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2004
Syntheses of polyphenylacetylene and
poly-1-hexyene with single-site catalysts
Xiaohang Xie
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SYNTHESES OF
POLYPHENYLACETYLENEAND
POLY-I-HEXYNE WITH SINGLE-SITE
CATALYSTS
Xiaohang Xie
January 16, 2004
A thesis submitted in partial fulfillment of the requirement for the Degree of
Master of Science in Chemistry
M_e_M_i_r_i___
Approved: _ _ _
Thesis Advisor
Terence Ce Morrill
Department Head
Department of Chemistry
Rochester Institute of Technology
Rochester, NY, 14623-5603
Copyright Release Form
SYNTHESES OF POLYPHENYLACETYLENE AND
POLY-I-HEXYNE WITH SINGLE-SITE CATALYSTS
I, Xiaohang Xie, hereby grant penmsslOn to the Wallace
Memorial Library, of RIT, to reproduce my thesis in whole or in part. Any
use will not be for commercial use or profit.
Signature
_X_i_a_o_h_a_n-=9,--X_ie___
Date _ _ _.~~!.~J0--1.1_
'0 -l....y_ _ _ _ _ _ __
11
Acknowledgements
I
like to thank my
would
encouragement,
Dr. Miri
and support
research
throughout my
gave me much support
also
a
help,
to thank Dr. Terence
tuition scholarship,
as well
finish my M.S. Degree
financial
during
I thank
in-law
want
support.
RIT. I
would
like
all
my
and
my
family
sister.
Finally
I
their kind
daughter,
would
help
being
Wang for preparing
the
Zheng
a
teaching
of
of
Sun
and
the
a
at
like
would
to
me
help
me
RIT for their
Tysiac, for his help
conductivity test.
my parents, my
parents
for my study here. I
the strength to
also
finish my thesis
in the Department
of
as
Chemistry,
department, Brenda Mastrangelo,
and continuous support.
to
Dr. Gerald
for giving
assistant
Chemistry
for
strength and support
all professors
and
Chemistry at RIT,
a sample
who gives me
thank
in the stockroom, the secretary
all
of
pregnant,
also want
In addition, I
to thank my lab partner, Dave
gave me
to thank my expected
friends for
of Department of
members, my dear husband
They
research.
thank the Department
also
also
in my
got
for my life. I
Morrill, Dr. K.S.V. Santhanam
the opportunity
the experiments, and Jun
soon as possible.
staff
I
at
for his guidance,
Especially after I
experiments and
guidance and support
Morrill, Head
Miri
Massoud
research work.
both for my
thank my graduate committee, Dr. Terence
Takacs for their kind
Dr.
advisor
and
my
Table
Copyright
of
Contents
ii
Release Form
iii
Acknowledgements
List
of
Figures
v
List
of
Tables
viii
List
of
ix
Abbreviations
X
Abstract
1
Introduction
1
2
Experimental
35
2.1 Apparatus Preparations
35
2.2 Reagent Preparations
37
2.3 Polymerization Procedures
43
2.4
Doping
of Polyphenylacetylene
2.5 Composites
of the
2.6 Characterization
3
Results
and
Polymer
with
47
Carbon Nanotubes
of Polymers
Discussion
of Polymer and
49
53
3.1 Polymerizations
3.2 Composites
48
53
Carbon Nanotubes
58
3.3 Selective Runs in Large Buchi Reactor
61
3.4 Characterizations
65
4
Conclusions
85
5
Future Research
88
6
References
89
List
Figure 1.1 Schematic Representation
Figure 1.2. Structures
Figure 1.3.
Insulator)
The Three
(Left to
of
1.7.
Overlapping
(A):
Conducting
Right) Illustrated Schematically in
and
in the CP Poly( acetylene).... 2
of 7r-conjugation
Some Common
of
Conductivities
3
Polymers
of-(R(H)C
IR Spectrum
Bands Located
at
740
Figure 1.8. Infrared Spectrum
Figure 1.9. NMR Spectra
of
of
of
PPA
of
Terms
of
Their Bandgaps
5
6
Various Materials
Polymerization
/ras-Polyacetylene
Figure 1.6. Geometric Isomers
Figure
Figures
Conductivity Classes (Metal, Semiconductor,
Figure 1.4. Comparison
Figure 1.5. Cis
of
=
10
CH)n-
14
Polyphenylacetylene.
cm"1
(=C-H cis)
and
(B)
760
Decomposition
cm"1
(=C-H
of
aromatic)... 24
25
Poly(l-hexyne)
and
PHX
and
the
Peaks Assignments
26
Figure 1.10. Thermal Analysis Curves
of
PPA in Nitrogen
27
Figure 1.11. Thermal Analysis Curves
of
PPA in Oxygen
29
Figure 1.12. (A). Single-walled Carbon Nanotubes
Carbon Nanotubes
(SWCNT)
(B). Multi-walled
(MWCNT)
33
Figure 2.1. ACE Burlitch No-air System for Work
Figure 2.2. Structures
of
Catalysts
and
under
Inert Atmosphere
Cocatalysts Used in the Polymerization
Figure 2.3. Reaction Schematic for the Synthesis
of
2,6-Bis(imino)
Figure 2.4. Reaction Schematic for the Synthesis
of
Iron Catalyst
Pyridyl Ligand
36
38
39
40
Figure 2.5. Toluene Distillation
Figure 2.6. The Small Reactor
Curve
Changing
Catalyst
of
of
PHX Made
Figure 3.3. IR Spectra
of
PPA Made
of
46
Set-Up
Figure 3.2. IR Spectra
Figure 3.4. IR Spectra
43
Set-Up
Figure 2.7. Large Buchi Reactor
Figure 3.1. The
42
Set-Up
with
with
PPA Made
by
Activity vs.
64
Reaction Time
65
Shirakawa Catalyst
Shirakawa Catalyst
66
Metallocene Catalyst
67
Figure 3.5. IR Spectra
of
PPA Made
by
Iron Catalyst in Small Reactor
67
Figure 3.6. IR Spectra
of
PPA Made
by
Iron Catalyst in Large Reactor
68
Figure 3.7. IR Spectra
Figure 3.8.
Figure 3.9.
Figure 3.10.
of
'H-NMR
'H-NMR
PPA Made
of
Figure 3.11. TGA Curve
Figure 3.13. TGA Curve
of
Figure 3.14. TGA Curve
by
by
PPA Made
PPA Made
of
Metallocene Catalyst in Small Reactor
71
Iron Catalyst in Large Buchi Reactor
72
Metallocene Catalyst in Smaller Reactor..
by
by
73
Iron Catalyst in Large Buchi Reactor
of PPA-CNT
PPA Made
by
Composite in Air
Iron Catalyst
..74
75
PPA-CNT Composite in Nitrogen
of
Figure 3.15. Compared TGA Curves
Figure 3.16. DSC Curve
69
Poly(l-hexyne)
of
of
Iron Catalyst
70
PPA Made
Figure 3.12. TGA Curve
by
PHX
of
of
'H-NMR
PPA-MWCNT Composite Made
76
and
in Nitrogen.
