For Peer Review Nanocomposites Based on High Impact Polystyrene/Silver Nanoparticles: Effect of Silver Nanoparticles Concentration on the Reaction Evolution, Morphology and Impact Strength. Journal: Polymer Engineering & Science Manuscript ID: PES-10-0253.R1 Wiley - Manuscript type: Research Article Date Submitted by the Author: n/a Complete List of Authors: Morales, Graciela; Centro de Investigación en Química Aplicada, Polymer Synthesis Soriano, Florentino; Centro de Investigación en Química Aplicada, Plastic Proccesing and Technology Keywords: high performance polymers, nanocomposites, radical polymerization, nanoparticles John Wiley & Sons Polymer Engineering & Science
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For Peer Review
Nanocomposites Based on High Impact Polystyrene/Silver Nanoparticles: Effect of Silver Nanoparticles Concentration
on the Reaction Evolution, Morphology and Impact
Strength.
Journal: Polymer Engineering & Science
Manuscript ID: PES-10-0253.R1
Wiley - Manuscript type: Research Article
Date Submitted by the Author:
n/a
Complete List of Authors: Morales, Graciela; Centro de Investigación en Química Aplicada, Polymer Synthesis Soriano, Florentino; Centro de Investigación en Química Aplicada, Plastic Proccesing and Technology
Keywords: high performance polymers, nanocomposites, radical polymerization, nanoparticles
John Wiley & Sons
Polymer Engineering & Science
For Peer Review
Nanocomposites Based on High Impact Polystyrene/Silver
Nanoparticles: Effect of Silver Nanoparticles Concentration on the
Reaction Evolution, Morphology and Impact Strength.
F. Soriano-Corral, G. Morales*
Centro de Investigación en Química Aplicada (CIQA), Blvd. Enrique Reyna No.
140, 25253, Saltillo Coahuila, México.
*Presented at the III International Congress of Metallurgy and Materials, Monclova,
International Polymer Science and Technology, 15 (8), 65-67 (1988).
18. H. Sardelis, H.J. Michels, G. Allen, Polymer, 28, 244-250 (1987).
19. J.L Amos, Polym. Eng. And Sci., 14,1 (1974).
20. H. Keskkula, Plastics and Rubber: Materials and Applications. May., 6 (1979).
Page 17 of 32
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Evolution of a) monomer conversion vs reaction time and b) free PS Mn as a function of monomer
conversion for blank HIPS (HIPS1) and HIPS/silver nanocomposites (error bars 5%).
43x20mm (600 x 600 DPI)
Page 18 of 32
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Figure 2. Evolution of free radicals concentration with monomer conversion for blank HIPS (HIPS1) and HIPS/Silver nanocomposites.
64x58mm (600 x 600 DPI)
Page 19 of 32
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Figure 3. Calculation of the initial initiator concentration through adjusting the experimental conversion values vs reaction time data by using a mathematical model, for a) blank HIPS (HIPS1)
and for b), c) and d) HIPS/silver nanocomposites with 0.025, 0.10 and 1.0 wt-% of silver, respectively.
171x148mm (600 x 600 DPI)
Page 20 of 32
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Figure 4. Plot of monomer conversion as a function of reaction time for blank HIPS(HIPS1), HIPS with 1 wt-% silver (HIPS1-1) and HIPS with 0.2 wt-% surfactant alone (HIPS1-0.2D2) used to
Figure 5. Plot of GD as a function of a) monomer conversion and b) reaction time, for blank HIPS (HIPS1) and HIPS/Silver nanocomposites.
75x38mm (600 x 600 DPI)
Page 22 of 32
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Figure 6. Developed morphology structures before (left column), during (middle column) and after (right column) the phase inversion point during the synthesis of HIPS/Silver nanocomposites; a)
HIPS1, b) HIPS-0.025, c) HIPS-0.10 and d) HIPS-1.0 (scale bar 1µm). 150x189mm (300 x 300 DPI)
Page 23 of 32
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Figure 7. Micrographs of the morphology structure for (a) blank HIPS (HIPS1) and (b, c, d) HIPS/Silver nanocomposites with 0.025, 0.10 and 1.0 wt-% silver, respectively (scale bar 1 µm).
