Advances in Nanoparticles, 2013, 2, 205-216
http://dx.doi.org/10.4236/anp.2013.23029 Published Online August 2013 (http://www.scirp.org/journal/anp)
Evaluation of Mo rph ologic a l Effect on Thermal and
Mechanical Performance of PS/PMMA/CdS
Nanocomposite Systems
Vishal Mathur1,2,3, Kananbala Sharma3
1Department of Physics, S. S. Jain Subodh P.G. College, Jaipur, India
2Department of Engineering Physics, Kautilya Institute of Technology & Engineering,
Riico Institutional Area Sitapura, Jaipur, India
3Semiconductor and Polymer Science Laboratory, Vigyan Bhawan, University of Rajasthan, Jaipur, India
Email: wishalmathur@gmail.com, wishalmathur@yahoo.co.in
Received March 6, 2013; revised April 6, 2013; accepted April 15, 2013
Copyright © 2013 Vishal Mathur, Kananbala Sharma. This is an open access article distributed under the Creative Commons Attri-
bution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
ABSTRACT
In the present paper an effort has been made to investigate effect of dispersion of CdS nanoparticles on the thermal and
mechanical properties of PS/PMMA blends. Samples have been prepared through dispersion of CdS nanoparticles
(prepared separately) during solution casting blend fabrication processing. These nanocomposites samples are structur-
ally characterized through Wide angle X-ray Scattering (WAXS) and Small Angle X-ray Scattering (SAXS) techniques.
Scanning Electron Microscopy (SEM) analyses of these samples have been carried out in lieu of surface morphological
characterization. The measurements of glass transition temperature and stress-strain analyses have been performed
through Dynamic Mechanical Analyzer (DMA). The thermal conductivity of nanocomposite samples has been determined
using Hot Disk Thermal Constants Analyzer. The study shows that the incorporation of dispersed CdS nanoparticles in
PS/PMMA blend matrix significantly alter their glass transition behaviour, thermal conductivity and tensile properties.
Keywords: Thermal Conductivity; CdS Nanocomposites; Glass Transition Temperature; Tensile Properties
1. Introduction
High performance in polymer blends and composites can
be achieved through the addition of a strong filler com-
ponent into a polymer matrix. In this regard polymer
nanocomposites present a promising alternative of con-
ventional composites. Recently, studies on blends of im-
miscible polymers containing nanoparticles have attracted
the attention of several research groups [1-5]. Chung et
al. [6] made the first quantitative study of phase separa-
tion dynamics in a polymer blend containing mobile 22
nm silica nanoparticles. These studies suggest that under
certain conditions the polymer molecules and the nanopar-
ticles should not be regarded as individual entities within
the blend, but instead as complex aggregates. Numerical
simulations of polymer nanocomposites have shown that
the introduction of hard spheres into a polymer blend has
similar effects to the introduction of new polymer/hard-
wall interfaces [7,8]. Vacatello [9] performed simulations
of polymer systems filled with particles of a size compa-
rable to the polymer chains and found that even in the
absence of specific interactions with the polymer, the
filler particles behaved as highly functional physical cross-
links, reducing the overall mobility of the polymer chains
compared to the unfilled polymer matrix.
