Third Day Poster Session, 17 June 2010 - NanoTR-VI

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Poster Session, Thursday, June 17
Theme F686 - N1123
Electrical Behaviours of Flame Retardant Huntite and Hydromagnesite Reinforced Polymer
Composites for Cable Applications
1,2
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UHüsnügül Ylmaz AtayUP
P*, Erdal ÇelikP
PDepartment of Metallurgical and Materials Engineering, Dokuz Eylul University, 35160 Izmir, Turkey
PCenter for Fabrication and Applications of Electronic Materials, Dokuz Eylul University, 35160 Izmir, Turkey
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Abstract - As huntite and hydromagnesite mineral undergoes an endothermic decomposition with water and carbon dioxide release, it has
been studied as flame retardant filler for polymers in potential electrical applications. In this study, the electrical properties of flame retardant
huntite and hydromagnesite mineral reinforced polymeric composites were investigated. Phase and microstructural analysis of huntite and
hydromagnesite powders were undertaken using XRD and SEM-EDS preceeding the fabrication of the composite materials. The minerals
with different particle size and content were subsequently added to ethylene vinyl acetate copolymer to produce composite materials. After
the fabrication of composites, their electrical properties such as conductivity, dielectric constant, specific resistance, impedance, capacitance
and dissipation factor were investigated as a function of particle size and loading level. It was concluded that conductivity increased with
decreasing particle size to nanoscale.
Due to their low weight and ease of processing, the use
of polymers is arised by their remarkable combination of
properties in our daily life. Even though to be used in so
many areas and show great facilities, polymers are also
known for their relatively high flammability. Beside, most
of them are accompanied by corrosive or toxic gases and
smoke which are produced while the combustion is
continuing [1]. So that, it is rising as an important issue to
extent polymers’ usage for obtaining their fire resisting
property for the applications [2]. Hence some ancillary
materials are used to make polimers fire resistant. They are
added into the compound whose application properties
became closely related to the physical properties of the
additive itself. Huntite/hydromagnesite is a halojen free
inorganic mineral that can be used as a flame retardant
additive to the flammable polymeric materials. Its
effectiveness comes from the fact that it decomposes
endothermically and consumes a large amount of heat,
while also liberating water, which can dilute any volatiles
and thus decrease the possibility of fire (Equations 1 and
2) [3]. Decomposition begins at somewhat higher
temperature, near 400°C, and consumes 1244 J/g [4].
MgR4R(COR3R)R3R(OH)R2R.3HR2RO 4MgO + 3COR2R+4HR2RO (1)
MgR3RCa(COR3R)R4R 3MgO + CaO + 4COR2R (2)
In the present work, a series of composites were
prepared using an ethlylene vinyl acetate copolymer
matrix and different concentrations of
huntite/hydromagnesite mineral to ethylene vinyl acetate
copolymer to evaluate the electrical properties. In this
sense, properties of complex conductivity, impedance,
capacitance, dissipatation factor, dielectric constant and
specific resistance measurements were performed to
huntite hydromagnesite reinforced plastic
compositesamples.
. Only conductivity test results is shown here (Figure 1).
The result shows that decreasing the size to nano scale
makes the polymer composite more conductive. On the
other hand, in spite of the fact that it seems to be changing
the conductivity related with the loading level, it can be
expressed that increasing filler amaount increased the
polymer’s conductivity. The increase in conductivity with
the increasing of the filler amount mainly stems from the
establishing of conducting networks in the polymer matrix
[5]. In addition, we have a good aggrement with the
literature [6] that finer particles may support this
mechanism as the ionic conductivity of the polymer
composite increased. In toher words, for both size effect
and the loading level effect tests, it can be seen that
frequency assists helps to increase conductivity of the
composites. The other electrical properties such as
dielectric constant, specific resistance, impedance,
capacitance and dissipation factor were improved with
changing particle size and content.
Complex Conductivity (S/cm)
(a)
0,35
0,30
0,25
0,20
0,15
0,10
0,05
0,00
-0,05
10 μm
1 μm
0.1 μm
0,0 2,0x10 6 4,0x10 6 6,0x10 6 8,0x10 6 1,0x10 7
Frequency (Hz)
Complex Conductivity (S/cm)
0,32
0,30
0,28
0,26
0,24
0,22
0,20
0,18
0,16
0,14
0,12
0,10
0,08
0,06
0,04
0,02
0,00
-0,02
49%
55%
61%
64%
67%
69%
0,0 2,0x10 6 4,0x10 6 6,0x10 6 8,0x10 6 1,0x10 7
(b)
Frequency (Hz)
Figure 1. Conductivity of huntite/hydromagnesite reinforced
plastic composite materials as a function of frequency according
to (a) particle sizes and (b) contents of reinforced powder
The authors would like to acknowledge to Likya Minelco
Madencilik Sti. and Minelco Specialities Limited.
*Corresponding Author: HThgulyilmaz@gmail.comTH
[1] O’Driscoll, Mike. (1994). Industrial Minerals December.
[2] F. Laoutid, L. Bonnaud, M. Alexandre, J.-M. Lopez-Cuesta,
Ph. Dubois (2008). Materials Science and Engineering R
[3] Ahmed Basfar, and H. J. (2009) Journal of Fire Sciences.
[4] Haurie, L., at al. (2006). Polymer Degr. And Stability 91 (5)
989-994.
[5] Guohua Chen at al (2007).Mat. Chem. and Phy. 104 240–243
[6] Zhaoyin Wena at al. (2003) Solid State Ionics 160 141– 148
6th Nanoscience and Nanotechnology Conference, zmir, 2010 715