150x158mm (300 x 300 DPI)
Page 24 of 32
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Table 1. Kinetic equations considerd in the mathematical model according to [13].
Chemical Initiation
⋅⋅
⋅⋅
⋅
→+
→+
→
0
1
PPI
SStI
2II
i2
i1
d
k
k
k
Thermal Initiation ⋅
→ 1S2St3 i0k
Propagation
⋅⋅
−
⋅⋅
⋅⋅
−
→+
→+
→+
n
k
n
k
s
k
s
PStP
PStP
SStS
p
p0
p
1
10
1
Transfer to Monomer
⋅⋅
⋅⋅
⋅⋅
+→+
+→+
+→+
1'
0
1
1S
SPStP
SPStP
S)(PStS
fm
fm
fm
k
kn
ks s
Transfer to the rubber
⋅⋅
⋅⋅
+→+
+→+
0
0S
PPPP
P)(PPS
fg
fg
k
n
k
n n
Termination by coupling
PSP
)(PSS
tc
tc
S
→+
→+
⋅⋅
⋅⋅
−
knm
knns s
PSP tc''
0 →+⋅⋅ kn
PPP tc''
0 →+⋅⋅ kn
PPP tc'
→+⋅⋅ kmn
PPP tc'
00 →+⋅⋅ k
Page 25 of 32
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Table 2. Grafting Density (Nt*) and Number Average Molecular Weight ( Mn ) at the
phase inversion point for the synthesized blank HIPS and HIPS/silver nanocomposites.
HIPS1 HIPS-0.025 HIPS-0.10 HIPS-1.0
Silver content (wt-%) 0.00 0.025 0.10 1.00
Grafting density (Nt*) 1.20 0.89 0.80 NA
Mn PS free at PI (kg/mol) 81 101 90 NA
Mn PS free at PI: Average Number Molecular Weight of the PS matrix at the phase inversion point.
NA: Not applicable (the phase inversion was not reached).
Page 26 of 32
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Table 3. Grafting degree (GD), average particle diameter (Dp), volume fraction of the
disperse phase (Φ) and impact strength (IS) of the synthesized HIPS and HIPS/silver
nanocomposites.
Materials Parameter
HIPS1 HIPS-0.025 HIPS-0.10 HIPS-1.0
GD (%) 133 98 78 ND
Dp(nm) 134 157 140 ND
Φ 0.23 0.24 0.22 ND
IS (J/m) 37 34 33 66
ND: Not determined due to the absence of an established morphology
Page 27 of 32
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FIGURE CAPTION
Figure 1. Evolution of a) monomer conversion vs reaction time and b) free PS Mn as a
function of monomer conversion for blank HIPS (HIPS1) and HIPS/silver
nanocomposites (error bars 5%).
Figure 2. Evolution of free radicals concentration with monomer conversion for blank
HIPS (HIPS1) and HIPS/silver nanocomposites.
Figure 3. Calculation of the initial initiator concentration through adjusting the
experimental conversion values vs reaction time data by using a mathematical model,
for a) blank HIPS (HIPS1) and for b), c) and d) HIPS/silver nanocomposites with 0.025,
0.10 and 1.0 wt-% of silver, respectively.
Figure 4. Plot of monomer conversion as a function of reaction time for blank
HIPS(HIPS1), HIPS with 1 wt-% silver (HIPS1-1) and HIPS with 0.2 wt-% surfactant
alone (HIPS1-0.2D2) used to disperse silver nanoparticles (error bars 5 %).
Figure 5. Plot of GD as a function of a) monomer conversion and b); reaction time, for
blank HIPS (HIPS1) and HIPS/silver nanocomposites.
Figure 6. Developed morphology structures before (left column), during (middle
column) and after (right column) the phase inversion point during the synthesis of
HIPS/silver nanocomposites; a) HIPS1, b) HIPS-0.025, c) HIPS-0.10 and d) HIPS-1.0.
Page 28 of 32
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Figure 7. Micrographs of the morphology structure for (a) blank HIPS (HIPS1) and (b,
c, d) HIPS/silver nanocomposites with 0.025, 0.10 and 1.0 wt-% silver, respectively.