.
.77
78
Figure 3.17. DSC Curve
of
PHX-CNT Composite
79
Figure 3.18. DSC Curve
of
PPA-CNT Composite
80
Figure 3.19. GPC Curve
Figure 3.20.
UV- Vis
PPA Made
by
Absorption Spectra
of
of
Iron-based Catalyst
PPA in CHC13
81
82
List
Table 1.1. Physical Properties
Table
1.2.
(1-hexyne)
of
Tables
12
Polyacetylene
Geometric Structures
and
of
and
Number-average Molecular Weights
Polyphenylacetylene Prepared
by Fe-based
of
Poly
19
Catalysts
Table 2.1. Catalysts System in Experiments
37
Table 3.1. Polymer Yield
54
Table 3.2 Catalyst
and
Activity,
cz's-form
Table 3.3 Experimental Data
Table 3.4 Polymerizations
Catalyst
(1
10"3
x
Catalyst Concentration
of the
Percent
and
Yield
Polymerizations
with and without
of
of
Some Runs
56
Composites
Carbon Nanotubes
by Using
58
Iron
M)
59
Table 3.5. Experimental Data
Table 3.6 Additional Results
of
Polymerizations in Large Buchi Reactor
of PPA
Table 3.7. Mole Percent Distribution
Made in Large Buchi Reactor
of Four
Isomers
of PPA
61
63
83
List
CP:
Conducting Polymer
PHX: Polyhexyne
PPA: Polyphenylacetylene
of Abbreviations
Abstract
Phenylacetylene
zirconocene
iron(II)
dichloride,
In
chloride.
ethylene
all
polymerization
activities
tetrabutoxide /
aluminum
By
FTIR
and
1-hexyne
and
were polymerized
bis(indenyl)
cases,
were
methylaluminoxane
catalyst
H-NMR spectroscopy, the
determined, whereby
the catalysts led to
The
further
were
polymers
Differential
solubility
studies.
to be
M
the iron-based
TGA.
formation
by
The latter indicated the
ca.
the
2500
catalyst
Finally selected
polymers were
g/mol.
of
used
the
as
cocatalyst.
the
cis
its
activities.
polymer was
isomers (57.3%).
(TGA),
Ultraviolet
Spectroscopy (UV-Vis),
absence
any
by
of
cis-cisoidal
Gel Permeation
of
the polymer,
Chromatography
which could
tested for their electroconductivity.
and
isomer. The
nanotube composites were also made
to improve the stability
The
titanium
conventional
isomer in the
of more of
as
bis(imino)pyridyl
superseded
cases,
to trans
and
catalysts, such
Thermal Gravimetric Analysis
determined
PPA-carbon
polymers were
some
ratio of cis
characterized
was
those
and, in
Scanning Calorimetry (DSC),
molecular weights of
(GPC)
to
single-site
dichloride,
zirconium
comparable
triethyl
using
be
using
shown
by
1. Introduction
1.1
History
of
the Polyacetylenes
Since the late 1950s
Conjugated
polymers.
member of
Natta
this
employing
for its
synthesis
triethylaluminum
from
and
In 1974, Shirakawa, working
mechanically strong,
free-standing
additional research on
the synthesis
continued
to
by many groups
film
interest in conducting
much
to be desirable for this
has been known
a catalyst system prepared
number of other catalysts were shown
efficiency.
there has been
class of polymers polyacetylene
transition-metal salts
using
1960s,
early
polymers are perceived
patented a process
acetylene
and
acetylene.
titanium
since
from
He described the
of
Ito
the
and
Ikeda, found
polymer
[1, 2]. In
of polymers of acetylene and
at universities and
industry
[3,4].
The
1953,
parent
when
G.
metal alkyls and
polymerization of
Subsequently,
a
varying degrees
of
tetra(-propoxide).
polymerize acetylene with
with
purpose.
a
way to
prepare a
the last 30 years,
its derivatives has been
1.2 Conjugated Polymers
Polymers
encountered
these
are
often
envisioned
as
in everyday life. If we then
plastics
filled up
with
common
consider a
conductors
conducting polymers, CPs, (also
they
are
intrinsically conducting,
This intrinsic conductivity
H
atoms
and
conjugation
somewhat
7r-conjugation.
leading
an
Typical
conducting polymer,
as
metal
not
organic
such
These
overlap
do
of
as
N
have any
materials,
and
polymers
S,
polymers
as
polyethylene,
may think
we
of
Some
particles.
7r-electrons.
conducting
poly(aniline),
different, in
conductive
which
fillers
generally
the
Such
extended
contain
and
conjugation
sense
as such.
their other properties
and
establish
C
and
arise
delocalized
is illustrated
poly(acetylene).
representation of 7r-conjugation
representative
carbon
or
are quite
conductors)
simplistically in Figure 1.1 below for
Figure 1.1 Schematic
conducting
to
and
these
heteroatoms
simple
specifically from
of
as
sometimes called conductive polymers or conjugated
conductive polymers or organic polymeric
that
such
such
plastics,
in the CP
polymers are shown
poly(pyrrole),
polyacetylene.
in Figure 1.2.
poly(acetylene)
Among
the
and
the
poly(thiophenes) have been among the
most
studied, both scientifically and in terms
of
practical applications.
n
cis-polyacetylene
n
n
Poly(para-phenylene)
trans-polyacetylene
N
n
n
H
Poly(thiophene)
Poly(pyrrole)
-Nr-
CH=CH-
n
J
Poly( aniline)
Figure 1.2. Structures
Materials in the
Poly(p-phenylenevinylene)
of some common
world
may be
n
conducting
classified
polymers.
into three broad
categories
according to
their
temperature
room
conductors.
Basically,
conductivity
Electronic bands
the
levels closely
these
called
two
shown
electrons
room
difficult to
temperature. If the
from the
valence
vibrational
and
states, as
are
the
material
inorganic
reduced
now
or excitation
at room
a
photons; the
excited
from the
temperature
gives
/T-bonds
band in CPs. The
bandgap
vanishes, an overlap of the
filled, leading to
and
In
to
rise
e.g.
10 eV,
results
electrons
example
case
electronic
it lies between the
and an
of
to the
via
may be
excited
then
mobile
in
a
sense,
inorganic semiconductors,
band.
Normally,
conductivity in many
some
at
thermal excitation,
conduction
conducting polymers, in
become the
the
band. The gap between
Eg,
electrons are
valence
are semiconductors as a result of
overlap, the
partially
by
band for
and
"insulator"
band,
1.0 eV, then
e.g.
semiconductor.
