TELKOM
NIKA
, Vol.12, No
.4, Dece
mbe
r
2014, pp. 76
3~7
7
2
ISSN: 1693-6
930,
accredited
A
by DIKTI, De
cree No: 58/DIK
T
I/Kep/2013
DOI
:
10.12928/TELKOMNIKA.v12i4.115
763
Re
cei
v
ed
Jul
y
17, 201
4; Revi
sed O
c
tob
e
r 4, 2014; A
c
cepted O
c
to
ber 27, 20
14
Improving the Dielectric Properties of High Density
Polyethylene by Incorporating Clay-Nanofiller
Ossama E. Gouda*
1
, So
hair F. Mahmoud
2
, Ahm
e
d A. El-Gen
dy
3
, Ahmed S. Haiba
4
1
Cairo Un
ivers
i
t
y
, F
a
cult
y
of E
ngi
neer
in
g, Electrical D
epart
m
ent
Giza, Eg
ypt, Ph./F
ax:+
202-
35
702
19
3/357
23
486
2,4
National Inst
itute of Standar
ds (NIS
), High
Voltag
e Metrol
og
y La
b.
T
e
rsa street, El
-Haram, Giza, Eg
ypt, Ph./F
ax:+
202-33
88
976
0/338
67
451
3
Nationa
l Institute of Standar
ds (NIS), N
ano
techno
lo
g
y
and
Nanom
etrolo
g
y
L
ab.
T
e
rsa street, El
-Haram, Giza, Eg
ypt, Ph./F
ax:+
202-33
88
976
0/338
67
451
*Corres
p
o
ndi
n
g
Author, e-ma
il: prof_oss
a
ma
11@
ya
ho
o.co
m
A
b
st
r
a
ct
Polymer
nanocomposites have been used for
vari
ous important industr
ial applications. T
he
preparation of high density polye
thylene composed w
i
th Na-montmorillonite nanofiller using
melt
compounding method
for different
concentrations of
clay-nanofiller of
0%, 2%,
6%, 10%,
and 15% has
been successfully done. T
he
morphology
of the
obtained samples w
a
s
optimiz
ed and characteriz
ed
by
scanning electron microscope
show
ing
the formation
of the polymer
nanoc
omposites. The t
hermal stability
and dielectric properties w
e
re
measured for the pr
epared
samples. T
hermal gravimetric analysis
results
show
that thermal
stabilit
y in
polymer nanocomposites
is more
t
han that
in the
base polymer.
It has
been
show
n
that the polymer nanoc
omposites exhibit some very differ
ent dielectric characteristics w
hen
compared to the
base polymer.
T
he dielectric
br
eakdow
n strength
is enhanced
by
the
addition of
clay-
nanofiller. The
dielec
tric constant
(
ε
r
) and dissipation
factor (T
an
δ
)
have been studied
in the frequency
range 200 Hz
to 2 MHz
at room temperature
indicating that enhancements have been occurred in
ε
r
and
T
an
δ
by the addition
of clay-nanofiller
in
the
polymer material w
hen
compared w
i
th
the
pure
material.
Ke
y
w
ords
:
p
o
l
y
mer
n
anoc
o
m
posites, hi
gh d
ensity poly
e
thy
l
en
e,
di
el
ectric
break
dow
n, d
i
electric
consta
nt,
dissipation factor.
1. Introduc
tion
Polymers pl
a
y
an importa
nt role for m
any
appli
c
ati
ons d
ue to their uni
que p
r
ope
rtie
s
whi
c
h
can
be
cla
s
sified a
s
heat
sen
s
itive, flexible
, el
ectri
c
ally in
su
lating, amo
r
p
hou
s, or sem
i
-
cry
s
talline m
a
terial
s. For that reason, polym
ers are
the most
comm
only used
di
electrics
because of t
heir
reliabilit
y, availability, ease of fabri
c
ations
, and l
o
w
cost. The selection of
the
prop
er diel
ectric polyme
r
for a desi
r
e
d
appli
c
ation d
epen
ds on th
e requi
rem
e
n
t
s and ope
rat
i
ng
con
d
ition
s
of the applie
d system [1]. The elect
r
ic
al propertie
s
of p
o
lymers ca
n
be improved
by
the additio
n
of inorg
ani
c
nano
-fillers t
o
the polym
ers fo
rmin
g
new m
a
teri
al
s called
polymer
nano
com
p
o
s
i
t
es (P
NC). Polymer na
no
compo
s
ites
are com
p
o
s
ite material
s hav
ing seve
ral
wt%
of inorg
ani
c particl
es
of n
anomete
r
di
mensi
o
n
s
ho
mogen
eou
sly
dispe
r
sed in
to their poly
m
er
matrix. PNC
with better
di
electri
c
a
nd
electri
c
al i
n
sulation p
r
op
e
r
ties a
r
e
slo
w
ly eme
r
ging
as
excelle
nt functional mate
ri
als for diel
ectrics
and ele
c
tri
c
al insulat
i
on appli
c
atio
n and the term
“nan
odiel
ectri
c
s” for su
ch
material
s is i
n
crea
singly b
e
comi
ng po
p
u
lar. Althoug
h the technol
ogy
of addition of fillers to poly
m
ers to enha
nce a pa
rt
icul
ar diele
c
tri
c
p
r
ope
rty has b
een in existe
nce
for several decades [2]-[4], the e
ffect
of filler size
on the dielec
tric of the pol
ymer com
p
osites
has
not be
en
unde
rstood f
u
lly. It is with
the adv
ent of
nanote
c
h
nol
ogy leadi
ng t
o
the availa
bi
lity
and
comm
ercializatio
n of n
anop
articl
es that pol
yme
r
nano
com
p
o
s
i
t
e tech
nology
starte
d to
ga
in
momentum.