Nanoparticles particularly II-VI semiconductors have
attracted wide spread attention, because they are rela-
tively easy to synthesize in the size range required for the
quantum confinement. In accordance with the need, vari-
ous inorganic semiconductors such as CdSe, CdTe, CdS,
and PbS, have been actively investigated and among
these CdS has been known as one of the most promising
photo-sensitive material owing to its unique photochemi-
cal activities and strong visible-light absorption and emis-
sion property [10]. Hence, it has many commercial or
potential applications in light-dependent resistors, solar
cells, or other photo-electronic devices [11-13]. The nano-
composite of CdS can provide the possibility to provide
combinations of functionalities, such as thermally con-
ducting composites with good mechanical properties that
are optically clear. Such properties can result because
C
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V. MATHUR, K. SHARMA
206
CdS nanoparticles, with diameters distinctly below the
Rayleigh scattering limit, still display their solid-state
physical properties when embedded in transparent ma-
trices. Basically CdS nanocomposites are optical com-
posites and most of the studies of these are concerning
optical characterization [14-17]. The different technologi-
cal applications of CdS nanocomposites include biologi-
cal labeling and diagnostics, LED’s, electro-luminescent
devices, photovoltaic devices, lasers and single electrode
transistors. These applications of CdS nanocomposites in
various fields necessitate the proper understanding of
their thermal and mechanical properties because along
with mechanical performance, the system has to entail
heat transition phenomenon almost in all applications.
In view of this, the present work is aimed to establish
concepts to obtain nanocomposites with desired proper-
ties to enhance compatibility of immiscible blends as
well as to understand the mechanical and thermal stabil-
ity of these systems. An extensive study of thermal and
mechanical properties through two major experimental
set up namely Hot Disc Thermal Constant Analyzer (TPS)
and Dynamic Mechanical Analyzer (Tritec 2000 DMA),
respectively have been under taken in detail. In view of
this, above mentioned aspects have been studied using
PS/PMMA blends and their CdS nanocomposites (PS/
PMMA/CdS). PS and PMMA both are well known due
to their various commercial and domestic applications
and stand as primary industrial polymeric materials [18,
19]. The study shows that the incorporation of dispersed
CdS nanoparticles in PS/PMMA blend matrix signifi-
cantly alter their glass transition behaviour, thermal con-
ductivity and tensile properties.
2. Experimental
2.1. Material Preparation
In order to prepare polymeric blended-nanocomposite
samples, firstly CdS nanoparticles have been prepared by
simple chemical method using CdCl2 and H2S gas produced
from thiourea [20]. The samples of PS/PMMA/CdS poly-
meric nanocomposite have been prepared by dispersing
prepared CdS nanoparticles during the preparation of
polymeric blends of different concentrations (0%, 30%,
50%, 70%, and 100%) of PS/PMMA through solution
casting method. In this method the laboratory grade
polymeric material which are to be blend are dissolved
accordingly in the tetrahydrofurane (T.H.F.) solvent. Then
10% chalcogenide CdS nanofiller particles of blending
composition were dispersed in this solution. This solu-
tion was then stirred with the help of magnetic stirrer and
then poured into flat-bottomed petri dishes to form film
with a thickness of ~0.05 mm. The solvent is allowed to
evaporate slowly over a period of 24 hours in dry at-
mosphere. The so obtained film was then peeled off and
dried in vacuum at 50˚C, well below the boiling point of
solvent to avoid bubbling, for 24 hours in order to ensure
the removal of the solvent [21,22].
2.2. Hot Disk Thermal Constants Analyzer
Measurements
Thermal transport properties of PS/PMMA polymeric
blends of thickness about 2 mm have been measured
through the Hot Disk Thermal Constants Analyzer from
room temperature to 120˚C. It is based on transient plane
source (TPS) technique. The TPS technique consists of
an electrically conducting pattern, in the form of a bifilar
spiral, which serves both as the source of heat and as a
temperature sensor. The sensor is sandwiched between
the thin insulating layers of Kapton. The TPS sensor
element is made of 10 μm thick nickel foil with an insu-
lating layer made of 50 μm-thick Kapton, on each side of
the metal pattern. The voltage increase over the sensor is
recorded precisely. The evaluation and measurements of
thermal conductivity and thermal diffusivity were per-
formed in a way mentioned by Gustafsson [23] and com-
puter software supplied in TPS 2500 S.