"Doped"
conduction
bandgap
conduction
symbol
and
If the band gap is wide,
conduction
is narrow,
semiconductors.
state,
extended
bandgap
generally be
excitation
into the
band,
produce a conduction
in Figure 1.3.
excite
is termed
join to
semiconductors
of molecular electronic states.
produce a valence
"bandgap", carrying the
band into the
excitation,
electrons must
thermal
overlap to
states also
these states, is generally
electron
formed due to the overlap
are
valence electrons
above
insulators,
properties:
such
an appropriate oxidized or
their extended 7r-conjugation. Due to the
valence
is generally
band
greater
and
[3].
bonds become the
than 1 eV in most CPs. If the
valence and conduction
metallic conduction
the it
bands occurs,
with the
latter
/:'
t.,
E,
-
The three conductivity
Figure 1.3.
right)
place of
insulators,
semiconductor,
as
shown
can
metals,
in Figure
1.4
(generally
flcm),
denoted a) is the
which
section of
cross
in Siemens/cm (1 Siemen
the
can
be defined
material
section, i.e. p
=
in
reciprocal
as
the
=
of
be better
[1].
1
understood
In this
figure,
S/cm
the resistivity
drop
area,
( AE/distance) / (I/Area),
from
the
i.e.
a comparison of
conductivities
are
fi"
,
potential
question of given
(left to
classifications of materials,
fi"
represented
insulator)
bandgaps.
of their
CPs among the three broad conductivity
semiconductors and
conductivities,
(metal,
classes
illustrated schematically in terms
The
Insulalor
Semi-conductor
Metal
=
cm"1).
The conductivity
(generally denoted
across a given
distance in
when a given current passes
and
E
=
IR.
p,
units of
a cross
through this
z Log
a
Cu. Ag
Pb. Pt
(SNBr0,)x.Fe
+
5
Hg-,AsF5,Bi
iSN)x
Graphite
(TTFl(TCNQ)
iNMP)
d
(TCNQ)
d-
'd-ZnO
0
poly(p
-
phenylene)
sulfide)
poly(phenylene
d
polypyrrole
d
polythiophene
Ge
/-Si
Si
.
-5
a
trans -(CHL
-o
o>
a.
o
a
Water
cis
ZnO
-10
-
(CH)X
poly(phenylene
vinylene)
Diamond
polythiophere, polypyrrole
-15
poly(p-phenylene), poly(phenylene
sulfide)
Quartz
Teflon,
Figure 1.4. Comparison
Polyacetylenes
1)
of conductivities of various materials.
were chosen as
Polyacetylenes
polystyrene
the
subject of
are parent members of
2) Conducting polymers
of
this
research
because:
conducting polymers;
the derivatives
can
be
made
by
using
new
Ziegler-Natta
catalysts;
3)
Their
conductivities are
typically higher
than other conjugated
polymers.
Some important
applications of polyacetylenes and their
1)
Photovoltaics
2)
Diodes
3)
Batteries
4)
Electrochemomechanical
5)
Electrochromic devices
6)
Light emitting diodes
7)
Optical devices
(PVs)
8) Humidity sensors
actuators
(LED)
applications
derivatives
are
[3]:
1.3
Synthesis, Analysis
There
are
catalysts can
Shirakawa
be
various
and
tetra--butoxide is
There
pentane
the
The
is
catalyst
second
method,
After the
25% (1.9
Ti
and o.92
/ Ti
=
3-4)
M in
as
by
in the
preparation
blanket
glove
box,
is prepared, 9.5
mL
on
and
oxygen and water
1.7
in the
solvents
triethylaluminum is
under an argon
in excluding
(5.0 mmol)
the
of
the
Al)
the
of
using the
is
aged
for 1 h
[4, 5],
at
used as cocatalyst.
One method, using
catalyst.
vacuum
although
from the
mL of
of
Titanium
polymerization.
line,
entails
the
handling
triethylaluminum, very briefly in
slightly
more
air.
time-consuming,
catalyst solution.
dry, degassed
Ti(OC4H9-)4
triethylaluminum in toluene. The dark
references
and
used
for the
vacuum system
M)
From the
were
preparation
to the reactor, followed
of
many kinds
and
polymerization of acetylene was accomplished
components, titanium butoxide
more rigorous
[1,2,4-5],
acetylene
Preparations
-
methods
Schlenk tube techniques
of
polymerize
used as catalyst and
two
are
Polyacetylene
of
[5].
1.3.1 Shirakawa Method
Toluene
Properties
to
ways
Initially
used.
method
and
toluene is
and
brown-black
10.5
mL
mixture
introduced
(20 mmol)
(0.23 M in
25 C.
the best catalyst was a
critical concentration was
3
Ti(OC4H9)4-Al(C2H5)3
mmol/1. of Ti(OC4H9)4.
concentration, only a solid or a powder was obtained.
system
Below the
(Al
critical
1.3.2 Shirakawa Method
After the
a
was made
hypodermic
became
the
solution
the
polymerization
washed
film
was
syringe
order
dried
ash and
The
the
ratio
(H/C)
of
temperature.
by
[5]. The
to
-30
the
1
at
temperature
catalyst solution
cis-trans
-
1
temperature lower than
-
system.
Purification
of
remaining
with
it for
obtained
results of
78
under
the film
toluene or hexane
of
the temperature of
the
polymers.
a minute at room
prepared,
until
The
temperature
contained
less than
[5].
.06
polymers
From the
of
isomerization
polyacetylene so
out at several temperatures over a wide range
obtained
evacuating the
nitrogen gas on
.00
introduction
purification was carried out at
C. The
was
after
immediately
washing repeatedly
prevent
by blowing
configuration
polymerization
removing the
by
introduced into the
acetylene was
was observed
terminated
followed
colorless
in
was
by
and stored under nitrogen at
0.3%
film
of a polyacetylene
Polymerization
the film formed
using
temperature,
system reached constant
flask. Formation
acetylene gas.
Polymerization
higher than 150 C. See Figure 1.5.
strongly
the polymerizations
(ca.
C,
depends
-100
where
C
as
to
180C),
a\\-trans
upon
the
which were carried
all-cis polymer was
polymer resulted
at
<-78 C
cis-
/
Ti(OBu)4, AlEt3
HCEEEEECH
trans-
Figure 1.5. Cis
by
the infrared
150 C
rraHs-polyacetylene polymerization.
and
Qualitative
>
analysis of cis and/or trans contents of the polyacetylene was carried out
spectrophotometric method with
deformation band
1015
at
and
the
cis
the
C-H
use of
the trans C-H out-of-plane
out-of-plane
deformation band
at
740cm"
From the ratio,
cis and
by
the
[5]:
equations
cis content
(%)
trans contenf
where
trans contents of the polyacetylene were calculated
AC(J
and
spectrum of a
Atrans
=
(%)
100 [1
-
AC(J / (1
.30
100 [Almns I (1
represent
the
.30Am
+
absorbances of
specimen, respectively
.
