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Thermal and Dielectric Properties of High Performance Polymer/ZnO
Nanocomposites
Divij Vaishnav and R. K. Goyal
Department of Metallurgy and Materials Science, College of Engineering, Pune (COEP),
Shivajinagar, Pune, PIN – 411005, INDIA
Email: [email protected], www.coep.org.in
Abstract
Zinc oxide (ZnO) filled high performance
poly(aryletherketon) (PAEK) matrix nanocomposites were
studied for the application in electronic applications. The
nanocomposites were prepared using planetary ball milling
process followed by hot pressing. Experimental density of the
nanocomposites was close to those of theoretical density
indicating porosity free samples. Scanning electron
microscopy showed excellent dispersion of nano sized (< 100
nm) ZnO particles into the PAEK matrix. X-ray diffraction
(XRD) confirmed that the size of ZnO crystallites is about 58
nm. Thermogravimetry analyzer (TGA) showed significant
increase in thermal stability and char yield of the
nanocomposites with increasing ZnO content in the matrix.
The dielectric constants of the nanocomposites increased
significantly compared to those of pure PAEK.
Experimental Procedure
Scanning Electron Microscopy Dielectric Properties
Thermogravimetric Analysis (TGA)
Mixing of ZnO nano particles and PAEK
powder with Ball-Milling for 5 h
Drying in Vacuum Oven at 180 °C for 4 h
Compression Molding of Mixed Powders at
350 °C/45 MPa pressure
Nanocomposites Pellets
Characterization
Density XRD SEM
Dielectric
Properties
Thermogravimetry
analysis (TGA)
Experimental Density v/s Theoretical density
(b)
(a)
(a) SEM image of ZnO powder at 20,000×, inset shows SEM
images at 55,000× magnification.
(b) SEM image of 30 wt% ZnO/PAEK nanocomposite at
10,000 ×magnification.
10 15 20 25 30 35 40
Z(002)
Z(011)
P(110)
Inte
nsity (
a.u
.)
Angle (2)
P(012)
P - PAEK
Z- ZnOZ(010)
NC-0
NC-5
NC-10
NC-20
NC-3020 25 30 35 40
Angle (2)
(010)
(002)
(011)XRD of ZnO
X-ray Diffraction (XRD)
The crystallite size of ZnO powder determined by using
Scherrer formula is about 58 nm.
There is not any change in the peak positions of the reflections
for the nanocomposites compared to pure PAEK.
0 2 4 6 8 10
1.3
1.4
1.5
1.6
1.7
Th
eo
reti
ca
l D
en
sit
y (
g/c
c)
Vol.% of nano ZnO in PAEK matrix
Theoretical Density (g/cc)
Experimental Density (g/cc)
The density of the nanocomposites increased with
increasing ZnO content in the matrix.
Experimental density is close to the theoretical density
indicating almost porosity free samples.
0 2 4 6 8 104.0
4.4
4.8
5.2
5.6
6.0
6.4
6.8
7.2
1 MHz
1 kHz
Die
lec
tric
Co
ns
tan
t
Vol.% of nano ZnO in PAEK matrix
(a)
0 2 4 6 8 10
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
Dis
sip
ati
on
Fa
cto
r
Vol.% of nano ZnO in PAEK matrix
1 kHz
1 MHz
(b)
(a) Dielectric constant versus vol% ZnO content for
PAEK/ZnO nanocomposites
(b) Dissipation factor versus vol% ZnO content for
PAEK/ZnO nanocomposites
Dielectric constant of the nanocomposites increased with
increasing ZnO content in the matrix. It decreased slightly
with increasing frequency.
PAEK reinforced with 30 wt% (9 vol%) ZnO
nanocomposites exhibit about 25% increase in dielectric
constant at 1 MHz frequency.
Dissipation factor of the nanocomposite containing 30 wt
% ZnO is slightly higher than that of pure matrix.
200 400 600 800 1000
50
60
70
80
90
100
Re
sid
ua
l W
eig
ht
(%)
Temperature (oC)
NC - 30
NC - 0
NC - 20
NC - 5 NC - 10
Decomposition temperature of the nanocomposites at 10
wt% loss increased from 567 oC for pure PAEK to 582 oC
for 30 wt% nanocomposites.
Char yield at 1000 oC increased from 52 % for the matrix
to 68 % for 30 wt% nanocomposites.
References: 1. R. K. Goyal, A. S. Kapadia, Composites: Part B 2013, 50:135-143.
2. R. K. Goyal, A. N. Tiwari, U. P. Mulik et al. Comp. Sci. Tech. 2007, 67:1802-1812.
3. B. C. Chang, H.M. Akil, R. Nasir, Wear 2013, 297:1120-1127.
4. M. Ahmad et al., Int. J. Mol. Sci. 2012, 13:15640-15652.
5. L. Sim et al., Thermochimica Acta 2005, 43:155-165.
6. M. Singla, R. Sehrawat, R. Nidhi, K. Singh, J. Nanopart. Res. 2011, 13:2109-2116
7. J. Hong, L. Schalder, R. Siegel, E. Martensson, J. Mater Sci. 2006, 41:5810-5814.
Acknowledgement Divij is greatly thankful to Dr. Keki H. Gharda, Chairman and
Managing Director of Gharda Chemicals Limited, India for providing
sponsorship to attend this conference (NanoStruc 2014). Authors also
acknowledge Dr. Mathew Abraham, Polymer Division, Gharda
Chemicals Limited, Thane, (Mumbai) India for supplying G-PAEK
powder for this research and for fruitful discussions. Authors also
thankful to Dr. A. D. Sahasrabudhe, Director, College of Engineering,
Pune.
International Conference on Structural Nano composites (NanoStruc 2014), May 20-21, 2014 held at Madrid, Spain
Materials
Polyaryletherketon (G-PAEK) powder donated by Gharda
Chemicals Ltd was used in as received form as matrix. Zinc
oxide nano powder (< 100 nm) purchased from Sigma Aldrich
was used in as received condition as reinforcement. Its weight
percentage was varied from 0 to 30.
500 550 600 650 700-7
-6
-5
-4
-3
-2
-1
0
Deri
vati
ve W
eig
ht
(mg
/min
)
Temperature (C)
NC-0NC-5
NC-10
NC-20
NC-30
200 400 600 800 1000-8
-7
-6
-5
-4
-3
-2
-1
0
De
riv
ati
ve
We
igh
t (m
g/m
in)
Temperature (o
C)
The maximum decomposition temperature of the
nanocomposites increased slightly with increasing ZnO
content in the matrix.
Decomposition temperature increased from 581 oC for pure
PAEK to 592 oC for 30 wt% ZnO nanocomposites.
Sample
code
% ZnO in the PAEK
matrix
By wt. By vol.
NC-0 0 0
NC-5 5 1.19
NC-10 10 2.49
NC-20 20 5.44
NC-30 30 8.97