Download Electrical properties and structure of polymer composites with

ELECTRICAL PROPERTIES AND
STRUCTURE OF POLYMER COMPOSITES
WITH CONDUCTIVE FILLERS
2. Filled polymer blends: influence of
morphology on spatial distribution
of filler and electrical properties
Ye. P. Mamunya
Institute of Macromolecular Chemistry
National Academy of Sciences of Ukraine
Kiev, Ukraine
[email protected]
2
Types of the polymer blend structure
• Immiscible polymer blends create
the two-phase systems with variety
of morphologies, for example:
a) dispersed structure (TPU/PP=80/20)
b) matrix-fiber structure (SAN/PA=70/30)
c) lamellar structure (PP/EPDM=80/20)
d) co-continuous structure (PS/PE=75/25)
• Type of structure mainly depends
on the fraction ratio of components,
processing (technological regimes)
and viscosity ratio.
D.A. Zumbrunnen. S. Inamdar. Chem. Eng. Sci., 2001, 56, 3893–3897.
P. Potschke, D. R. Paul. J. Macromol. Sci., Part C-Polym. Revs.,
2003, C43, 87-141.
3
Forming of the blend structure during processing
• Schematic description of the
blend morphology development along the axis of a twinscrew extruder for a polymer
pair AB.
• Conditions:
1) φB > φA, ηA > ηB
2) φB < φA, ηA < ηB
J.K.Lee, C.D.Han. Polymer, 1999, 40, 6277–6296.
J.K.Lee, C.D.Han. Polymer, 2000, 41, 1799–1815.
P. Potschke, D. R. Paul. J. Macromol. Sci., Part C-Polym. Revs.,
2003, C43, 87-141.
4
Structural model of development of the blend
morphology depending on the componets ratio
A
B
• Depeding on fraction ratio A/B of
A
B
A
A
A
B
B
B
A
B
components
the morphology of
polymer blend changes from the
insulated inclusions of polymer B
within polymer A (at low content of
polymer B) to the co-continuous
structure at equal content of the
phases
and
further
to
the
inclusions of polymer A within
polymer B (at low content of
polymer A).
5
Morphology of polymer blend and derived
mechanical properties
Polymer blend based on:
• Polymer A:
cellulose acetate butyrate
• Polymer B:
polyoxymethylene
σt, σy, kg/cm
Polymer A / Polymer B = 100 / 0
Polymer A / Polymer B = 50 / 50
ε, %
Polymer A / Polymer B = 99 / 1
σi, kg cm/cm
2
2
Polymer A / Polymer B = 20 / 80
Content of polymer B
Polymer A / Polymer B = 95 / 5
Polymer A / Polymer B = 0 / 100
Ye. P. Mamunya, E. V. Lebedev, E. N. Brukhnov, Yu. S. Lipatov.
Vysokomolek. Soed., 1979, A21, 1008-1013 (in Russian).
There
are
three
regions
of
mechanical
properties
of
this
polymer blend that strongly depend
on the structure: (1) corresponds to
inclusions of B in A; (2) the polymer
components
behave
as
the
connected phases; (3) corresponds
to inclusions of A in B.
6
Interfacial region in polymer blends
δs
a
δt
b
• Thickness of the interfacial layer δs is 2-10 nm and
comparable with length of molecular segment.
• Thickness of the transition layer δt is up to 1 μm
and defined by conditions of the structure forming.
b
a
Polymer blend
PE-POM = A-B
A
B
a) TmA<Tproc<TmB
δs
δt
δs
δt
Temperature of
processing
a
A
A/B
b) TmA<Tproc>TmB
B
b
Yu.S. Lipatov. Physical chemistry of filled polymers.
Moscow: Chemistry, 1977 (in Russian).
Yu.S. Lipatov, Ye. P. Mamunya, E. V. Lebedev, N.A. Sytenko,
G.Ya. Boyarskii. Vysokomolek. Soed., 1981, B23, 282-287 (in
Russian).