10
+
.30ACW
Atrans)]
A!rans)]
the 740
and
1015
cm"1
bands in the
1.3.3 Properties
Because
ionization
of
polyacetylene
potential
?ras-polyacetylene,
ambient
conditions.
the
accelerates
relatively
taken
has
a
long
(IP). This low IP,
provides
the
conjugated
coupled with
polymer with sites
Polyacetylene is readily
oxidation process and
unaffected until much
the large free-radical
that
oxidized
i.e.,
>
can
be readily
at room
total conductivity
preoxidation,
structure, it has
electronic
of
0.15 O
the
in
oxidized under
doped
atoms per
low
population
temperature.
fully
a
UV light
polymer
is
double bond, has
place.
The powdery
10"4-
Polyacetylene
10-5
polyacetylene was shown
S/cm for the
trans
isomer
to be
10"10
and
a semiconductor with a
S/cm for the
cis polymer
experiments on polyacetylene yielded compressed pellet conductivities as
103S/cm.
conductivity
[5].
high
of
Doping
10"2
as
to
Table 1.1. Physical Properties
of
Polyacetylene.
Property
Value
Crystal structure
Cis-, density
1.16
g/cm3
Trans-, density
1.13
g/cm3
Thermal behavior
Cis-trans isomerization
145 C
Molecular
325 C
rearrangement
420 C
Thermal decomposition
Molecular
Tg, inferred from
Young's
[2]. Two
ca
properties
the important
of
preparation
dependent
polyacetylene's
Doping
Both
cis-
-40
-
0C
in the study
techniques
upon
Shirakawa
of
at
RT)
physical properties of polyacetylene are
of polyacetylene:
have
solution
insolubility. The
standard
104
x
200 Mpa (cis
problems arise
laboratory
1.3.4
other measurements
modulus
Many
from the
6-10
weight
not
listed
are
cannot
by
different
and
physical
caused
been taken into account,
characteristics
properties
variability
listed in Table 1.1
be determined because
generally for
polyacetylene
of
derived
catalyst.
Polyacetylene
and rra.s-polyacetylene can
be doped. There
12
are reasons
favoring doping
of
the
because it is
cis
increased to
are
acceptor or
donor
or
two
main
agents
doping
of
such as
like
[6-9]. Most
films
and
[7]
of
prepared
film into
WC16
methods can
or
then
these
by
dipping
used
doped
doping,
to
the dopant in
vacuum
polyacetylene
the
the
In any event,
to
dry
should
be
addition
of
doping
First is the
or
HC104. Second is the
film in THF
solution
polyacetylenes
one
of
addition of
alkali
Doping
and
according to the
Huang [6]
was carried out
toluene. The dopant is
polymer was washed several
remove
films for
washed
its conductivity is
metal
[6-9].
to dope
catalyst.
0.03 M iodine. The doped
subjected
stronger and
polyacetylene.
be simply handled. Chen
the Shirakawa
a solution of
tetrachloride, then
the
can
be
for
AsF5, Br2, h,
naphthalide or an electrochemical method
Various
mechanically
polymer.
types
p-doping agents,
n-doping
and
extend than the trans polymer.
freshly prepared
performed on
There
higher
a
flexible
more
the
residual solvent.
hour in
doped
polymer gives a good conductivity.
the PA
a saturated solution of
times with
Naarmann
minutes
polyacetylene
by immersing
a saturated solution of
three times and dried for 30
references
in
and
dry
Theophilou
iodine in
flowing
toluene
carbon
argon.
After
1.4 Isomeric Structures
of
Polyacetylene
and
Terminal Aliphatic Alkyne
Polymers
From the theoretical
point of
view, the linear
acetylene and terminal alkynes can
structures of oligomer
form four types
of geometrical
isomers,
1.6.
R(H)
R(H)
R(H)
Trans-tmnsoid
H
H
H
R(H)
H
H
R(H)
Czs-transoid
H
H
R(H)
R(H)
H
Trans-cisoid
(H)R
H
Cz's-cisoid
Figure 1.6. Geometric isomers
of-(R(H)C
=
14
CH)n-
R(H)
derived from
see
Figure
The terms
respect
cis and
to the double
stereochemistry
causes
severe
trans mean that the
bond,
about
and
the
chain
is
cis or
trans with
the single bonds. In polyphenylacetylene, the rraws-transoid form
180 degrees
by
of
the cisoid and transoid designations refer to the backbone
interactions between
trans-cisoid form
backbone
phenyl
pendant
rotation about
groups
and
can
be
to
converted
the carbon-carbon single
bonds in the
main chain.
Mohammed
signals on
intensities
and
the basis
Wazeer
of the signals.
The
models of the
the
of
the R
groups with
most strained structure.
four
geometrical
the
of various
four
the backbone
According
>
assign
of
the
the
'H-NMR
geometric
structures
aliphatic side chains
and
structures and relative
indicate that
cw-transoid
(R groups) farthest
oligomer.
13C-NMR
However,
order:
'raw.s-cisoid
>
.?ra.s-transoid
15
> cz's-cisoid
is the
apart and
the
less
czs-cisoid
to the models, the thermodynamic stability
isomers decrease in the
G's-transoid
to
attempted
of relative stabilities
most strain-free structure with
interaction
[10]
of
is
the
1.5 Synthesis
of
Polyphenylacetylene
(PPA)
and
Polyhexyne(PHX)
Catalyst
H
-c^=c-
C^CH
Cocatalyst
^^
Phenylacetylene
Polyphenylacetylene
Catalyst
H
?
C^^CH
(PPA)
-c=c-
Cocatalyst
Hexyne
There
are
[11-16]. The
the
Poly (1-hexyne) (PHX)
many
catalysts used
catalysts all
catalyst systems and
Y. S. Gal
[11]
for the
have their
their
own
polymerization of phenylacetylene and
strong
points.
Summarized below
hexyne
are some of
specialities.
carried out
the
polymerization of phenylacetylene with molybdocene
16
dichloride-organoaluminium
This
catalyst system.
polymerization of phenylacetylene to give a
showed
high
cocatalytic
The resulting
activity for the
The
relatively high
yield of polymer.
polymerization of phenylacetylene
polyphenylacetylenes were
common organic solvents.
catalyst system was effective
generally light-brown
polymer structure was
for the
EtAlC^
by CP2M0CI2.
powders and soluble
characterized
by
NMR
and
in
IR
spectroscopy.
CP2M0CI2 (0.029
the
polymerization
septum.
This
g,0.098
mmol)
ampoule, flushed
chlorobenzene
0.5 g (4.90 mmol)
of
by
adding
filtered from the
hour. The
Several
result of
runs
by precipitation with
solution and
then
dried to
which
calculated
At this ratio, the
is higher than
min after
at
were
equipped with rubber
the
addition of
solution.
excess methanol.
polymerization
polymer was
The
by
dissolved
precipitated polymers
40 C for 24
gravimetry.
