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Title: Crystal Growth in Alumina/poly(ethylene terephthalate) Nanocomposite Films

Abstract

The crystal growth and morphology in 150-nm-thick PET nanocomposite thin films with alumina (Al{sub 2}O{sub 3}) 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% Al{sub 2}O{sub 3}, the nanoparticles were well dispersed in the film and the average size was close to the reported 38 nm. Above 2 wt% Al{sub 2}O{sub 3}, 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% Al{sub 2}O{sub 3}, the overall crystal growth rate of PET lamellae was slower than that of the PET homopolymer films. Above 2 wt% Al{sub 2}O{sub 3}, the crystal growth rate increased with nanoparticle loading because of heterogeneous nucleation. In addition, in these PET nanocomposite thin films, the Al{sub 2}O{sub 3} nanoparticles induced preferentially oriented edge-on lamellae with respect to the surface, which was not the case inmore » unfilled PET as determined by grazing-incidence X-ray diffraction.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
929872
Report Number(s):
BNL-80444-2008-JA
TRN: US200822%%922
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Polymer Science Part B: Polymer Physics; Journal Volume: 45; Journal Issue: 7
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CRYSTAL GROWTH; MORPHOLOGY; ALUMINIUM OXIDES; POLYETHYLENES; LAMELLAE; NUCLEATION; PARTICLE SIZE; THIN FILMS; COMPOSITE MATERIALS; NANOSTRUCTURES; national synchrotron light source

Citation Formats

Yang,H., Bhimaraj, P., Yang, L., Siegel, R., and Schadler, L. Crystal Growth in Alumina/poly(ethylene terephthalate) Nanocomposite Films. United States: N. p., 2007. Web. doi:10.1002/polb.21096.
Yang,H., Bhimaraj, P., Yang, L., Siegel, R., & Schadler, L. Crystal Growth in Alumina/poly(ethylene terephthalate) Nanocomposite Films. United States. doi:10.1002/polb.21096.
Yang,H., Bhimaraj, P., Yang, L., Siegel, R., and Schadler, L. Mon . "Crystal Growth in Alumina/poly(ethylene terephthalate) Nanocomposite Films". United States. doi:10.1002/polb.21096.
@article{osti_929872,
title = {Crystal Growth in Alumina/poly(ethylene terephthalate) Nanocomposite Films},
author = {Yang,H. and Bhimaraj, P. and Yang, L. and Siegel, R. and Schadler, L.},
abstractNote = {The crystal growth and morphology in 150-nm-thick PET nanocomposite thin films with alumina (Al{sub 2}O{sub 3}) 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% Al{sub 2}O{sub 3}, the nanoparticles were well dispersed in the film and the average size was close to the reported 38 nm. Above 2 wt% Al{sub 2}O{sub 3}, 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% Al{sub 2}O{sub 3}, the overall crystal growth rate of PET lamellae was slower than that of the PET homopolymer films. Above 2 wt% Al{sub 2}O{sub 3}, the crystal growth rate increased with nanoparticle loading because of heterogeneous nucleation. In addition, in these PET nanocomposite thin films, the Al{sub 2}O{sub 3} 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.},
doi = {10.1002/polb.21096},
journal = {Journal of Polymer Science Part B: Polymer Physics},
number = 7,
volume = 45,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Polymer nanocomposites based on metal oxide (ceramic) nanoparticles are a new class of materials with unique properties and designed for various applications such as electronic device packaging, insulation, fabrication and automotive industries. Poly(ethylene terephthalate) (PET)/alumina (Al{sub 2}O{sub 3}) nanocomposites with filler content between 1 wt% and 5 wt% were prepared by melt compounding method using co-rotating twin screw extruder and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and precision LCR meter techniques. The results revealed that proper uniform dispersion at lower content up to 2 wt% of nano-alumina observed by using TEM. Aggregation of nanoparticles was observedmore » at higher content of alumina examined by using SEM and TEM. The frequency dependences of the alternating current (AC) conductivity (σ{sub AC}) of PET/alumina nanocomposites on the filler content and DC bias were investigated in the frequency range of 20Hz - 1MHz. The results showed that the AC and direct current (DC) conductivity increases with increasing DC bias and nano-alumina content upto 3 wt%. It follows the Jonscher’s universal power law of solids. It revealed that σ{sub AC} of PET/alumina nanocomposites can be well characterized by the DC conductivity (σ{sub DC}), critical frequency (ω{sub c}), critical exponent of the power law (s). Roll of DC bias potential led to an increase of DC conductivity (σ{sub DC}) due to the creation of additional conducting paths with the polymer nanocomposites and percolation behavior achieved through co-continuous morphology.« less
  • Full-pattern fiber X-ray diffraction refinement has been used to study the structure and morphology of the crystallites of three poly(ethylene terephthalate) fiber samples with different heat treatment history. Diffraction data over the whole two-dimensional space were collected with a four-circle diffractometer. An iterative Fourier filter method is developed to separate the crystalline diffraction from the background scattering. Both the structure and morphology are found to be dependent on the heat treatment. Some properties of the fibers can be explained by the difference in the crystal structure and morphology of crystallites.
  • The surfaces of poly(ethylene terephthalate) obtained by irradiation with the 193-nm pulsed radiation of the ArF excimer laser (10/sup 7/ W/cm/sup 2/) in air or the 185-nm low-intensity (2.5 mW/cm/sup 2/) radiation of the mercury lamp in a vacuum were studied and compared. The XPS analysis reveals that both are depleted in oxygen, but the efficiency of the change is intensity dependent as a result of nonlinear effects at high intensity. The pulsed radiation, which gives ablative photodecomposition when the energy of the pulse is > 40 mJ/cm/sup 2/, yields a rough surface. SEM analysis shows that the roughness (i)more » has an amplitude which increases with the accumulation of pulses and reaches a maximum (1-2-..mu..m spacing) at 10 pulses, and (ii) shows some periodicity. Since the chemical composition of the laser-treated surface does not vary with the accumulation of pulses, the increase in the advancing contact angle with water is interpreted as due to roughness. Labeling reactions and XPS have been used to probe the reactivity of the modified surfaces. Carboxylic acids, alcohols, and olefins were qualitatively and quantitatively probed. 33 references, 10 figures, 2 tables.« less
  • The principle of operation of an apparatus developed to study gas permeation through thin films is described, and the measurement method is discussed. Use is made of diffusion theory to obtain an expression for the permeability coefficient as a function of the rate of increase of the pressure in the receiving volume. The activation energy for permeation of helium through PET is determined. The permeability coefficient for helium is found to increase significantly with the range of the implanted protons although the incident charge has been kept constant. The hypothesis of structural modifications of the proton implanted PET seems tomore » be confirmed by small-angle X-ray scattering experiments on the irradiated samples.« less