Polymer nan
ocom
po
sites
have bee
n f
ound to exhibi
t enhan
ced p
h
ysical, thermal,
mech
ani
cal,
and
diele
c
tri
c
pro
p
e
r
ties
when
com
p
a
r
e
d
to the
tradi
tional polym
e
r
mate
rial
s a
nd
that too at low nano-filler
concentrations [1-10%
] [5]-[7]. However it is only recently that the
diele
c
tric p
r
o
pertie
s
of su
ch polyme
r
n
ano
comp
osit
es we
re loo
k
ed into and limited, rese
a
r
ch
results demo
n
strate
very encouragin
g
diele
c
tric
pr
operties
for thes
e materi
als. Ir
r
e
s
p
ec
tive of
the type of b
a
se
polyme
r
material
(the
rmopla
s
tic or thermo
set), significa
nt
enh
ancement
s
in
several phy
sical properties, like
therm
a
l conductivity (w
ith conducting fillers)
or di
electri
c
prop
ertie
s
like resi
stivity,
permittivity, d
i
ssi
pation
fa
ctor, dielect
r
ic stren
g
th, tracki
ng an
d pa
rtial
Evaluation Warning : The document was created with Spire.PDF for Python.
ISSN: 16
93-6
930
TELKOM
NIKA
Vol. 12, No. 4, Dece
mb
er 201
4: 763
– 772
764
discha
rge
re
sista
n
t ch
aracteri
stics
(with insul
a
ting
fillers)
were
observed when comp
are
d
to
simila
r prop
erties in tra
d
itional n
eat
polymer
s [
8
]-[10]. The
s
e ob
servatio
ns
we
re ma
inly
attributed to
the uniqu
e p
r
ope
rtie
s of nano
parti
cle
s
and the larg
e interfa
c
ial
area i
n
poly
m
er
nano
com
p
o
s
i
t
es [11]-[13].
The
p
r
esent
work
f
o
cu
se
s
o
n
th
e
diele
c
tri
c
p
r
ope
rtie
s
of
PE
nano
com
posite
s
.
Polyethylene
is on
e of the
thermo
pla
s
tic polyolefi
n
which i
s
traditi
onally on
e of
the mo
st wi
d
e
ly
use
d
polyme
r
cla
sse
s
with
appli
c
ation
s
i
n
stru
ctu
r
al, textile, and pa
ckagin
g
indu
strie
s
, and th
eir
nano
com
p
o
s
i
t
es h
a
ve fou
nd m
u
ltiple
a
pplication
s
fo
r the
same
use
s
. T
h
is p
aper
sho
w
s t
h
e
prep
aration
and charact
e
rization of
high den
sity polyethylene compo
s
ed
with Na-
montmorill
oni
te clay-n
anof
iller (HDPE/clay) with di
fferent con
c
en
trations of
cl
ay-nan
ofiller as
0%, 2%, 6%, 10% and 15%. Then the diele
c
tri
c
pr
ope
rties,
su
ch as di
el
ectri
c
co
nsta
nt,
dissipatio
n factor, diele
c
tri
c
bre
a
kdo
w
n,
and insu
l
a
tio
n
resi
stan
ce,
of the prepa
red sam
p
le
s will
be discu
s
sed
and compa
r
e
d
to the base
polymer mate
rial.
