Studying the Effect of CrCl2 Addition on the Electrical Properties of
Polystyrene
Raheem Gaayid1 , Angham.G.Hadi2 ,Farhan Lafta3 , Ahmed. Hashim4
1,2,4Babylon University, Iraq
3Ministry of Science and Technology, Iraq
3E-Mail: engfarhan71@gmail.com
4E-Mail: ahmed_taay@yahoo.com
Abstract
In this work, samples of pure polystyrene and polystyrene (PS) doped with
(CrCl2) were prepared using casting method .The effect of addition of chromium
chloride concentration on electrical properties of polystyrene have been studied, also
the effect of the concentration of chromium chloride and temperature on the electrical
conductivity was studied, then the variation in activation energy of D.C electrical
conductivity have been investagated. The results show that the electrical resistance
was decreased with increasing temperature and the activation energy was decreased
with increasing the concentration of chromium chloride, also the electrical
conductivity was increased with increasing the concentration of chromium chloride.
Key words: polymer, PS, chromium chloride, electrical properties, conductivity.
1. Introduction
A polymer of a particular group is characterized by the molecular weight of the
monomer unit. Polystyrene (PS) is amorphous polymer with bulky side groups.
General purposes PS is hard, rigid, and transparent at room temperature and glass like
thermoplastic material which can be soften and distort under heat. It is soluble in
aromatic hydrocarbon solvents, cyclohexane and chlorinated hydrocarbons [1].
Many researchers succeeded to prepare PS as films deposited on various
substrates such as glass or silicon wafer [2,3], this interest was by the technological
importance of film stability (e.g Toys and novelties, rigid packaging, refrigerator
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trays, boxes, cosmetic packs and costume jewelers, lighting diffusers, audio cassette
and CD cases ).
Polymer capped inorganic nanoparticle composites have attracted much attention
recently due to their enhanced optical and electronic properties. For example, CdSe–
polymer composites can be used to make blue light emitters [4, 5]. The altering and
enhancement of the polymer’s properties can occur through doping with various
nano-fillers such as metals, semiconductors, organic and inorganic particles and
fibres, as well as carbon structures and ceramics [6-9].
The present study will help in understanding the effect of different concentrations of
chromium salt on the D.C conductivity of polystyrene.
2. Experimental Part
Polystyrene solution was prepared by dissolving it in cloroform by using
magnetic stirrer in mixing process to get homogeneous solution. The wieght
percentages of CrCl2 are (4, 8 and 12 )wt .% were added and mixed for 10 minute to
get more homogenous solution.
Casting Method was applied by using Petri dish that leaved to dry at room
temperature for three days. The dried film was then removed easily by using tweezers
clamp.
The resistivity was measured over range of temperature from (30 to 80)oC using
Keithly electrometer type (616C) .The volume electrical conductivity ? ? defined
by :
Where :
A = guard electrode effective area.
V/I=R = volume resistance (Ohm) .
L = average thickness of sample (cm) .
1 .......... .........( 1)
AI
LV
v
= = ? ? ?
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In this model the electrodes have circular area A= D2?/4 where D= 0.5 cm2 .
The activation energy was calculated using equation :
? = ?o exp(-Ea/kBT)…………………..(2)
? = electrical conductivity at T temperature
?0 = electrical conductivity at absolute zero of temperature
KB = Boltzmann constant
Ea = Activation Energy