7
Filling of polymers and polymer blends
Usually the polymers can be filled for several reasons:
• To reduce the cost of polymer product. The cheap and widespread
fillers are used;
• To improve the mechanical characteristics (toughness, bending
strength etc.) of polymer. The reinforcing fillers are used.
• To obtain the colored polymer product. The pigments are used.
• To create the composite material. Content of filler in a polymer is very
high (close to the limit of filling). The fiber fillers are often used.
• To impart new properties to the polymer. The functional fillers are
used, for example conductive filler (carbon black, dispersed metals) that
transforms filled polymer from insulating to conductive state.
• Filing of polymer blend with functional filler suggests additional
potential in properties of the functional polymer systems because of
heterogeneous structure of the polymer matrix that changes the spatial
distribution of the filler. It is very important for conductive polymer
systems.
8
Influence of heterogeneity of polymer blend on the
spatial distribution of filler
• Immiscible polymer blend is two-phase system with developed interfacial
region
• Heterogeneity of polymer blend can influence on spatial distribution of filler in
the polymer matrix
• Generally 4 cases of spatial distribution of the filler can be realized in the
polymer blend:
Filler
occupates
both of
polymer
phases
Filler
occupates
one of two
polymer
phases
Filler
occupates
second of
two polymer
phases
Filler is
localized on
the
interface
filling
• Last three cases of filler distribution are of the highest interests because of
nonuniform distribution of filler.
9
Influence of processing on the spatial
distribution of filler
polymer 1
polymer 2
filler
processing
Generally 5 methods of filling of
the polymer blend exist:
filler → polymer 1
polymer 2
FPB
1
polymer 1
filler → polymer 2
FPB
2
filler → polymer 1
filler → polymer 2
FPB
3
polymer 1
filler → polymer 2
filled
polymer
blend
filler +
FPB
polymer 1
+
FPB
4
5
polymer 2
Methods 1- 4 are two-stages,
method 5 is one-stage.
Electrical properties of composites depend on the conductive
filler distribution and consequently on the method of filling
Filler
occupates
both of
polymer
phases
Filler
occupates
one of two
polymer
phases
Filler
occupates
second of
two polymer
phases
Filler is
localized
on the
interface
Correlation structure-conductivity in filled
polymer blends
Variation of the composite composition leads to phase inversion in such a way:
Nonconductive matrix
with inclusions of
conductive phase
Co-continuous structures
of conductive and nonconductive phases
Conductive
matrix
with inclusions of
nonconductive phase
Structure
Conductivity
First, the composite is
not conductive
Separated inclusions are merged
creating the continuous filled phase
which provides the appearance of
jump of the conductivity
When conductive phase
becomes a matrix, the conductivity increases slowly
due to the decrease of the
nonconductive inclusions
10
11
Structure and conductive properties of filled
polymer blend
nonconductive
conductive
Conductivity, log σ
Region 3
Region 1
Region 2
percolation
threshold
ϕc
Filler volume fraction, ϕ
Conductivity of filled polymer blend
is a function of the filler content
and reflects its heterogenious
structure.
Region 1 – the composite is nonconductive, the polymer blend consists of
nonconductive polymer 1 with inclusions
of filled conductive polymer 2 phase.
Region 2 – Co-continuous conductive and
non-conductive unfilled polymer 1 – filled
polymer 2 phases. It is a region of
percolation, the conductivity sharply
increases at ϕ > ϕc.
Region 3 – Structure of composite
consists of conductive matrix (filled
polymer
2)
with
inclusions
of
nonconductive polymer 2 phase. The
conductivity slowly increases.
J. Feng, C-M. Chan. Polym. Eng. Sci., 1998, 38, 1649-1657.
12
Double percolation phenomena
PP
The conception of double percolation first was
proposed by Sumita in 1992.
• The system is over percolation threshold and
conductivity exists when two conditions are fulfilled:
HDPE
1 - continuity of conductive filler (network 1) within
the polymer phase;
2 - continuity of filled conductive phase (network 2)
within the polymer matrix.