2. Experimental Details
2.1. Materials
HDPE
with
melt
flo
w
rate
of
7.5
g/10min
and
den
sity
of
96
0
kg/m
3
is
c
h
o
s
en
as
th
e
ba
s
e
polymer mat
e
rial for the
curre
n
t study
. It was
man
u
factured by the Internatio
nal Com
pany
for
Manufa
c
turi
n
g
Plastic P
r
o
duct
s
. Sodiu
m
montmo
rillonite clay K1
0 (MMT
) wa
s a
c
qui
red from
fluka Chemi
k
a
Com
pany.
Hexade
cyl
Trimethyl A
mmonium B
r
om
ide, modif
i
er o
r
su
rfa
c
tan
t
material, was obtained fro
m
Merck KGa
A
, Darm
stadt, Germa
n
y.
2.2. Modifica
tion
of Cla
y
The
p
r
epa
ratio
n
of
polymer/
c
lay
nano
com
p
o
s
ites
with
g
o
od
di
spe
r
si
o
n
of
clay
lay
e
rs
within the p
o
l
y
mer matrix i
s
not po
ssibl
e
by
physi
cal
mixing of po
lymer and
cla
y
particle
s
. It is
not ea
sy to
dispe
r
se n
anol
ayers in
mo
st polyme
r
s du
e to the
high
face
to fa
ce
st
acking
of lay
e
rs
in aggl
ome
r
a
t
ed tactoi
ds
and thei
r int
r
i
n
si
c hyd
r
op
hi
lisity whi
c
h
make
them i
n
com
patible
with
hydrop
hobi
c
polymers. Th
e intrin
sic i
n
compatibility
o
f
hydrophili
c
clay layers
with hydrop
ho
bic
polymer
chai
ns p
r
event
s the dispe
r
sio
n
of clay
nanol
ayers
within
polymer m
a
tri
x
and ca
uses to
the weak interfacial
interactions.
Modific
a
tion
of clay
layers with
hydro
pho
bic agent
s
i
s
necessa
ry in orde
r to ren
d
e
r the clay la
yers mo
re
co
mpatible with
polymer ch
ai
ns, and result in
a larg
er inte
rlayer spa
c
ing
.
In addition, impr
oving t
he strength
of t
he interfa
c
e bet
wee
n
the
inorg
ani
c a
n
d
the
polym
er m
a
trix. So, Na
-MMT
clay i
s
mo
dified
with the
com
patibli
ze
r of
Hexad
e
cyl Tri
m
ethyl Ammonium Bromi
d
e [14].
100g
of
clay
wa
s
d
i
spe
r
sed
in
to
1000 ml of methanol
sol
v
ent and pla
c
ed o
n
hot pl
ate
with ma
gneti
c
sti
rre
r to
allow
co
ntinu
ous
stir
ring
for 2
hou
rs.
On the
othe
r ha
nd, 10
0
g
of
hexade
cyl tri
m
ethyl ammo
nium bromide
was
diss
olve
d in 500 ml of
methanol. T
hen the
soluti
on
wa
s add
ed to
clay dispersi
on. T
he
stirri
ng co
ntinue
d
for 72 ho
urs.
After that, th
e modified
cl
ay
wa
s filtere
d
a
nd colle
cted.
Finally
the filtrate
wa
s d
r
ie
d in a va
cu
u
m
oven at
70
°C fo
r 6
hou
rs
[15].
2.3.
Prepara
t
ion
of HDPE/Cla
y
Composites
The
concentratio
n
s
of
mo
difi
ed
clay-n
anofille
r
were a
dde
d
as 0%, 2%,
6%, 10%, a
n
d
15% into
the
ba
se
polym
er m
a
teri
al.
HDPE/cl
ay
Nano co
mpo
s
i
t
es we
re pre
pare
d
by
me
lt
c
o
mpounding method
(mas
ter batch
method)
us
ing twin
s
c
rew extruder (TSE) at z
ones
temperature
163°
C 1
67°
C, and 16
7°
C, for zone
1,
zone 2, a
nd
zone 3
re
spe
c
tively. The scre
w
spe
ed
wa
s
maintaine
d
3
0
rpm. After extru
s
ion, t
he d
r
ied
p
e
llets of
nan
ocompo
sites
were
preh
eated u
s
i
ng Morg
an Press Inje
ction
unit at 160 °C for 30 min and inje
cted to prod
uce test
sampl
e
s
with
dimen
s
ion
s
7.5 cm *
7
.5
cm *0.2
5 cm
for diele
c
tri
c
mea
s
u
r
em
ents [15]. Th
e
prep
ared
sa
mples are
ref
e
rred to i
n
thi
s
p
ape
r a
s
HDPE 0% (pu
r
e mate
rial),
HDPE 2%, HDPE
6%, HDPE 10%, and HDP
E 15%.