CP2M0CI2
catalyst ratio
mole ratios were made.
is three based
polymer yield
at other ratios.
EtAlC^
To this solution,
80 C for 24 h. the
The resulting
introduced to
constant weight under vacuum at
using different EtAlC^ to
molecular weight.
then
solution, 0.49 mmol) to the
the experiments, the best
4280 g/mol,
30 C for 15
a small amount of methanol.
polymer yield was
(0.69 mL)
nitrogen and
PA is injected. After standing
in chloroform, followed
were
dry
with
catalyst solution was aged at
(1.224 mL, 0.4 M
was stopped
and chlorobenzene
is
about
on
77%,
From the
the polymer yield and
and molecular weight
is
S. Due
and
1-hexyne in the
A. Petit
presence of
salt, iron tripropionate
both in
[12]
and a
the
monosubstituted
l3C-NMR
and
polyacetylene
spectroscopic
catalysts
having
various
ligands:
complex, iron triacetylacetonate
samples
techniques. The
an organic
[(Fe(acac)3),
geometric structures of
investigated
were
and
the
H-NMR,
by
number-average molecular weights were
determined.
Toluene
and cyclohexane
(spectroscopic grade),
used as
the
were refluxed over and
distilled from CaH2. Fe(acac)3 (purity:
from toluene. Fe(prop)3
was synthesized
The Fe-compounds
were added
the
of phenylacetylene
polymerization
the triethylaluminum (AIE13). The
resulting
also
two iron-based
[Fe(prop)3]
combination with
IR
conducted
by
The
syringe.
monomer addition.
were
introduced first
and
were recrystallized
the required amounts of
experimental conditions
polymerizations were stopped
containing HC1 (ca. 5% wt/v) [12].
98%)
solvents,
and propionic acid.
catalyst solution was aged at
Detailed
listed in Table 1.2. The
from FeCb
polymerization
reagents
the desired temperature before
including
by
liquid
adding
concentration
a
few
cm3
of
data
are
CH3OH
Table
1.2.
(1-hexyne)
Geometric Structures
and
Number-average Molecular Weights
and
Polyphenylacetylene Prepared
by
1
Catalyst
system
PPA
Fe(acac)3-AlEt3b
a
Solvent
[Fe]
=
85
83
61000
100
95
3400
aging time
[Fe]
=
=
35
and
temperature: 25
[HX]
=
and
100
44000
39
31
27
1250
[PA]
=
2
mol.L"1
;
C;
C.
mol.L"1
mol.L"1
[PA]
;
=
2
;
Increasing
this work, the
3;
=
temperature: 30
min at
temperature: 50
C.
runs and
Fe(prop)3-AlEt3,
also
2
[Al] / [Fe]
;
determined from NMR
being
87
2;
=
temperature: 1 h at 50
Here two different
presence of
86
g/mol"1
mmol.L"1
polymerization
system,
13C-NMR
IR
;
[Al] / [Fe]
;
toluene;
aging time
are
H-NMR
g/mol"1
mol.L"1
1
=
1
M
(%)
mmol.L"1
polymerization
Solvent
[HX]
Cis
M
13C-NMR
cyclohexane;
1.15
=
(%)
H-NMR
Fe(prop)3-AlEt3a
Poly
Fe-based Catalysts.
PHX
Trans
of
and
results
their
IR
spectra.
in higher
temperature
Fe(prop)3, i.e., 50 C
different
could
play
25
a role on
listed. The
cis-
and
trans-
form
From, the Table 1.2 the first iron
percent
catalyst
molecular weight polymer.
mixture provided a cis
in the
ad
C;
results are
the temperature of the
reaction
50
case of
C,
the
Fe(acac)3
respectively.
-
catalyst
isomerization. In
is higher than in the
Nevertheless,
configuration of the
19
trans
the
resulting
used solvents
polymers.
Z. Shen
and
M. F. Farona
(ScN3/Al(I-C4H9)3)
system
hexyne. Phenylacetylene
Hexyne
25000
as
the
-
produced
32000
for
polymerization
moderately crystalline, high
relatively high
of
produced
of phenylacetylene
higher
molecular
(M).
molecular
Using
cis polymer.
weight,
about
chlorobenzene
polymers
weight
or
than
benzene.
obtained
synthesized
solubility properties,
crystallinity
a
polymerization
number average molecular weight
and was
and
by
DR.
from the ScN3
temperature but
135C. This behavior indicates
identical to that
to
naphthenate/trialkylaluminum
scandium
in the
materials
solid
solvents at room
common
catalyst
solvent
Polyphenylacetylene
in
a
the
use
was converted
rubbery
g/mol
cyclohexane and
as
[13]
a
the
the
dissolves slowly in
high degree
of
crystallinity;
is generally insoluble
o-dichlorobenzene at
indeed,
the polymer
analogous neodymium catalyst system
spectrum.
largely in
catalyst system
In the Nd
case
the
in appearance,
polymer showed about
cz's-cisoidal conformation
[13]. Shen
is
and
Farona
45%
also
carried out some reactions on phenylacetylene with other rare-earth naphthenates under
the
present reaction conditions.
Therefore,
at
The
polymers obtained all
least from these preliminary studies, that
behavior that closely
resembles
the
rare-earth
catalysts
showed a
scandium
high
cis content.
exhibits
catalytic
toward the polymerization
of
phenylacetylene.
W. E. Douglas
[14]
made
the
cyclopentadienylnickel complexes.
polymerization
Nickelocene
20
of phenylacetylene
catalyses
catalyzed
the polymerization
of
by
terminal
in the
acetylenes
linear
cyclotrimers,
conversion
absence of
after
solvent, giving, in the
oligomers
6 h
/ra5-cisoidal
and
C [14]. Then,
115
at
A
complexes also catalyze these reactions.
lower
but favors linear
conversion
the
presence of
not
(n-octane), is
Douglas'
it
report,
cyclopentadienylnickel
almost
can
a wide
reduction
be
whether
a mixture of
variety
in
temperature
reaction
formation. The
that
under
for the
in
main effect of
solvent-free
are active catalysts
results
(toluene)
by nickelocene.
reactions catalyzed
concluded
92%
with
of cyclopentadienylnickel
it is potentially coordinating
completely
compounds, in general,
phenylacetylene,
polyphenylacetylene
oligomer and polymer
solvent, regardless of
to suppress
case of
or
From
conditions
polymerization
of terminal acetylenes.
Phenylacetylene is
associated with
AlEt2CI
polymerized
as co-catalyst
of polymer per gram of nickel per
their
experimental
molecular weight
The highest
published
conditions, the
distribution
average
value
for
by
of
molecular
the
by
hour
A. S. Gruber
represents a
polymer
the
dicationic
is
polyphenylacetylene
conductivities
semi-conductor
formation
vary between
polymer.