HDPE
network 1
PMMA
network 2
•
M. Sumita, K. Sakata, Y. Hayakawa, S. Asai, K. Miyasaka,
M. Tanemura. Colloid. Pol. Sci., 1992, 270, 134-139.
If one of two networks is destroyed then the
composite becomes nonconductive.
13
The main conditions to realize the irregular spatial
distribution of filler in polymer blend
3 factors define the spatial distribution of
filler in the two-componets polymer matrix:
Thermodynamic
factor
Kinetic factor
Processing
factor
Relationship between interfacial tensions
polymer 1 – filler (γp1f), polymer 2 – filler (γp2f)
and polymer 1 – polymer 2 (γpp)
Relationship between viscosities of polymer 1
(ηp1) and polymer 2 (ηp2)
Methods of the filler introduction into the
two-components polymer matrix
14
Influence of surface tension on the morphology of
filled polymer blend
Wetting coefficient
γA-CB, γB-CB – interfacial tension
γ A−CB − γ B −CB
ω=
γ A− B
PP
HDPE
polymer-filler
γA-B – interfacial tension
polymer-polymer
Conditions of filler ditribution
PP
PMMA
HDPE
ω>1
-1 < ω < 1
ω < -1
CB is distributed within B phase
CB is distributed at the interface
CB is distributed within A phase
Components of
polymer blend
HDPE – CB
PP – CB
PMMA – CB
HDPE – PP
HDPE – PMMA
PMMA - PP
Parameters, mJ/m2
γp
γpf
25.9
20.2
28.1
-
13.1-12.2
17.1-16.7
12.2-14.6
-
γpp
1.2
8.6
6.8
γCB = 55 mJ/m2
PMMA
M. Sumita, K. Sakata, S. Asai, K. Miyasaka, H.Nakagawa.
Polym. Bull., 1991, 25, 265-271
15
Influence of the thermodynamic factor
Behaviour of the filler particle on the boundary
between components in polymer blend
Polymer 1
Polymer 2
γp1f > γp2f + γpp
Fowkes eq.
Polymer 1
Polymer 2
γp2f > γp1f + γpp
Polymer 2
γ pf =γ p +γ f − 2⋅ (γ ⋅γ
d
p
γp1f < γp2f + γpp
γp2f < γp1f + γpp
)
d 0,5
f
(
− 2⋅ γ ⋅γ
p
p
)
p 0,5
f
Owens and Wendt eq.
0
log
S/m)
lg (σ(σ,
, См/м
)
Polymer 1
Interfacial tensions polymer–filler can be
calculated by Fowkes equation or Owens
and Wendt equation
PP/PE-CB, ϕc=0.05
PE/PP-CB, ϕc=0.05
PE-CB, ϕc=0.09
PP-CB, ϕc=0.05
ПП/ПЭ-сажа
метод А
PE/POM-CB, ϕc=0.03
POM-CB, ϕc=0.12
ПП/ПЭ-сажа
метод Б
ПЭ/ПОМ-са жа
метод А
концентра т
ПП-са жа
-4
конце нтра т
ПОМ-сажа
концентра т
ПЭ-сажа
-8
2
1
0,1
5
4 3
а
-12
-16
0,0
6
0,2
б
0,3
0,0
0,1
0,2
в
0,3
0,0
0,1
0,2
0,3
объемная
доля наполнителя,
Filler volume
fraction, ϕ ϕ
c
Ye.P. Mamunya. J. Macromol. Sci.-Phys., 1999, B38, 615-622.
16
Interfacial interaction between polymer and filler
σ = σ0 (ϕ - ϕc)t
log (σ, S/m)
Components of
polymer blend
1 – PP-CB
2 – PE-CB
3 – PS-CB
4 – PMMA-CB
5 – PA-CB
0.045
0.055
0.070
0.100
0.255
Parameters, mJ/m2
γp
γpf
30.0
35.5
40.7
43.4
46.6
3.76
2.13
1.07
0.69
0.35
γf- γp
25.0
19.5
14,3
11.6
8.4
γCB = 55 mJ/m2
• Shift of ϕc and deviation from equation
Filler volume fraction, ϕ
PP
PP – CB
PE – CB
PS – CB
PMMA – CB
PA-CB
ϕc
(curves 5 and 5a) are observed in the polymer
row PP-PE-PS-PMMA-PA
filled with carbon
black.