Evaluation Warning : The document was created with Spire.PDF for Python.
TELKOM
NIKA
ISSN:
1693-6
930
Im
proving the Dielectric Proper
ties of Hi
gh Densit
y Polyethy
lene by .... (Ossam
a
E. Gouda)
765
2.4.
Char
acteriza
t
ion of HDPE
/Cla
y
The
p
r
epa
re
d
sam
p
les
we
re
ch
ara
c
teri
ze
d
b
y
the
scanni
n
g
ele
c
tron
mi
cro
s
cop
e
(SE
M
).
SEM is a type of elect
r
on
microsco
pe t
hat pro
d
u
c
e
s
image
s of a
sampl
e
by scannin
g
it with
a
focu
sed b
e
a
m
of electron
s. The ele
c
trons inte
ra
ct with atom
s in
the sampl
e
, prod
uci
ng variou
s
sign
als that
ca
n b
e
d
e
t
ected
and
that cont
ain
informatio
n about
th
e sample'
s
su
rface
topography a
nd com
p
o
s
ition. The sca
n
n
ing ele
c
tr
o
n
micro
s
cop
e
image
s we
re
carried o
u
t by
usin
g SEM,
model Qu
ant
a 250 FEG (Field Emissi
on Gun
)
attache
d
with EDX unit (Ene
rgy
Dispersive X-ray Analyse
s
), with accele
rating
voltage
30 kV, mag
n
i
f
ication 14x u
p
to 1000
000
x,
and a re
sol
u
tion of 1nm.
Thermal
stability
is
measured
by using
thermo gravi
m
et
ric
analy
s
is (TGA). TGA
experim
ents
were don
e by a shimad
zu
TA-50 the
r
m
a
l analyzer u
s
ing
scanni
n
g
rate of 5 °C/min
unde
r N
2
with
20 ml/min flow rate, from room tempe
r
a
t
ure to 600 °
C
.
2.5. Dielectric
Propertie
s
Dielectric
bre
a
kdo
w
n
refe
rs
to
a
rapi
d
red
u
ction
in
th
e
re
si
stan
ce
of
an
ele
c
tri
c
al
insul
a
tor
wh
en the volta
ge appli
ed
across it
excee
d
s the
b
r
ea
kdo
w
n vo
ltage. Diele
c
tric
brea
kd
own measurement
s we
re pe
rf
orme
d usi
n
g
AC Diele
c
tric Te
st Set, Figure 1
1
. The
sampl
e
s we
re sa
nd
wiched
betwe
en two
elect
r
od
es
a
nd teste
d
at
room temp
era
t
ure u
nde
r an
ac
voltage ra
mp
of 750 V/Sec. Th
e a
c
voltage was
increa
sed
wit
h
a rate of
750 V/Sec
u
n
til
brea
kd
own o
c
curred.
Dielectric
c
o
ns
tant
is
c
a
lled
rela
tive permittivity which i
s
a
para
m
eter th
at indicates th
e
relative cha
r
ge storage
capability
of di
electri
c
s
in
th
e p
r
e
s
en
ce
o
f
an el
ect
r
ic field. The
u
s
e
d
instru
ment i
s
an Agile
nt
E4980A L
CR meter
with
diele
c
tric sa
mple h
o
lde
r
, Figure 1
0
. The
equivalent pa
rallel capa
cit
ance (C
p
) is measured directly by the
LCR meter, then the diele
c
tri
c
con
s
tant is
ca
lculate
d
as
sh
own
below in the results
section.
Dissi
p
a
tion
fa
ctor
i
s
calle
d
lo
ss
tangent
or
T
an
δ
. It repre
s
ent
s the
en
ergy lo
ss in
the
diele
c
trics
an
d it is p
r
eferred to
be
sm
a
ller fo
r
in
sul
a
tion mate
rial
s.
It wa
s m
e
a
s
ured
di
re
ctly by
an Agile
nt E4
980A L
C
R m
e
ter
with diel
ectri
c
sampl
e
holde
r in
the
frequ
en
cy ra
nge 2
00
Hz to 2
MHz at room
temperature.
A
l
so,
insul
a
t
i
on re
si
st
an
ce w
a
s m
eas
ure
d
dir
e
ctly by LCR meter at the s
a
me c
o
nditions
.
3. Results a
nd Discu
ssi
on
3.1.