2.3. Dynamic Mechanical Analyzer (DMA)
Measurements
Dynamic Mechanical Analyzer (TRITEC-2000 DMA) is
a sensitive technique that characterizes the mechanical
response of materials by monitoring property change with
respect to the temperature and frequency of applied si-
nusoidal stress. DMA film samples were cut to be be-
tween 4 - 6 mm in width and 10 mm in length. The av-
erage thickness of each sample is of 100-micrometer
order. After adjusting DMA device in tension mode, the
furnace was sealed off, sample scanned over a tempera-
ture range from room temperature to 140˚C. The sample
was held at that temperature for five minutes. The heat-
ing/ramp rate was 2˚C/min for all temperature scan tests.
Frequency of oscillations was fixed at 1 Hz and strain
amplitude 0.01 mm within the linear visco-elastic region.
The storage modulus E', loss modulus E" and mechanical
loss factor (Tan δ) have been determined during the test
as a function of increasing temperature [22,24].
3. Results and Discussion
3.1. Structural and Surface Morphological
Characterization
The structural characterization of PS/PMMA/CdS nano-
composites is primarily concerned with investigating
whether the dispersed CdS nanoparticles are still within
nano dimension. Two major techniques, namely, wide
angle Xray scattering (WAXS) & small angle X-ray scat-
tering (SAXS), were used to ascertain the nano dimen-
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V. MATHUR, K. SHARMA
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207
sion such. Surface morphological characterizations of the
PS/PMMA/CdS nanocomposites were done through scan-
ning electron microscope (SEM) analysis.
3.1.1. Wide Angl e X-Ra y Sc at teri ng Analysis
WAXS is used to estimate the particle size of prepared
CdS nanoparticles. Figure 1 shows the WAXS pattern of
CdS nanoparticles. The presence of broad peaks confirms
the nano dimension of the prepared nanoparticles. The
average particle size obtained from the Debye Scherrerr
formula [20] is 3 nm. The WAXS patterns for the 50PS/
50PMMA & 50PS/50PMMA/CdS nanocomposite is as
shown in Figure 2.
A broad hallow in the 2θ range of 25˚ - 40˚ is observed
20 30 40 50 60 70 80 90
Intensity
2
Figure 1. WAXS pattern of CdS nanoparticles.
10 15 20 25 30 35 40
(b)
(a)
(a)50PS/50PMMA/C dS
(b )50 P S/50 P MMA/CdS
2
Intensity
Figure 2. WAXS pattern of 50PS/50PMMA & 50PS/50PMMA/CdS.
V. MATHUR, K. SHARMA
208
in the WAXS pattern for 50PS/50PMMA and this is
characteristic of the polymer. The pattern for the 50PS/
50PMMA/CdS nanocomposite exhibits a semi-crystal-
line nature. It can be seen that the random dispersion of
CdS nanoparticles within the 50PS/50PMMA matrix pro-
vides high scattering centers for the incident X-rays giv-
ing intense diffraction peaks. The peak observed in the
pattern of the nanocomposite at 12˚ and 17˚ is thus also a
consequence of this type of scattering of X-rays by the
CdS nanofiller. Similar observations have also been re-
ported by other researchers [25,26]. The pattern for nano-
composite sample does not yield information about the
distribution of nanoparticles within the sample. To as-
certain the above perspectives small angle X-ray scatter-
ing analysis is used.
3.1.2. Small Angle X-Ray Scattering Analysis
SAXS measurements were performed on an X’Pert Pro
MPD system to investigate the size of the CdS-nanopar-
ticles within nanocomposite samples. For the determina-
tion of size, shape, and distribution of particles, data files
obtained from the X’Pert Pro MPD system were matched
with the analysis templates that are provided with the
EasySAXS software. Figures 3(a)-(c) show the scatter-
ing intensity as a function of angle (2θ) for PS, PMMA,
50PS/50PMMA & their CdS nanocomposites respec-
tively.