PE
• Interaction polymer-filler becomes stronger in
the row PP-PA.
• The higher difference (γf - γp) or interfacial
tension γpf, the more branched conductive
structure can be formed. This effect provides
low value of percolation threshold ϕc .
K. Miyasaka , K. Watanabe, E. Jojima, H. Aida, M. Sumita,
K. Ishikawa. J. Mater. Sci., 1982, 17, 1610-1618.
E.P. Mamunya, V.V. Davidenko, E.V. Lebedev. Composite
Interfaces, 1997, 4, 169-176.
17
Model approach of polymer-filler interaction
Filler packing density
coefficient - packing-factor
σm
σ = σ0 (ϕ - ϕc)t
F=
Vf
V f + Vp
Proposed
model
changes eq. 1 and 2
by eq. 3. Exponent k
includes the value of
interfacial tension γpf
log σ
1
σc
σp
2
ϕc
F
0,5
log σ
3
2
t
γ pf =γ p +γ f − 2⋅ (γ pd ⋅γ df ) − 2⋅ (γ pp ⋅γ fp )
Filler content
1
σ = σ c + (σ m
⎛ ϕ −ϕc ⎞
⎟⎟
− σ c )⎜⎜
−
F
ϕ
c ⎠
⎝
3
⎛ ϕ − ϕc ⎞
⎟⎟
logσ = logσ c + (logσ m − logσ c ) ⋅ ⎜⎜
F
ϕ
−
c ⎠
⎝
k
0,5
K = A +B⋅γpf
k=
K ⋅ϕc
(ϕ − ϕ c )n
Wetting of the filler by polymer: 1-poor; 2 – intermediate; 3 - absolute
ϕc1
ϕc2 F1
F2
ϕc3=F3
E.P. Mamunya, V.V. Davidenko, E.V. Lebedev. Composite
Interfaces, 1997, 4, 169-176.
M.L. Clingerman, E.H. Weber, J.A. King, K.H. Schulz.
J. Appl. Polym. Sci., 2003, 88, 2280-2299.
In the first case the system has low values of ϕc1 and F1. In the last
case the percolation appears only at value ϕc3=F3 because the
particles are separated by polymer interlayers. PP-CB is closer to
the first case, PA-CB is closer to the last case.
18
Influence of the kinetic factor
• If the polymer components have big difference in the viscosity values
(ηp1 >> ηp2) then kinetic factor is essential.
• During processing through polymer melt, under shear stresses, the
filler is captured by polymer component with lower viscosity.
The value of melt flow index
(MFI, g/10min) for polymers
PE
– 1.6
POM – 10.9
PA
– 11.7
The model and the real structure for the
filled polymer blend PE/POM-Fe
ϕ > ϕc
ϕc = 0.09
ϕc = 0.21
ϕc = 0.24
ϕc = 0.29
ϕ >> ϕc
log (σ, S/m)
ϕ < ϕc
0
PE/POM-Fe,
PE-Fe,
POM-Fe,
PA-Fe,
-4
-8
1
2
0,1
0,2
3
4
-12
PE
POM-Fe
-16
0,0
0,3
0,4
Filler volume fraction, ϕ
Ye.P. Mamunya, Yu.V. Muzychenko, P.Pissis, E.V.
Lebedev, M.I. Shut. Polym. Eng. Sci., 2002, 42, 90-100.
19
Phase inversion in polymer blends
Conductivity jumps up when the co-continuous structure of polymer phases is
appears. There is a region of phase inversion. Existence of such structure in filled
polymer blend is necessary to obtain the conductive system.
Definition 1:
Co-continuity means the coexistence of two continuous structures within the same volume;
both components have three-dimensional spatial continuity.