Scanning Electro
n Micro
scop
y
(SEM)
The morp
holo
g
y of the SEM image
s for
HDPE with 2%
clay, 6% cla
y
, 10% clay, and
15% clay co
mposite
s
is
shown in Figu
res 1
-
4 re
spe
c
tively. Each sampl
e
ha
s two imag
es
with
different m
a
gnifications. Al
l SEM
imag
e
s
fo
r all
sam
p
les reve
aled
that, clay
was
disperse
d
in
polymer
matri
x
very well
and there
wasn’t any ac
cumulation of
cl
ay-nanofille
r i
n
it. An important
observation i
s
that the thickne
s
s
of clay
content is
still in nano-si
ze rang
e. This means th
at the
sampl
e
s
we
re su
ccessfull
y
prepa
red.
Figure 1. SEM image
s for
HDPE 2% sa
mple at (20
0
x & 40000x) m
agnification
s
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766
Figure 2. SEM image
s for
HDPE 6% sa
mple at (20
0
x & 40000x) m
agnification
s
Figure 3. SEM image
s for
HDPE 10% sample at (2
00
x & 40000x) magnification
s
Figure 4. SEM image
s for
HDPE 15% sample at (2
00
x & 40000x) magnification
s
3.2. Thermal
An
a
l
y
s
is
The
therm
a
l
stabili
ty
of
the
pr
e
pare
d
sa
mpl
e
s was m
easured u
s
in
g thermo
-g
ravim
e
tric
analyzer (TG
A
). In this techniqu
e, the weight loss
of the materi
al d
ue to the formation of volatile
comp
oun
ds u
nder d
e
g
r
ad
a
t
ion becau
se
of the
heating
and tempe
r
a
t
ure ri
sing i
s
monitored.
The data available
from TGA is t
abulate
d
in T
able 1 a
nd g
r
aphe
d in Fig
u
re 5 in
clu
d
in
g
T
10%
(onset t
e
mpe
r
ature),
the tempe
r
at
ure
at wh
ich
10% de
grada
tion from
the
sam
p
le
occu
rs,
T
50%
, the temperature
at
whi
c
h
50%
deg
rad
a
tion
occu
rs, T
max
, the temperature at
wh
ich
maximum de
grad
ation o
c
curs, an
d re
sid
ual loss at 60
0 °C.
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proving the Dielectric Proper
ties of Hi
gh Densit
y Polyethy
lene by .... (Ossam
a
E. Gouda)
767
Table 1. TGA
result
s for HDPE and HDPE/clay comp
osite
s
Samples
T
10
%
(°C
)
T
50
%
(°C
)
T
max
(°C
)
Resid
u
al Weig
h
t
Los
s (
m
g)
at 600 °
C
HDPE
0%
403.6
451.4
478.3
0.32
HDPE
2%
403.5
451.6
479.3
0.42
HDPE
6%
396.7
459.0
481.2
1.24
HDPE
10%
399.1
463.1
484.2
1.77
HDPE
15%
405.3
464.8
485.1
4.34
Ac
c
o
rding
to
TGA
results
as
shown in figure 5, the inco
rpo
r
ation of
MMT to HDPE
improve
d
the
thermal
sta
b
ility at higher de
gra
datio
n tempe
r
ature ran
g
e
s
co
mpared to p
u
re
HDPE. T
he t
e
mpe
r
ature o
f
the 10%
de
grad
ation
of
HDPE
2%, HDPE 6%
and
HDPE 10%
ha
s
been
shifted
to lo
we
r t
e
mpe
r
atures rel
a
tive to
HDPE 0%,
whil
e the
10% de
grad
ation
temperature
of HDPE 15
% shifted to
highe
r te
mp
e
r
atures comp
ared
to
HDP
E 0%. The
5
0
%
and maximu
m degradatio
n temperatures have
bee
n
shi
fted to hig
her temp
erature
s
compa
r
e
d
to
HDPE 0%. This me
an
s that, thermal stabilit
y has b
een o
c
curred
with
increasi
ng
the
con
c
e
n
tration
of MMT composed to HDPE. The
re
sidu
al weig
ht of the samples at 600
°
C
increa
sed
with increa
sing t
he co
ncentrat
i
on of clay co
mposed to
HDPE. Thus, therm
a
l stabili
ty
of HDPE/clay
has be
en im
proved
com
p
ared to pu
re
HDPE.
Figure 5. TG
A curve
s
for
HDPE an
d HDPE/clay co
mposite
s
3.3. Dielectric
Propertie
s
3.3.1.
Dielectric Br
eakdo
w
n
Str
e
ngth
The dielectri
c
b
r
ea
kdo
w
n
stren
g
t
h of the com
posite
s
is a
n
a
lyzed u
s
in
g an AC diele
c
t
r
ic
test set at ro
om temperature. The test
wa
s
rep
eated
5 times for each
sampl
e
and the avera
g
e
value wa
s re
corde
d
and pl
o
tted as sh
own in Figure 6.
