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: rkgoyal72@yahoo.co.in, 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