Definition 2:
Co-continuous structures are those in which at least a part of each phase forms a coherent
continuous structure that permeates the whole volume.
Φ1=φ1/(φ1+φ2) – continuity index
• The degree of co-continuity (or continuity
index) Φ of a specific phase is the ratio between
the extracted mass of this phase and the total
content, assuming self-supporting of residuary
material after extraction.
P. Pötschke, D.R. Paul. J. Macromol. Sci.-Part C., 2003, C43, 87-141.
20
Definition of co-continuous phases by extraction
Method of selective extraction
• Extraction experiments are easy
and convenient way to check for cocontinuity when the components
are soluble in the specific solvents.
PS/PE-CB
PA6/ABS
PA6 phase is extracted
• A
co-continuous structure is
present if the part remaining after
dissolution of the other component
is selfsupporting and if its mass is
approximately that in the original
blend.
PS
PE-CB
PBT/(PE-co-AA)-CB
PE
PS
(PE-co-AA)-CB phase is
extracted
F. Gubbels, S. Blacher, E. Vanlathem, R. Jerome, R. Deltour,
F.Brouers, Ph. Teyssie. Macromolecules, 1995, 28, 1559-1566.
P. Pötschke, D.R. Paul. J. Macromol. Sci.-Part C., 2003, C43,
87-141.
C. Lagreve, J.F. Feller, I.Linossier, G. Levesque. Pol. Eng. Sci.,
2001, 41, 1124-1132.
21
Phase inversion in PE/PC-CNT polymer blend
Ratio PE/PC-CNT
80/20
40/60
60/40
20/80
Morphology of PE/PC-CNT composite after
extraction of PC-CNT phase by chloroform.
P. Pötchke, A.R. Bhattacharyya, A. Janke. Polymer
2003, 44, 8061-8069
22
Regions of phase inversion in different polymer blends
Polymer
blend
Intervals of
phase
inversion
(content of
filled phase)
Type of
conductive
filler
Localization
of filler
Refs.
PMMA/PP
20-60
CB, 10 %
PMMA+interf.
[1]
PS/SIS
70-80
CB, 2 %
PS
[2]
CPA/PP
50-70
CB, 2 %
CPA
[3]
PE/PS
10-60
CB, 4 %
PE+interface
[4]
LDPE/EVA
50-80
CB, 18 %
LDPE+interf.
[5]
PC/HDPE
30-80
MWCNT, 2 % PC
POM/PE
30-50
Fe, 32 %
POM
CPA/PP
10-20
Fe, 35 %
CPA
• Depending on kind of the polymer
components the intervals of phase
inversion are different.
• Filler can be localized in one of two
polymer phases or on the interface.
[6]
our
study
Localization of filler is defined by
both thermodynamic and kinetic
factors.
Conditions
of
phase
inversion are defined by kinetic
factor.
1. M. Sumita, K. Sakata, Y. Hayakawa, S. Asai, K. Miyasaka, M. Tanemura.
Colloid Polym. Sci., 1992, 270, 134-139.
2. R. Tchoudakov, O. Breuer, M. Narkis. Polym. Eng. Sci., 1996, 36, 1336-1346.
3. R. Tchoudakov, O. Breuer, M. Narkis. Polym. Eng. Sci., 1997, 37, 1928-1935.
4. F. Gubbeles, S. Blancher, E. Vanlathem, R. Jerome, R. Deltour, F. Brouers,
Ph.Teyssie. Macromolecules, 1995, 28, 1559-1566,.
5. G. Yu, M.Q. Zhang, H.M. Zeng, Y.H. Hou, H.B. Zhang. Polym. Eng. Sci.,
1999, 39, 1678-1688.