Experimental
of the active species
[15]. The
typical activity
polymodal
(5000
fraction (5000 g/mol)
where
10"
electrical
et al
Ni(MeCN)6(BF4)2
production of
of
a
nickel
10"16
and
observations
S/cm,
200g
this system. Under
leads exclusively to the trans
polymer
weight
nickel complex
structure.
The
g/mol and
200
g/mol).
represents
the
highest
catalyst
is
employed.
The
and are characteristic of a
propose
a
mechanism
through the reaction of Ni(MeCN)6(BF4)2
with
for the
AlEt2Cl.
T. Masuda
polymerization
polymers
15000
of
et al
of
in high
[16] found
phenylacetylene.
the
yields and
when polymerized
by
The
rate,
by
In
using these
which was proportional
water
of
metal
On the
other
hand, in
the
polymerization rate and
smaller
the
activity
from
by WC^ in
WCU
molecular weight of
polymerization rate.
22
ranged
M0CI5
between 700
was smaller
formation
rate
and
15,000
polymer.
Addition
the
of
30 C.
high initial
proceeded at a
concentration.
and
than that
and ethylene chloride at
of a small
number-average
under suitable conditions.
trichloroacetic
the
produced
phenylacetylene
benzene
polymerization
by WC16,
of
initiators for the
phenylacetylene without
which reached about
polymerization
the
were effective
investigation
catalytic
monomer and
the polymer,
M0CI5
halides in benzene
increased both the
molecular weight of
this
was produced
to
and
polymer molecular weights
polymerization of phenylacetylene
amount
the
WC16
WC16. The
WC16. Polyphenylacetylene
a cyclic trimer
that
The
acid
decreased both the
more polar
the solvent,
1.6 Characterization
Generally,
of
PPA
to
several analyses are made
spectroscopy, NMR spectroscopy,
Some important
conductivity.
PHX
and
the
characterize
polymers of
TGA, DSC, GPC, UV spectroscopy
references
for the
characterizations of
PPA
interest: IR
and
and
electric
PHX
are
discussed below.
1.6.1 IR Spectra
A typical
deconvolution
the
value of
assigned
740
cis
spectrum
of
the
PPA is
absorption
760/740
to the
of
ratio
shown
in Figure 1.7
bands ranging from 730 to 780
between the
=C-H out-of-plane
deformation from
double bonds, the
%
The lowest limit
dependent
than 40%
on
the
cannot
cis
=
A740 /
of cw-content
presence of
be
5.5
PPA
evaluated
the 740
can
10"2
the hydrogen
be determined
(5.5A740
that
can
+
A760)
23
spectrum.
at
atoms
of
account
760
benzene ring
cm"1
and at
linked to the
Eq. 1 [12]:
(1)
be determined from this
band in the IR
example
Taking into
by the following
cm"1
in this way [17].
an
the band
monosubstituted
out-of-plane vibration of
cw-content of
with
cm"1.
respective absorbances of
cm"1
corresponding to the
[12]
equation
is
Cz's-contents lower
I
i
M
i
1
i
i
i
730
750
770
i
i
I
i
I
i
1
1.7.
(A):
IR
overlapping bands located
Figure 1.8
the IR
[13]
spectra of
the
at
shows
740
the
(=C-H cis)
spectrum of
polyalkylacetylenes.
cm"1
broad band in the 1650-1580
assigned
to the
alkyl
region.
group stretching
1450
and
1350
The
and
poly-
760
I
Three sharp
are assigned
I
l
i
1000
.
l
600 400
(B) decomposition
the
(=C-H aromatic) [12].
which
is
double bond
peaks at
2900
representative of
was observed as a
cm"1
-
2800
bonds. Two
to the double bond stretching vibration.
24
of
cm"1
1 -hexyne,
vibration of
i
vibrations of carbon-hydrogen
cm"1
about
1
1400
cm"1
IR
i
polyphenylacetylene.
of
spectrum
1
i
4000 3500 3000 2500 2000 1800
Figure
/ cm-i
v
cm"1
are
peaks at
3000
1800
2000
Figure 1.8. Infrared
spectrum of poly(l -hexyne)
1300
1400
lftOO
UAVENUMSER
1000
800
<00
600
(CM"1)
[13].
1.6.2 NMR Spectra
Representative
prepared
order
to
examine
spectra.
proton
in the
and
presence of
evaluate
the
'H
13C-NMR
Fe(acac)3
the amounts
spectra of
-
AlEt3
poly(l-hexye)
catalyst are shown
of trans- and c/s-structures
in PHX
ethyl enic and aromatic resonance signals observed
Therefore,
resonance
the fractional
peaks
/raws-configuration
peak areas were measured.
located up to
according to Leclere
about
et al.
25
and
6
ppm
are
polyphenylacetylene
in Figure 1.9 [12]. In
and
in the ]H-
In the
assigned
[18]. Peaks c, d,
PPA,
one needs
and
case of
to
13C-NMR
PHX,
the
to the H-C=C in
e represent
the protons in
the alkyl group. For
120
and
and
evaluated
by
the spectrum
150
the multiplets appearing between 5.5
PPA,
ppm
using the
13C-NMR
for
area of
(At), according
the
decomposed. The
are
5.8
cz's-signal at about
to the
copolymer
.
i
8
....
i
7
is
....
i
...
6
i
i
5
,
4
,
,
,
i
3
,
,
,
.
i
and
the total area
.
.
2
.
.
i
.
.
1
.
t
0
spectra of PPA and
.
i
i
.
140
.
i
i
.
120
.
.
i
.
100
.
i
.
,
.
80
i
,
60
5/ppm
PHX
and peaks assignments
26
of
(2)
spectrum of
discussion.)
8/ppm
Figure 1.9. NMR
'H-NMR
2. [17]:
following Eq
for this
not significant
(A5.g)
labeled in the figure. (In this figure, the
assignments are
for
ppm
cw-structure contents were
ppm
%c/5=104A58/16.66At
All the
8
and
[12].
.
,
i
.
40
,
,
i
20
.
,
i
0
the
Scanning Calorimetry (DSC)
Differential
1.6.3
Analysis
(TGA)
Samples in
Instruments
and
Thermogravimetry
Curve
powder
[19, 20].
form (5-15 mg)
All the thermal
were
analyzed
in
aluminum
handled in
analyses are
pans
using TA
nitrogen and oxygen
for
comparison.
DSC(
)
TG(
) DTG(
)
E
-1
-
-
300
200
100
Figure 1.10. Thermal
[19]. Both
(peaks
at
and
analysis curves of
TG
exothermic
141
and
339
C)
(peaks
at
PPA in
nitrogen
in
239, 257
were observed
600
(*C)
thermal analysis curves
peaks
500
400
TwnparetunB
The DSC
0.0
JmJL.
JLmtm
[19].
nitrogen are
and
495
in the DSC. The
27
illustrated in Figure 1.10
C)
and endothermic peaks
exothermic peaks at
239
and
both irreversible
257C
are
curve.