It is observed that SAXS pattern of CdS embedded
polymer nanocomposites show higher scattering intensity
as compared to without CdS dispersed samples. The nano-
crystals of CdS act as independent scattering centers in
the respective polymer matrices and add to the total scat-
tering intensity in the respective SAXS pattern. SAXS
patterns are used for elucidating the shape and size of
CdS nano-crystals by subtracting the background scat-
tering intensity (without CdS embedded polymeric phase)
from scattering intensity of CdS embedded polymeric/
nanocomposite phases with the help of EasySAXS soft-
ware. SAXS characterization reports of respective nano-
composites suggest that CdS nanofiller particles have
been distributed evenly within the available polymer/
blend matrix and have very little tendency to form agglo-
merates.
Figure 4 shows the particle size distribution curves for
the PS/CdS, PMMA/CdS and 50PS/50PMMA/CdS nano-
composites. The particle size distribution report of this
nanocomposite suggests that the distribution is well ap-
proximated by a Gaussian. The minor oscillations in the
distribution curve around zero toward larger particle radii
may be regarded as insignificant. It is observed that par-
ticle size distribution curve for PS/CdS, & PMMA/CdS
nanocomposites respectively, are approximately centered
at R = 1.3 nm and it means that the most frequent radius
(R) of CdS nanofillers is 1.3 nm and major volume frac-
tion of these CdS nanoparticles is exhibiting radius within
0.6 nm to 2.6 nm. Similarly from curve (c), it is revealed
that R = 3.5 nm is as a most frequent radius of CdS nan-
ofillers along with their particle size variation from R=
6.8 nm to 8.8 nm within the 50PS/50PMMA/CdS nano-
composite matrix. Hence the observed values of average
particle size of CdS nanoparticles in all respective nano-
composite samples lies within nano dimensions (i.e. be-
low 100 nm) and implies that the prepared samples retain
their nanocomposite nature.
3.1.3. Sca n ning Electron Microscopy An a l ys i s
The realistic picture of the degree of CdS nanofillers
dispersion in the nanocomposites can be obtained through
scanning electron microscope analysis. Figure 5 shows
the cross-section SEM micrographs of the PS, PMMA,
70PS/30PMMA, 50PS/50PMMA and 30PS/70PMMA
blends with and without CdS nanoparticles. It can be
seen that the CdS nanoparticles have been uniformly dis-
persed in each polymer base matrix but in dissimilar man-
ner, respectively. In PS/CdS, the concentration of CdS
nanoparticles on the exterior surfaces of PS phase makes
possible large number of contacts and nanophase separa-
tion is observed in this nanocomposite.In PMMA/CdS,
CdS nanoparticles settle down at the void sites of PMMA
matrix and form exfoliated nanocomposite. SEM image
of PS/CdS showed some level of flocculation of CdS
nanoparticles, but of varying sizes. But in the PMMA/
CdS nanocomposite, CdS flocculants were limited and
improvement in compatibility of this system have been
observed.
The immiscible interphases of PS and PMMA exhib-
ited in SEM images of PS/PMMA, are not observed in
SEM images of PS/PMMA/CdS nanocomposites. It sug-
gests that the overall compatibility of the respective blend
system increases. The effect of different morphological
structures of respective nanocomposite is further reflected
in different bulk properties offered by them.
3.2. Glass Transition Temperature
Measurements
The knowledge of glass transition temperature (Tg) is one
of the benchmark used to compare the thermal behavior
of composites. Changes in the Tg as a function of the
filler content have been reported [27-31] for polymer
composites containing a wide variety of fillers and poly-
mers. Results of investigations of PS/PMMA/CdS nano-
composites are shown in Figures 6(a)-(e), respectively.
These figures depict the variation of the Tan δ of the
nanocomposite samples as a function of temperature.