6. P. Potschke, A.R. Bhattacharyya, A. Janke. Polymer, 2003, 44, 8061-8069.
23
Viscosity ratio A/B
Conditions of phase inversion in polymer blends
Continuous
phase of B
1
C
co
o-
in
nt
us
uo
s
se
a
ph
Continuous
phase of A
ηA ϕA
>
ηB ϕB
Phase of B is continuous
ηA ϕA
<
ηB ϕB
Phase of A is continuous
ηA ϕA
=
±C
ηB ϕB
Region of phase inversion
C is width of phase inversion region
1
Volume ratio A/B
2,0
100
Continuous
phase 2
Viscosity ratio, η1/η2
1,0
10
η1 ϕ 2
⋅
η 2 ϕ1
0,0
1
-1,0
0.1
-2,0
0.01
0
0/1
Continuous
phase 1
0,5
0,75
0.5/0.5
Volume fraction ratio, ϕ2/ϕ1
0,25
≥1
phase 2 continuous
≤1
phase 1 continuous
≈1
dual phase continuous
D.R. Paul, J.W. Barlow. J. Macromol. Sci.-Rev. Macrom.
Chem., 1980, C18, 109-168.
1
1/0
G.M. Jordhamo, J.A. Manson, L.H. Sperling. Polym. Eng. Sci.,
1986, 26, 517-524.
24
Morphology development of filled polymer blends
PE
4Fe
70 μm
7Fe
PP
3Fe
POM-Fe
PE/POM-Fe
12Fe
23Fe
28Fe
15Fe
30Fe
PP/CPA-Fe
CPA-Fe
5Fe
18Fe
7Fe
10Fe
Region 1
Region 2
Region 3
Nonconductive phase
is a matrix.
Conductive phase is in
a form of separated
inclusions
Region
of
phase
inversion.
Conductive and nonconductive phase are
co-continuous.
Conductive phase is a
matrix.
Nonconductive phase
is in a form of separated inclusions.
25
Structure model of conductive phase
•Such a structure is a result of two stage processing and a big difference of the
viscosity of polymer components. The filler is introduced in the low viscous
polymer at the first stage and remains in it during second stage of processing.
• Several kinds of phase structure can be formed in the composite:
PE/POMPE/POM-Fe
PP/CPAPP/CPA-Fe
Conductive phase is
distributed in the form
of separated inclusions.
Nonconductive phase is
a matrix.
PE/POMPE/POM-Fe
Conductive and nonconductive
phases
create the co-continuous structure.
The
composite
is
conductive
with
conductivity σ1.
PP/CPAPP/CPA-Fe
Conductive
phase
more branched.
is
The
composite
is
conductive
with
conductivity σ2 > σ1 at
lower content of filler
than in previous case.
Relationship of viscosities for the systems:
MFIPP/MFICPA = 4.2·10-2
MFIPE/MFIPOM = 1.5·10-1
PE/POMPE/POM-Fe
PP/CPAPP/CPA-Fe
Conductive phase is a
matrix,
nonconduc-tive
phase is in the form of
separated inclusions.
26
Conductivity of PP/CPA-Fe and PE/POM-Fe composites
σm
σ − σ c ⎛ ϕ − ϕc ⎞
⎟⎟
= ⎜⎜
σ m − σ c ⎝ F − ϕc ⎠
σc
• Composites demonstrate two-step
percolation behavior with plateau in
the region of phase inversion which
corresponds to the co-continuous
structure of phases.
t
parameters of equation
ϕc
σc , σm , ϕc , F
F
• For PE/POM-Fe the plateau located
in the interval 12-18 vol.% of Fe.
Fe
• For PP/CPA-Fe the plateau located
in the interval 6-10 vol.% of Fe.
Fe
Conductivity, log (σ, S/cm)
-2
• It is possible to calculate theoretical curves separately for region 2
and region 3 (dotted curves in Fig.)