0
5
10
15
20
25
0
100
200
300
400
500
600
700
HDPE
0%
HDPE
2%
HDPE
6%
HDPE
10%
HDPE
15%
Temperature
(
⁰
C)
Weigh
t
Lo
ss
(mg)
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Figure 6. Diel
ectri
c
brea
kd
own
stren
g
th
measurement
for HDPE/cl
a
y
compo
s
ites
Figure
6
shows
the
behavior
of
the dielectric
strength fo
r HDPE/clay composites.
Results show that the dielectric breakdown volt
age increases with increasing the
concentrations
of clay-nanofiller to HDPE when compared to the
pure material having the same dimensions
until reaching to an optimum value (36.1 kV) at
HDPE 6% then, the breakdown voltage starts to
decrease at 10%,
and 15% clay-nanofillers.
Alt
hough the breakdown
voltage decreases at
10%
clay-nanofiller, it’s value
still larger than
the va
lue of
pure material. It
is observed that
the
breakdown voltage value of the sample HDPE 15%
is lower than that of pure material. As
a
result, the dielectric breakdown
strength has
been improved
at all concentrations of
clay-
nanofiller except 15% clay
conc
entration when compared to
the unfilled material. The
optimum
enhancement occurred at HDPE 6%.
3.3.2.
Dielectric Co
nsta
nt (
ε
r
)
Measured
qua
ntity
wa
s the eq
u
i
valent parall
e
l ca
pa
citance (C
p
) of the
sampl
e
s i
n
the
freque
ncy ra
nge 200 Hz
t
o
2
M
H
z,
the
n
the diele
c
tri
c
con
s
tant (
ε
r
) is calculate
d
by the
follo
wing
equatio
ns [16
]
and plotted as sho
w
n in
Figure 7.
Cᴘ
₀ᵣ
(1)
εᵣ
C
ᴘ
₀
(2)
Whe
r
e:
ε₀
= 8.854*1
0
-12
F/m is the p
e
rmittivity of free sp
ac
e, (A) i
s
the a
r
ea
of electrode
s, a
n
d
(t) is the thickness of the sample
s.
Figure 7 sh
ows the variatio
n of
the diele
c
tric con
s
tant
(
ε
r
) with fre
quen
cy at ro
om
temperature
for all
sample
s. Ob
se
rved
differen
c
e
s
were fo
und
in
diele
c
tric con
s
tant b
e
twee
n
pure
HDPE a
nd HDPE co
mposite
s
with
different con
c
entration
s of clay-na
nofille
r. It is seen that,
ε
r
decre
ases with
in
cre
a
s
ing
fre
que
n
c
y for all
sa
mples.
An i
m
porta
nt ob
servatio
n i
s
that
diele
c
tric
co
n
s
tant de
crea
se
s co
nsi
d
e
r
ably wi
th the
addition of
clay-n
anofille
r up to 6% filler
con
c
e
n
tration
,
and then it increa
se
s at 10%
and 15
% filler con
c
entration
s. T
he value of
ε
r
at
HDPE
10% i
s
still lower than that of
pure HDPE
and
its value
at HDPE 15%, i
s
higher than t
he
pure m
a
terial
. The increa
sing of
ε
r
at 1
0
% and 15%
filler con
c
en
trations m
a
y be due to th
e
31.
3
33.
5
36.
1
34
30.
1
20
25
30
35
40
HDPE
0%
HDPE
2%
HDPE
6%
HDPE
10%
HDPE
15%
Voltage
(kV
)
Dielectr
ic
Breakdown
Voltage
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ISSN:
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Im
proving the Dielectric Proper
ties of Hi
gh Densit
y Polyethy
lene by .... (Ossam
a
E. Gouda)
769
effec
t
of
ε
r
of
comp
osite
s
(i
nclu
sio
n
s
+ matrix) on th
e
re
sultant pe
rmittivity [17],[18]. This me
an
s
that an enha
n
c
eme
n
t occu
rred in diel
ect
r
ic co
ns
ta
nt at 2%, 6%, and 10% filler co
nce
n
tration
s
.
Figure 7. Fre
quen
cy dep
e
nden
ce of die
l
ec
tri
c
co
nsta
nt at room temperature
3.3.3.