The
ascribed
mass
to volatilization
interpretation is
is
initial
slow
loss
of solvent
strengthened
onset
by
a mass
by the
temperature
below 250 C is
changes
of
a change
from light
This
appearance.
the
loss
molecules
to
The
be
to
attributed
molecular
mass
scission
the
peak at
495
transition
about
C in
products,
and
can
be
and
at
the
239 C
257 C
the
at
are
which
is
the
by
polymer.
28
to the
C,
This
which
DSC is
not
to the
change observed
color of
a
the PPA
glasslike
and
257 C may be due to
of a
decomposition process,
between 250
followed
and
DSC
500 C
by aromatization
in this temperature
slow
originally
corresponds
takes on
of
range.
can
low
The
as an endothermic peak at
exothermic peak at
attributed
on
polymer
239
volatile
observed
141
The
occurred
TGA
matrix.
polymer.
the initiation
60% that
was
polymer
peak shoulder at
(decomposition)
superimposed on
the DSC
from 60-215 C
endothermic peak at
exothermic peak
brown
yellow
loss
was observed on
loss step in the TGA. The only
aromatic products
339 C, partially
the
physical properties of
polymer chain scission
volatilization of
about
major mass
loss
trapped in the
that the exothermic peaks
crystallization or a solid state
respectively.
the
The
mass
observed
occurrence of
major mass
yellow
means
while
in the
5%
of about
consistent with a volatilization process.
accompanied
A two-step
and significant.
257 C. The
decomposition
of
exothermic
the remaining
DSC (
80
TG(
)
-
)
DTG(-
-
-|100
60
-
80
5
4
P
f-
60
-
-r-
3
v>
a
2
2
20
40
Q
0
-
i
i
i
i
i
300
200
100
Temperature
Figure 1.11. Thermal
The DSC
is
on
appear at
C
on
mass
curves
and above
of about
second
can
be
step in
attributed
a combination of all
loss)
in
shows a
sharp
PPA in
oxygen are
scales
mass
illustrated in Figure 1.11 [19]. The DSC
from that in Figure 1.10.
second
nitrogen
600
oxygen.
512C. Their distinct
The
500
400
(C)
6% from 60-215 C is
polymer matrix.
to the
DSC
probably
TGA
and
223, 373 C
trapped in the
similar
analysis curves of
significantly different
TGA. The first
is
1
-
-20
curve
-
20
mass
loss
exothermic peaks
steps are observed
not so complex.
The
to oxidation, cross-linking and
60%
mass
loss
exothermic peak at
373
at about
decomposition
three. The third step observed around 498
loss
rate and corresponds
29
in the
again associated with solvent molecules
step from 242-427 C
but
Only
or most
C (ca. 70%
to the onset temperature
of
the
exothermic peak above
oxidation and
512 C. The
decomposition
In the Figures
1.10
entire
remaining
polymer
is
converted
to gaseous
processes.
and
1.11,
the
DTG
considerations.
30
curves
were
not
important
for
our
1.8
Doping
To
PPA
of
improve
the
polyphenylacetylene.
of great
electric
Several
and
doping. For heterogeneous
mixed and ground
sticky
the
doping
generally
described [21-23],
procedures are
dope
to
needs
one
and
the
I2 dopant is
interest.
V. Shivsubramaniam
doping
conductivity,
had taken
and
it is hard to
polymer and
under reduced
doping
together in
place.
G. Sundararajan
If in
pressure, the doped
an easier
The
dry
mixture
by
THF After the
the
make
weight
turned black
iodine is high, the
polymer was recovered as
way to
amounts
homogeneous medium,
a
dissolved in
found
appropriate
concentration of
obtain pellets.
were
iodine,
with
a mortar and pestle.
And, if the
dopant
[21]
mixture
the
were
when
the
becomes
weighed amounts of
solvent was evaporated
residue
for conductivity
testing.
Besides the
make
method
described from above, Furlani
the doping. Powdered
BF3, H2O, HC1, for
about
polymers were exposed
twelve hours in
a sealed
31
et
al.[22]
used another method
to dopant vapors, like
flask.
to
HNO3, NH3,
1.9 Composition
Carbon
done
to
nanotubes
make
carbon-based
strength and
From
effect,
irradiation
There
about
30
with
are
and
Xu's
protect
PPA
two types of
60 A
1
nm
and
to 1
/mi.
length is
as
carbon
nanotubes,
see
high
times. Much
carbon
properties
from
as
as
has been
These
nanotubes.
such
exhibit a
research
high
new
mechanical
conductivity [24-26].
strong
photodegradation
photostabilization
harsh laser
under
10 J/cm2.
nanotubes, single-walled carbon nanotubes and
Figure 1.12.
nanotube, the tube diameter is about 8
For the
about
the
the nanotubes
chains
incident fluoresence
recent
chirality-dependent electrical
[24],
research
with
exceptional
possess
the
interest in
polymers
single-walled carbon
about
-
of
of
flexibility diameter and
multi-walled carbon
length is
Carbon Nanotubes
and
have been
nanomaterials
can
For the
PPA
composites
Tang
and
of
1
nm
multi-walled carbon
to 1 /xm.
32
-
15
A
and
nanotubes, its diameter is
Source:
Rensselear Polytechnic Institute
Troy, NY
(A)
Source:
Carbon Nanotechnologies Inc.
Houston, TX
Figure 1.12. (A). Single-walled
nanotubes
carbon nanotubes
(MWCNT).
33
(SWCNT)
(B). Multi-walled
carbon
1.10 Basic Research Plan
In
(PHX)
research, the
our
are made.
of interest
Especially polyphenylacetylene,
because
Four types
1 -hexyne.
of
triethylaluminum
bisimino
more
good
Shirakawa
photoconductivity
catalysts
were
the
other
is
used
is
a
recently [27]. Methylaluminoxane
a
more
[(InfhPyrFeCy
(MAO) is
titanium
of
dichloride [En(Ind)2ZrCl2]. A
iron dichloride
acetylene
and polyhexyne
derivative, has been
polymerization of phenylacetylene and
comprised
one
(PPA)
and electroconductivity.
for the
selected;
(CpaZrCy,
zirconium
pyridine
catalyst,
typical
a
[Ti(OC4Hg)4 / A1(C2H5)3], is
biscyclopentadienyl
bisindenyl
its
of catalysts were selected
The
metallocene
polymerization of polyphenylacetylene
as
a
reference
traditional
modern
tetra(-butoxide)
catalyst.
basic
chiral
chosen,
Two
metallocene,
catalyst,
non-metallocene single-site
was also
and
which was
ethylene
catalyst,
developed
to be used as cocatalyst for these three
single site catalysts.
After the polymerization,
undertaken.
that the
If time
are
to be
important
characterizations of
These include IR spectra, NMR spectra,
doping
was
some
of the polyphenylacetylene
available,
several runs
for the
is to be
the polymers are to be
DSC, TGA, GPC
conducted
to
and others.
improve its
After
conductivity.
composites of polymer and carbon nanotubes
made.