with the values of parameters:
-5
-8
PP/CPA-Fe
-11
PE/POM-Fe
PE/POM-Fe
Parameters
ϕc,% F, % log σc log σm
PE/POM-Fe
PP/CPA-Fe
-14
t
region 2
region 3
3.2
2.1
5
5
35 -15.5 -2.48
35 -15.5 -2.32
1.7
13
9
9
12 -15.0 -7.58
32 -15.0 -2.51
PP/CPA-Fe
-17
00
0,1
10
0,2
20
Filler content, ϕ, %
0,3
30
0,4
40
region 2
region 3
27
Features of phase structure and conductivities of
PP/CPA-Fe and PE/POM-Fe composites
PP/CPA-Fe
PE/POM-Fe
• Structure in the region of
phase inversion
more branched
less branched
• Region of phase inversion
plateau 7-10 vol.%
plateau 12-18 vol.%
• Percolation threshold
lower (5 vol.%)
higher (9 vol.%)
• Conductivity on a level of
plateau
higher (8·10-7 S/cm)
lower (6·10-8 S/cm)
• Maximal conductivity σm
at ϕ = F (conductivity of a
master batch)
equal (3·10-3 S/cm)
equal (3·10-3 S/cm)
28
100PP
80PP/13CPA-7Fe
71PP/19CPA-10Fe
57PP/28CPA-15Fe
20PP/52CPA-28Fe
65CPA-35Fe
100CPA
5
3
100ПЭ
Tm PP
Expansion / Deformation, L, %
Expansion / Deformation, L, %
Thermomechanical analysis (TMA) of PP/CPA-Fe
and PE/POM-Fe composites
Tm CPA
1
-1
Tm PE
Tm POM
78PE/15POM-7Fe
62PE/26POM-12Fe
3
53PE/32POM-15Fe
28PE/49POM-23Fe
2
68POM-32Fe
100POM
1
0
-1
0
40
80
120
Temperature,
160
0C
200
0
40
80
120
Temperature,
160
200
0C
• In the region of phase inversion the systems PP/CPA-Fe and PE/POM-Fe
have two peaks of Tm which correspond to the melting point of each
polymer phase.
• The slope of TMA curves depends on the composite composition for the
system PE/POM-Fe whereas for the system PP/CPA-Fe slope is equal for
all compositions.
29
Thermal expansion of PP/CPA-Fe and PE/POM-Fe
composites
PE/POM-Fe system
4
• Coefficient of thermal expansion α
undergoes a jump in the region of
phase inversion 12-18 % of Fe.
PE/POM-Fe
α⋅104, 0C-1
3
PP/CPA-Fe
• In the region 1 the values of α equal
to the α of PE (αPE = 3.10·10-4 0C-1).
2
•In the region 3 the values of α equal to
the α of POM-Fe (αPOM-Fe =1.08·10-4 0C-1).
1
PE/POM-Fe system
0
0
10
20
Filler content, ϕ, %
30
Coefficient of thermal
expansion
α=
ΔL
ΔT ⋅ L0
ΔL/ΔT is a slope of TMA
curve;
L0 is the initial size of
sample.
40
• The change of the composite
composition does not influence on the
value of α.
•It is a result of equality of the α for
polymer phases (PP and CPA-Fe):
αPP
= 1.80·10-4 0C-1,
αCPA-Fe = 1.78·10-4 0C-1.
30
Regions of phase inversion in PP/CPA-Fe and
PE/POM-Fe composites
• Relationship between content of
filler in the polymer blend and the
composition of polymer matrix.
Content of Fe in composite, vol.%
40
PP/CPA-Fe
30
PE/POM-Fe
20
region of phase
inversion
10
0
0
20
40
60
80
100
Content of CPA (POM) in polymer matrix, vol.%
Region of phase inversion:
29-50 POM in the polymer matrix
12-20 CPA in the polymer matrix
•The regions of phase inversion
are different:
- for PP/CPA-Fe system the
region of phase inversion is less
extended and shifted to low
content of CPA;
CPA
- for PE/POM-Fe system this
region is wider and located at
comparable content of polymer
phases PE and POM.
POM
31
Continuous
PP phase
101
Co-continuous
phase
100
Continuous
EPR phase
-1
10
PP/CPAPP/CPA-Fe
PE/POMPE/POM-Fe
0
0.25
0.5
0.75
Weight fraction of PP
1
MFIPP (PE)/MFICPA(POM) (190 0C, P=2.16 kg)
ηEPR/ηPP
(200 0C, γ = 5.5 s-1)
Influence of rheology on phase inversion in
polymer blends
• Intervals of phase inversion of
composites
PE/POM-Fe
and
PP/CPA-Fe were superimposed on
the plot for EPR/PP system.