Dissipa
tion Factor (Ta
n
δ
)
Figure
8
s
h
ows
the
variation of
the dissi
pati
on facto
r
(Ta
n
δ
) with fre
quen
cy at ro
om
temperature f
o
r all
sampl
e
s. As sho
w
n i
n
the figure, Tan
δ
de
crea
se
s with in
cre
a
sin
g
freq
uen
cy
for all sa
mpl
e
s. Also a
n
importa
nt observation i
s
that Tan
δ
de
cre
a
s
e
s
wit
h
incr
ea
sing t
h
e
concentrations of
clay-nanofiller in
corporated i
n
poly
m
eri
c
material
up to 6% fill
er
concentrati
on,
then it fu
rth
e
r i
n
crea
se
s at 1
0
% an
d 15%
f
iller co
ncentratio
n
s. T
h
is ma
y be
due
to
the
increasing of
conductivity accord
i
n
g to increasi
ng of
nano-filler concentration
[17],[18]. It is seen
that the values of Tan
δ
for HDPE 10% sampl
e
are le
ss tha
n
that of pure mate
rial. On the othe
r
hand, the values of Tan
δ
for 15% filler con
c
e
n
trati
ons a
r
e
high
er than that of pure mate
rial.
This means that clay-n
anofiller improves the dissipation fa
ctor for HDPE polym
eric m
a
terial.
Figure 8. Fre
quen
cy dep
e
nden
ce of di
ss
ipatio
n facto
r
at room tem
peratu
r
e
3.
80
4.
00
4.
20
4.
40
4.
60
2.
2
2
.
7
3.
2
3
.
7
4.
2
4
.
7
5.
2
5
.
7
6.
2
HDPE
0%
HDPE
2%
HDPE
6%
HDPE
10%
HDPE
15%
Dielectric Constant
Log (Frequency)
0.
000
0.
010
0.
020
0.
030
0.
040
0.
050
0.
060
0.
070
0.
080
2.
2
2
.
7
3.
2
3
.
7
4.
2
4
.
7
5.
2
5
.
7
6.
2
HDPE
0%
HDPE
2%
HDPE
6%
HDPE
10%
HDPE
15%
Tan
(
δ
)
Lo
g
(Frequenc
y)
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770
3.3.4.
Insulation Resista
n
ce (R)
Figure
9
sho
w
s
the
vari
ation
of
the in
sulat
i
on resi
stan
ce (R)
with freque
ncy at
room
temperature
for all sa
mpl
e
s. Ma
rke
d
differen
c
e
s
were foun
d in the insula
tion re
sista
n
c
e
betwe
en p
u
re
HDPE a
nd
HDPE
comp
o
s
ites
with diff
erent
con
c
e
n
tration
s
of cl
a
y
-nanofille
r. It is
see
n
that, the insul
a
tion
decrea
s
e
s
wi
th increa
sing
freque
ncy for all sample
s. An import
ant
observation i
s
that the i
n
sulatio
n
in
cre
a
se
s
with
th
e additio
n
of
clay-nanofill
er u
p
to 6%
filler
con
c
e
n
tration
,
and then it
decrea
s
e
s
at
10% and
15
% filler co
ncentration
s. Al
though th
at, the
insul
a
tion resistance value at 10% filler
concentration
is
still high
er than that of
pure
HDPE. On
the other hand, the insul
a
tion resi
st
ance value
at 15% filler
concentr
ations i
s
lower than that
of
pure
sample.
The d
e
crea
si
ng of the
in
su
lation resi
sta
n
ce
at 10% fil
l
er
con
c
e
n
trat
ion may
be d
u
e
to the increa
sing of cond
uctivity
of composite
s
at
high con
c
ent
ration
s. This mean
s that an
enha
ncement
occurred i
n
the insul
a
tion re
si
stan
ce up to 10
% filler con
c
entration
when
comp
ared to pure m
a
terial.
Figure 9. The
insulatio
n
re
sista
n
ce varia
t
ion wi
th varia
b
le frequ
en
ci
es at ro
om temperature
Figures 1
0
,1
1 sho
w
the
instrum
ents whic
h u
s
e
d
for diele
c
tric an
d bre
a
kd
own
measurement
s re
spe
c
tively.
Figure 10. Agilent E4980A
LCR meter
wi
th dielectri
c
sample hol
der
0
500
1000
1500
2.
2
2
.
7
3.
2
3
.
7
4.
2
4
.
7
5.
2
5
.
7
6.