It has also been observed that Tg of CdS embedded
PMMA phase shifts towards the higher temperature side
with the increase of PS content whereas Tg of CdS em-
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012345
10
100
1000
Intensity
2
(a ) P S
(b ) P S/CdS
(a)
(b)
(a)
012345
10
100
1000
Intensity
2
(a ) P MMA
(b ) P MMA/Cd S
(b)
(a)
(b)
012345
10
100
1000
Intensity
2
(a) 50PS/50PMM A
(b) 50PS/50PMM A/CdS
(b )
(a )
(c)
Figure 3. SAXS pattern of CdS nanoc omposites of PS, PMMA & 50PS/50PMMA.
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210
0100 200 300
-0.01
0.00
0.01
0.02
0.03
0.04
0.05
0.06
Radius (Angstrom)
Dv(R)
PS/CdS
PMMA/CdS
PS/PMMA/CdS
Figure 4. Particle size distribution curves for PS/CdS, PMMA/CdS & 50PS/50PMMA/CdS.
bedded PS phase seems to be statistically constant in all
PS/PMMA/CdS nanocomposite samples. The Tg values
corresponding to PS/PMMA blends & PS/PMMA/CdS
nanocomposite samples are tabulated in Table 1.
This study has demonstrated that in polymer blend/
nanocomposite samples, glass transition temperatures of
corresponding phases are significantly improved. This
effect is similar to those reported in the work of Chung et
al. [6]. According to their reported work, change in the
Tg is attributed to the change in the viscosity of the PS
phase. The enrichment of nanoparticles at interfaces be-
tween the polymeric blend phases has also been found in
numerical simulations [1,2,7,8] that indicate that there
may be an accumulation of the nanoparticles at the phase
interfaces with similar energetic interaction of nanoparti-
cles for both polymer phases. In the present study it ap-
pears that this energetic interaction between respective
polymer phases and nanoparticles is of van der waal type
interaction that restricts the mobility of polymer chains
and thus more energy is required by the system to achieve
the glass transition state and therefore an increase in glass
transition temperature of that particular polymeric phase
in respective nanocomposite series, is observed.
3.3. Thermal Conductivity Measurements
Thermal conductivity of PS/PMMA blends and their CdS
nanocomposite thin film samples (thickness 0.1 mm)
have been determined through transient plane source tech-
nique using thin film method with an input power of 0.5
W for 5 seconds at room temperature (303 K). Figure 7
shows the thermal conductivities of PS/PMMA/CdS nano-
composites as a function of weight% composition of
PMMA in PS matrix, respectively.
The values of thermal conductivities obtained for PS/
PMMA blends and their CdS nanocomposites are sum-
marized in Table 2.
The first observation is that the thermal conductivities
of studied CdS nanocomposite samples are higher than
their counterparts without CdS dispersed respective sam-
ples. As we know in non-metallic material system like
polymer and polymer blends, the thermal energy is mainly
carried by phonons, which have a wide variation in fre-
quency and the mean free paths. The heat carrying pho-
nons often have large wave vectors and mean free paths in
the order of nanometer range at room temperature. In this
way the dimensions of the nanoparticles become compa-
rable to the mean free paths which would lead to signifi-
cant improvement in phonon transport within the nano-
composite materials. The phonon confinement and quan-
tization of phonon transport results modification in ther-
mal properties. Since CdS nanoparticles having higher
thermal conductivity and act as cross-linking centers
between the polymer molecules therefore promptly sub-
serve for the phonon-phonon conduction in that respec-
tive polymer network. This causes the enhancement of
thermal conduction in CdS nanocomposites of PS/
PMMA blends.
Besides this, interfaces included in nanocomposite sam-
ples are also very important factor for consideration in
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Figure 5. SEM micrographs for studied P S/CdS, PMMA/CdS & PS/PMMA/CdS samples.
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212
(a) (b)
(c) (d)
(e)
Figure 6. ((a), (b)) Variation of Tanδ with temperature for PS & PS/CdS and PMMA & PMMA/CdS respectively; ((c)-(e))
Variation of Tanδ with temperature of PS/PMMA and PS/PMMA/CdS systems respectively.