Page 29 of 32
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Corrections to the article entitled: “Nanocomposites Based on High Impact
Polystyrene/Silver Nanoparticles: Effect of Silver Nanoparticles Concentration on
the Reaction Evolution, Morphology and Impact Strength” by F. Soriano-Corral, G.
Morales*
We read carefully the article and took into account the editorial changes required as well
as the comments from the reviewers which are indicated in the text as follows:
Answers to the reviewer 1:
1) and 3) We included in the experimental section more discussion about the
mathematical model described by Luciani and the corresponding reference (reference
13) written in English. In this case the complete mathematical model was not included
as it is not our intention to describe in this paper the mathematical model and its
development but we included the material balance for the initiator and the monomer in
order to determine the conversion behavior and then the initial BPO concentration
during the HIPS/Silver nanoparticles composite synthesis. The model herein was used
only as a tool in order to describe the behaviors observed in the presence on AgNP’s.
It was included as well as the reference (reference 15) that was used in order to obtain
equation 4. With respect to this last equation we describe herein all the mathematical
arrangements in order to reach equation 4 but we consider that it is not necessary to
include all of them in the article text.
From the experimental data the [M*] was obtained as a function of X, where the rate of
polymerization is given by Eq. 1 (Odian, 1991):
*]][[][
MMKdt
Mdp=−
Eq. 1
Where [M] represents the monomer conversion, [M*] the concentration of free radicals and
kp the polymerization rate constant. It is known from the experimental data that:
0
0
][
][][
M
MMX
−=
Eq. 2
Page 30 of 32
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where, X corresponds to monomer conversion and [M]0 represents the concentration of
initial monomer. By re-arrangement of Eq.2,
][][][ 00 MMXM −= Eq. 3
Applying d/dt on Eq. 3:
dt
Md
dt
dXM
][][
0−=
Eq. 4
Substitution of Eq. 1 into Eq. 4 yields:
*]][[][ 0 MMKdt
dXM p=
Eq. 5
By rearrangement of Eq.5, [M*] can be calculated as (Equation 4 in the article):
dt
dX
XKM
p )1(
1*][
−
=
Eq. 6
Where the dX/dt was experimentally obtained from the derived polynomial function that
describes the evolution of X as a function of time, with a correlation equal to 0.99, where
the T
pk/35577 e100.1 −
×= is given in L/mol-s. In this case we included in the text the
corresponding reference (Reference 16)
2) On page 8, the observation made by the reviewer was wrong, the average molecular
weight increases with increasing silver nanoparticles concentration, there was a mistake
not in the text but in the corresponding Figure and it was properly changed (see Figure
1).
3) It is correct, the maximum decrease is 74% for HIPS1-1 with respect to blank HIPS.
The correction was made in the text.
Page 31 of 32
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4) In the case of HIPS with 1% AgNP’s, the values of impact strength are due
principally to the fact that in this case, the phase inversion was not reached at the
evaluated periods of time so that as the sample contains less of the PS brittle portion and
mostly PB at this point (x=0.27), the morphological final structure (core-shell) is not
formed and the rubber phase becomes crosslinked. It must be noted that in all the
HIPS/Silver nanoparticles composites synthesized (final product), the amount of rubber
is the same (8 wt-%).
5) The manuscript was now corrected by an English speaking people, so we hope there
are no more mistakes through out the text
Answers to the reviewer 2:
1) We tried to make the abstract more concise but it couldn´t be shorten so much.
2) The words “silver” and “High Impact Polystyrene” weren´t added to the keywords
list, because it didn´t exist in the manuscript center glossary.
3) More references were included about the in situ polymerization of vinyl monomers
(references 7-9) but it must be pointed out that the in situ polymerization of
heterogeneous systems in the presence of mineral or metallic nanoparticles has been
scarcely studied as it is mentioned in the introduction section.
4) We revised the introduction paragraph
5) The core shell morphologies are very well defined but we agree with the reviewer
that the “interprenetrated network” is not well defined (instead it is in accord with the
explanation given for reviewer 1, answer 4) so we changed the expression to “semi-
interpenetrated polymer network of crosslinked rubber grafted with PS” in order to be
more clear about this behavior that was previously described by Amos (1974) and
Keskkula (1979), both of them included in the text and in the references.
After considering all the corrections mention below it is our hope that the article
can be published without any further corrections. Thank you in advance.