TY - JOUR
T1 - P(VDF-TrFE)-layered silicate nanocomposites. Part 1. X-ray scattering and thermal analysis studies
AU - Cebe, Peggy
AU - Runt, James
N1 - Funding Information:
The authors express their appreciation to the National Science Foundation, Polymers Program (DMR—0100646 and DMR—0211056) for partial support of this research. We thank Tufts undergraduate students, Ms Heather Held and Ms Megan Peal for assistance with thermal analysis, and Ms Laurel Powers for assistance with X-ray diffraction. We would also like to thank Mr Rob J. Klein for helpful discussions.
PY - 2004/3
Y1 - 2004/3
N2 - X-ray scattering and thermal analyses were used to investigate the effects of organically modified layered silicates (OMS) on the paraelectric and ferroelectric phase transitions in poly(vinylidene fluoride-co- trifluoroethylene) [P(VDF-TrFE)]/OMS nanocomposites. Nanocomposites comprising a 75/25 P(VDF-TrFE) random co-polymer with either Nanomer I.30TC or Lucentite STN OMS were prepared with compositions ranging from 2 to 25wt% OMS. Wide-angle X-ray scattering (WAXS) studies show that the silicate gallery spacing increases modestly in the nanocomposites compared to the neat OMS powder, indicating a level of co-polymer intercalation. Thermogravimetric analysis indicates that thermal stability is improved in nanocomposites with higher OMS contents: they have substantial increase in weight remaining, both at 500°C and at 1000°C, compared to that predicted from the behavior of the neat co-polymer and OMS. Differential scanning calorimetry (DSC) and WAXS results show that thermal transitions in the nanocomposites depend on OMS content. Nanocomposites with 2% OMS exhibited a crystal nucleating effect, which results in significant increase in the amount of ferroelectric crystals formed during cooling. For greater OMS additions (10-25%), the amounts of para- and ferroelectric crystals are reduced. The larger OMS additions depress the melt-to-paraelectric transition temperature, while an increase in the paraelectric-to-ferroelectric transition temperature is observed for all compositions. Upon reheating, the ferroelectric phase transition shows significant hysteresis. We conclude that the addition of either Lucentite or Nanomer OMS to 75/25 P(VDF-TrFE) causes an increase in the temperature stability range for the ferroelectric phase.
AB - X-ray scattering and thermal analyses were used to investigate the effects of organically modified layered silicates (OMS) on the paraelectric and ferroelectric phase transitions in poly(vinylidene fluoride-co- trifluoroethylene) [P(VDF-TrFE)]/OMS nanocomposites. Nanocomposites comprising a 75/25 P(VDF-TrFE) random co-polymer with either Nanomer I.30TC or Lucentite STN OMS were prepared with compositions ranging from 2 to 25wt% OMS. Wide-angle X-ray scattering (WAXS) studies show that the silicate gallery spacing increases modestly in the nanocomposites compared to the neat OMS powder, indicating a level of co-polymer intercalation. Thermogravimetric analysis indicates that thermal stability is improved in nanocomposites with higher OMS contents: they have substantial increase in weight remaining, both at 500°C and at 1000°C, compared to that predicted from the behavior of the neat co-polymer and OMS. Differential scanning calorimetry (DSC) and WAXS results show that thermal transitions in the nanocomposites depend on OMS content. Nanocomposites with 2% OMS exhibited a crystal nucleating effect, which results in significant increase in the amount of ferroelectric crystals formed during cooling. For greater OMS additions (10-25%), the amounts of para- and ferroelectric crystals are reduced. The larger OMS additions depress the melt-to-paraelectric transition temperature, while an increase in the paraelectric-to-ferroelectric transition temperature is observed for all compositions. Upon reheating, the ferroelectric phase transition shows significant hysteresis. We conclude that the addition of either Lucentite or Nanomer OMS to 75/25 P(VDF-TrFE) causes an increase in the temperature stability range for the ferroelectric phase.
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U2 - 10.1016/j.polymer.2004.01.014
DO - 10.1016/j.polymer.2004.01.014
M3 - Article
AN - SCOPUS:1242328726
SN - 0032-3861
VL - 45
SP - 1923
EP - 1932
JO - Polymer
JF - Polymer
IS - 6
ER -