Table 1. Glass transition temperatures of PS/PMMA & their CdS nanocomposites.
Tanδ peaks Tanδ peaks
Samples Tg-I (˚C) Tg-I I (˚C) Samples Tg-I (˚C) Tg-II (˚C)
Pure PS 113.1 PS/CdS 121.9
70PS/30PMMA 90.57 112.3 70PS/30PMMA/CdS 100.19 119.2
50PS/50PMMA 88.45 113.8 50PS/50PMMA/CdS 97.57 118.18
30PS/70PMMA 84.16 112.7 30PS/70PMMA/CdS 94.32 119.47
Pure PMMA 79.3 PMMA/CdS 89.7
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213
Table 2. Thermal conductivities of PS/PMMA/CdS nanoc omposites.
Pure & Blend samples Thermal conductivity (W/mK) Nanocomposite samples Thermal conductivity (W/mK)
Pure PS 0.149 PS/CdS 0.202
70PS/30PMMA 0.159 70PS/30PMMA/CdS 0.211
50PS/50PMMA 0.164 50PS/50PMMA/CdS 0.218
30PS/70PMMA 0.171 30PS/70PMMA/CdS 0.228
Pure PMMA 0.179 PMMA/CdS 0.234
Figure 7. Variation of thermal conductivity with weight% of PMMA in PS/PMMA/CdS nano c omposite s.
nanoparticles disturbs the molecular chain network of PS
matrix. This interruption causes decrease in covalent bond
molecular network and increase in van der waal interac-
tion within the nano-CdS dispersed PS matrix. This in-
turn induces more brittleness in the PS matrix and caus-
ing loss in strength and fracture energy of the system.
the estimation of thermal properties.
Generally, the internal interfaces impede the flow of
heat due to phonon scattering. At interface or grain bound-
ary between similar materials, the interface disorder scat-
ters phonons, while the differences in elastic properties
and densities of vibrational states affect the transfer of
vibrational energy across the interfaces between dissimi-
lar materials. As a result, the nanocomposite structures
exhibiting high interfaces densities depict low thermal
conductivity.
Figure 8(b) shows the tensile behavior of PMMA/CdS
nanocomposite sample. The tensile properties of this nano-
composite sample are also significantly improved due to
presence of CdS nanoparticles. The percentage increase
observed in Young’s modulus and ultimate tensile strength
is 40.65% and 48.75%, respectively. The fracture energy
and fracture strain of this system have also been found to
increase i.e. 0.24J and 5.9%, respectively. The improve-
ment in tensile properties of PMMA/CdS nanocomposite
is again due to the formation of compact structure. Hence
dispersion of CdS nanoparticles provides strength to
PMMA matrix. Figures 8(c)-(e) show the tensile stress
strain behaviour of 70PS/30PMMA, 50PS/50PMMA and
30PS/70PMMA along with their CdS nanocomposites,
respectively. It is observed that the interaction between
polymer blend’s molecules and nanofiller significantly
3.4. Tensile Stress-Strain Analysis
Figure 8(a) show the tensile stress-strain characteristics
of PS/CdS nanocomposite samples. It is observed that PS
matrix becomes more brittle due to the dispersion of CdS
nanoparticles. However, Young’s modulus of the PS ma-
trix remains almost constant but fracture energy of PS
matrix trims down from 0.029 J to 0.018 J. The ultimate
tensile strength and fracture strain are observed 8.84 MPa
and 0.83%, respectively for this nanocomposite.
It is seemed due to the fact that the dispersion of CdS
V. MATHUR, K. SHARMA
214
(a) (b)
(c) (d)
(e)
Figure 8. ((a), (b)) Stress-Strain behavior of PS & PS/CdS and PMMA & PMMA/CdS; ((c)-(e)) Stress-Strain behavior of
PS/PMMA & PS/PMMA/CdS samples.
alter the tensile properties of PS/PMMA blend matrix.