• In spite of using the ratio of MFIs
instead of ratio of viscosities the
intervals of phase inversions for
the EPR/PP system and for the
PE/POM-Fe
and
PP/CPA-Fe
composites are in good agreement.
Ratio of viscosities for PE/POMPE/POM-Fe and PP/CPAPP/CPA-Fe
composites:
MFIPP/MFICPA = 4.2·10-2
-1
MFIPE/MFIPOM = 1.5·10
D. Romanini, E. Garagnani, E. Marchetti. In: Martuscelli E.,
Marchetta C., editors. New polymeric materials. Reactive
processing and physical properties. Utrecht: VNU Science
Press, 1987, p. 56-87.
32
101
Co-continuous
Continuous
phases
EPR phase
Continuous
PP phase
100
10-1
0
Continuous
POM-Fe phase
PE/POMPE/POM-Fe
Continuous
PE phase
Continuous
CPA-Fe phase
PP/CPAPP/CPA-Fe
Continuous
PP phase
0.25
0.5
0.75
Weight fraction of PP
D. Romanini, E. Garagnani, E. Marchetti. In: Martuscelli E.,
Marchetta C., editors. New polymeric materials. Reactive
processing and physical properties. Utrecht: VNU Science
Press, 1987, p. 56-87.
G.M. Jordhamo, J.A. Manson, L.H. Sperling. Polym. Eng. Sci.,
1986, 26, 517-524.
1
MFIPP (PE)/MFICPA(POM) (190 0C, P=2.16 kg)
ηEPR/ηPP
(200 0C, γ = 5.5 s-1)
Influence of rheology on phase inversions in
polymer blends
• The rule for the point of phase
inversion was calculated as well :
η1 ϕ 2
× ≈1
η 2 ϕ1
• These data (on the example of
PE/POM-Fe
and
PP/CPA-Fe
composites) display the peculiarities
of phase behavior:
- the higher is difference between
viscosities of polymer phases, the
narrower is the region of phase
inversion and more shifted to the
smaller content of low viscous
polymer phase.
33
Polymer blends for the food packaging materials
• The
value of permeability relatively to
different gases: oxygen, carbon dioxide,
water vapor are very important for the food
packaging materials.
• Using of polymer blends allows to regulate
the diffusion properties of film material.
• Rate of gas diffusion depends on phase
morphology of polymer blend.
Materials:
EVOH - copoly(ethylene-vinyl-alcohol) with
32 and 38 mole percent ethylene
Polymer blend EVOH / CoPA-6/6.9
Y. Nir, M. Narkis, A. Siegmann. Polym. Networks Blends,
1997, 7, 139-146.
34
log Resistivity
log Resistivity
PTC effect in conductive polymer systems
ϕc
Filler content
Ts
Temperature
• During heating the deconnexion of the
percolating network occurs due to the matrix
thermal expansion. This effect is reversible.
• Filled polymer is converted from conductive
to nonconductive state.
thermistances
• Ts
–
sweaching
temperature
conductive/nonconductive states.
G. Boiteux, Ye.P. Mamunya, E.V. Lebedev, C. Boullanger, A.Adamczewski,
P. Cassagnau, G. Seytre. Synthetic Metals, 2007, 157(24), 1071-1073.
for
35
PTC effect in filled polymers and polymer blends
(PVDF-CB)
Parameters of PTC dependence
Use the polymer blend as the polymer
matrix instead of the individual
polymer eliminates NTC effect.
Z. Zhao, W. Yu, X. He, X. Chen. Mater. Lett., 2003, 57, 30823088.
H.M. Zeng, Y.H. Hou, H.B. Zhang. Polym. Eng. Sci., 1999, 39,
1678-1688. (Scheme),
Thank you
for your
attention !