2
HDPE
0%
HDPE
2%
HDPE
6%
HDPE
10%
HDPE
15%
Resistance
(M
Ω
)
Lo
g
(Frequenc
y)
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ISSN:
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Im
proving the Dielectric Proper
ties of Hi
gh Densit
y Polyethy
lene by .... (Ossam
a
E. Gouda)
771
Figure 11. Di
electri
c
test
set for dielect
r
i
c
bre
a
kdo
w
n
measurement
4. Conclusio
n
HDPE/cl
ay
compo
s
ites a
r
e prep
are
d
by melt compoun
ding me
thod (Ma
s
ter Batch
method
). Mo
rpholo
g
y structure
of
the
prepared
sa
mp
les i
s
i
n
ve
sti
gated
by SEM. SEM ima
ges
sho
w
th
at cl
ay co
ntent i
s
well
dispe
r
se
d in
the
polyme
r
m
a
trix indi
cati
ng
sampl
e
s are
su
ccessfully
prep
ared. Th
ermal
stabilit
y and di
el
ectric p
r
op
ertie
s
a
r
e inve
sti
gated fo
r th
e
prepared samples. T
G
A result
s show t
hat HD
PE nanocomposites have th
erm
a
l stability m
o
re
than unfilled
polymer mate
rial. Diele
c
tri
c
brea
kdo
w
n
strength is im
p
r
oved by
the addition of cl
ay-
nanofille
rs. Dielectri
c
con
s
tant and dissipation fact
o
r
are studie
d
at room temperatu
r
e in the
freque
ncy
ran
ge 20
0 Hz to
2 MHz. The
e
x
perime
n
tal result
s sho
w
that there i
s
a
n
enh
an
ceme
nt
in both
ε
r
an
d Tan
δ
due
to the uniq
u
e
beh
avior of
clay-n
anofill
er
when i
n
co
rpo
r
ated i
n
to
the
polymer ba
se matrix
HDPE. Also in
sulation
re
sist
ance h
a
s be
en im
prove
d
by the
additi
on of
clay-n
anofille
r. From all re
sults, It can b
e
noticed
that
6% filler con
c
entration is t
he optimum clay
conte
n
t for HDPE/clay system.
Referen
ces
[1]
BX
. Du, HJ.
Liu. Effects of
Atmosph
e
ric
Pressure
on
T
r
ackin
g
F
a
il
ur
e of Gamma-r
a
y
Irradi
ate
d
Poly
mer Insula
ting Mater
i
als.
IEEE Transactions o
n
Die
lect
rics and El
ectri
c
al Insul
a
tio
n
. 201
0; 17(2).
[2]
F. Carmona. C
ond
uctin
g
Fille
d Pol
y
mers.
Physica A
. 1989;
157: 46
1-4
69.
[3]
Y. Bai, Z
Y
. Ch
eng, V. B
harti,
HS.
Xu, QM. Z
hang.
Hig
h d
i
electric-co
n
sta
n
t ceramic-
po
w
d
er
po
l
y
m
e
r
compos
ites.
Appli
ed Phys
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. 200
0; 76(2
5
): 380
4-3
806.
[4]
MM. Ueki, M.
Z
anin. Influ
enc
e of add
itives
on t
he d
i
el
ectr
ic strength of
High-
de
nsit
y
P
o
l
y
eth
y
l
e
n
e
.
IEEE Transactions on D
i
el
ectrics and El
ectric
al Insul
a
tio
n
. 1999; 6(6): 8
76-
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mith, EP. Giann
elis. S
y
nt
hesis
an
d C
haracter
i
zatio
n
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ye
re
d
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ate-Ep
o
xy
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o
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osit
es.
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istry of Materials
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19-1
725.
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y
,
M. Okamoto. Pol
y
mer/l
a
yer
ed
silic
ate
na
noc
ompos
ites: a
revie
w
fr
om p
r
epar
ation
t
o
process
i
ng.
Pr
ogress i
n
Poly
mer Sci
enc
e
. 2003; 28: 1
539-
164
1.
[7]
R. Gensler, P.
Groppe
l, V. Mu
hrer
, N. Mu
ller.
Appl
icati
ons
o
f
Nano
partic
l
es
in P
o
l
y
mers f
o
r Electron
ic
and El
ectrical
Engi
neer
in
g.
Particle a
nd Part
icle Syste
m
s C
haracter
i
z
a
tio
n
. 2002; 19: 29
3
-
299.
[8]
T
.
T
anaka. Dielectric N
anoc
ompos
ites
w
i
th
Insulatin
g
Pro
perties.
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s
and El
ectrical I
n
sul
a
tion
. 2
005
; 12(5): 914-9
2
8
.
[9]
Y. Cao, P. C. Ir
w
i
n, K. Youn
s
i
. T
he F
u
ture of Nano
die
l
ectri
cs in the El
ectrical Po
w
e
r In
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u
str
y
.
IEEE
T
r
ansactio
n
s o
n
Diel
e
ctrics a
nd Electric
al In
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