Figure 8(c) for 70PS/30PMMA blend and its CdS nano-
composite further suggest that rich portion of blend ma-
trix (70%) i.e. PS phase becomes more brittle on inter-
acting with dispersed CdS nanoparticles. This inturn re-
duces Young’s modulus, ultimate strength, fracture en-
ergy and fracture strain of this nanocomposite system.
Figure 8(d) curves (a) and (b) present the tensile prop-
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Table 3. Tensile properties of PS/PMM A/CdS nanoc omposite samples.
PS 70PS/30PMMA 50PS/50PMMA 30PS/70PMMA PMMA
Samples Without
CdS With CdS Without
CdS With CdSWithout
CdS With CdSWithout
CdS With CdS Without
CdS With CdS
Young modulus (GPa) 16.64 15.41 22.05 19.05 23.29 9.63 27.92 29.17 6.42 9.03
Ultimate strength
(MPa) 11.64 8.84 14.01 11.20 7.39 5.14 4.45 12.03 7.63 11.35
Fracture energy (J) 0.029 0.018 0.028 0.019 0.012 0.033 0.002 0.039 0.018 0.24
Fracture strain (%) 1.034 0.83 0.86 0.78 0.62 2.09 0.29 1.12 1.22 5.94
erties of 50PS/50PMMA blend and 50PS/50PMMA/CdS
nanocomposite. In this nanocomposite system both the
phases of PS and PMMA are defined in equal proportion
with higher degree of immiscibility. Dispersion of CdS
nanoparticles induces increase in brittle nature of PS
phase and increase in ductility of PMMA phase. Thus the
overall effect appears as decrement in Young’s modulus
and ultimate tensile strength and increment in fracture
energy and fracture strain properties of this nanocompo-
site system.
Figure 8(e) shows the tensile stress strain behavior of
30PS/70PMMA/CdS nanocomposite along with 30PS/
70PMMA blend. In this case also, the tensile properties
have been observed significantly influenced from domi-
nant PMMA/CdS phase. This nanocomposite system pre-
sent such a compatible system for which along with
Young’s modulus and ultimate strength, fracture energy
and fracture strain are also observed enhanced. Table 3
presents the systematic results evaluated from tensile
property of PS/PMMA/CdS nanocomposite system.
The results obtained for PS/PMMA/CdS nanocompo-
sites are principally explained on the basis of compact-
ness and interaction between nanoparticles & polymeric
phases of the nanocomposite systems. When CdS nanopar-
ticles are dispersed into the polymer matrix, they tend to
settle down at the voids & interface positions and act as
cross-linking centers between the polymer molecules.
These CdS nanoparticles behave as a surfactant, reducing
the interfacial energy between the two polymer phases
[1,2]. Since PS/PMMA blend systems are immiscible,
the incorporation of the CdS nanoparticles with different
composition dependent morphological blend structures
present tailored tensile properties. Bonding between nano-
particles and polymer matrix leads good adhesion be-
tween matrix and filler [8] leading to higher density of
nanocomposite structure. In this way compactness of
composite is directly related to their respective prominent
elastic properties.
4. Conclusion
This study showed that the thermal and mechanical prop-
erties of PS/PMMA immiscible polymer blends are sig-
nificantly influenced by the dispersion of CdS nanofiller
particles, but the effect is composition dependent. The
glass transition temperature (Tg) of the respective poly-
meric phases embedded with nanofiller CdS have been
found to be shifted towards higher temperature side. The
thermal conductivity of CdS nanocomposites is found to
increase because of the formation of bridged polymer
network through higher thermal conducting element i.e.
CdS nanoparticles, leading to the increase in the pho-
non-phonon interaction within the nanocomposite matrix.
It is found that PS matrix become more brittle due to
dispersion of CdS nanoparticles where as compactness of
PMMA matrix enhances. An increment in fracture en-
ergy and fracture strain of 50PS/50PMMA/CdS nano-
composite is also observed.
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