S Schadler |
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Institution: | 1. Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180;2. Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180;3. National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973;4. Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180;5. Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180 |
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Abstract: | The crystal growth and morphology in 150‐nm‐thick PET nanocomposite thin films with alumina (Al2O3) nanoparticle fillers (38 nm size) were investigated for nanoparticle loadings from 0 to 5 wt %. Transmission electron microscopy of the films showed that at 1 wt % Al2O3, the nanoparticles were well dispersed in the film and the average size was close to the reported 38 nm. Above 2 wt % Al2O3, the nanoparticles started to agglomerate. The crystal growth and morphological evolution in the PET nanocomposite films kept at an isothermal temperature of 217 °C were monitored as a function of the holding time using in situ atomic force microscopy. It was found that the crystal nucleation and growth of PET was strongly dependent on the dispersed particles in the films. At 1 wt % Al2O3, the overall crystal growth rate of PET lamellae was slower than that of the PET homopolymer films. Above 2 wt % Al2O3, the crystal growth rate increased with nanoparticle loading because of heterogeneous nucleation. In addition, in these PET nanocomposite thin films, the Al2O3 nanoparticles induced preferentially oriented edge‐on lamellae with respect to the surface, which was not the case in unfilled PET as determined by grazing‐incidence X‐ray diffraction. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 747–757, 2007 |
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Keywords: | alumina (Al2O3) crystallization grazing‐incidence X‐ray diffraction nanocomposites polyesters poly(ethylene terephthalate) (PET) thin film WAXS |
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