34
2. Experimental
2.1 Apparatus Preparation
Argon is
must
be
dry
then flushed
or oxygen
used as
inert
enough and
with argon
in the
gas
during
then be
all of
prepared
repeating the
in
cycle
apparatus and reactors.
the
experiments.
argon.
They
three times to
The
Figure 2.1.
35
system of
The
apparatus and reactors
are all subjected
ensure
to
vacuum and
that there is no
preparing the flask is
moisture
shown
in
oil
BusaiEft
'
Ann
Figure 2.1. ACE Burlitch
no-air system
for
work under
36
inert
atmosphere.
trap
2.2 Reagent Preparations
2.2.1 Structure
During
the
of
Catalysts
experiments,
They
polymerization.
are
four types
listed in Table 2.1
of
and
catalysts
systems
their structures
were
are shown
used
in
the
in Figure 2.2.
Table 2.1. Catalysts System in Experiments.
Catalyst
Category
Shirakawa
catalyst
Titanium tetra(n-butoxide)
[Ti(OC4H9)4]
Cocatalyst
A1(C2H5)3
Biscyclopentadienyl
Basic
MAO
metallocene catalyst
[Cp2ZrCl2]
Rac-ethylene-bisindenyl Zirconium
New
dichloride
metallocene catalyst
MAO
[En(Ind)2ZrCl2]
2,6-Diacetylpyridine
Late transition
metal catalyst
bis(2,4,6-trimethyl-anil) iron dichloride
[(Im)2PyrFeCl2]
37
MAO
lino
OBu
CI
ZrC
BuO"
OBu
CI
Biscyclopentadienyl
Titanium tetra(n-butoxide)
Rac-ethylene-bisindenyl Zirconium dichloride
2,6-Diacetylpyridine
bis(2,4,6-trimethyl-anil)
iron dichloride
CH3
A1(C2H5)3
-Al
Methylaluminoxane
Triethylaluminum
Figure 2.2. Structures
o-
of catalysts and cocatalysts used
38
in the
polymerization.
2.2.2 Synthesis
Iron Catalyst
of
The late transition
to synthesize the
form the final
metal catalyst
2,6-bis(imino)
is
pyridyl
synthesized
ligand,
by
Gibson's
method.
then let the ligand
The first step is
react with
the
FeCl2
to
catalyst.
The ligand had been already
made
by
Xuan Mai [30]. The
reaction scheme
is
shown
in Figure 2.3.
H,C
CH,
/ \
1.
ROH
+
2. 80
H3C
C
-CH,
NH,
Figure 2.3. Reaction
The
following
carried out also
butanol is
flask is
schematic
step, the
in this
prepared
prepared
in
in
work.
for the
synthesis of
complexation of
The
reaction
molecular sieve
is
2,6-bis(imino)
the iron
shown
with a
39
chloride with
in Figure 2.4. In
for 2 hours to
argon and connected
( II )
pyridyl
dry
enough.
thermometer
a
100
ligand
the
ligand
ml
flask,
was
50ml
A three-neck 500ml
and a reflux condenser.
Then
0.191g
80C in
(1
mmol)
.51
an oil
bath. After
mmol) ligand
was added
solution turned
let it
cool
time, 100
room
diethyl
Figure 2.4. Reaction
After stirring
concentrate
overnight
of
it for 45
catalyst and a
about one
little
30
and
by
filter
butanol
ml
hour,
all
temperature
and
the black
min
-
for the
another
then stirring was
synthesis of
catalyst solution
iron
for drying. Finally,
to isolate the
about
0.7g
(=
The
to
40
the
was stopped
At
to
same
dry overnight.
catalyst.
was subjected
ether was added
to vacuum to
to precipitate the
product was subjected
87 % yield) dark blue
got.
heating
(1.51
color of
continued overnight.
overnight, it
solid.
0.598g
FeCl2. The
contained
1 5 minutes, the
1 hour. Then 30ml diethyl
was used
and stirred at
the solid dissolved completely,
ether was prepared over molecular sieve
schematic
in this flask
were mixed
little to the flask
to dark blue. After stirring
down to
ml
FeCl2
solid
iron
to vacuum
catalyst was
2.2.3 Other Catalysts
All
the other catalysts are
of
Methylaluminoxane is
was used
in
almost pure
2.2.4 Preparations
which
heated
at
subjected
is
80 "C
to
10
from the Aldrich Chemical Co.
purchased
as
wt% solution
in toluene from Witco. Triethylalumium
form (93%).
of Monomers
Phenylacetylene
flask,
used as
used
(98%)
prepared
in
overnight.
or
argon.
5g
Then,
the
vacuum
reduced
1 -hexyne
on
(96%)
calcium
hydride
monomer was
a
cold
introduced into
was
(CaH2)
distilled
condensing
a
three-neck 1 L
to the flask
and
over calcium
hydride
and
Thus,
and
was added
surface.
pure
dried
monomers were obtained.
2.2.5 Preparation
Toluene
first
of
Solvent
was used as polymerization solvent.
refluxed overnight over metal sodium and
toluene
requires about
toluene
was
distilled
3g
metal sodium and
and collected
in
a
In
a
2 L three-neck
benzophenone
5g benzophenone
1 L flask in
in Figure 2.5.
41
argon.
at
60 C.
flask,
toluene was
Normally
600
ml
to be dried overnight. Then
The distillation
set
up is
shown
4
Shorter
DisuUanor
Path
Kem-Kiamp
PTFE
Sleevi
*3G,Mfks4)
kiceivt*
Ftett
Figure 2.5. Toluene distillation
Here
argon
is
set-up.
all reagents and solvents were
used as
inert
handled
gas.
42
by
using Schlenk-tube techniques
and
2.3 Polymerization Procedures
2.3.1 Polymerizations in the Small Reactor
Firstly
and
the
small reactor was prepared.
then flushed
with argon at
reactor was cooled
down to 25
in the
The
experiments.
C,
reactor set
<*
*
was
70 C. This step
which
up is
reactant.
Ar/Vacuum
It
|
1
1
heated
was repeated
shown
in Figure 2.6.
inlet
?
i
connect
3
magnetic
Figure 2.6. The
to hood
Thermometer
stirring bar
inlet
stirring device
small reactor set-up.
43
for 1 5
three times
is the typical temperature for the
*-
bath
under vacuum
and
minutes
then the
polymerization
Catalyst
catalyst.
In
was added
To
solution
case of
was
the Shirakawa
directly. Different
the
prepare
catalyst
firstly the
and
catalyst are
listed in the table in the
solid
This
cocatalyst.
depending
other
following
the
catalyst.
aged
for
some
The
monomer concentration was
at
was added
and
followed
by
time. The aging time
1 M
experiments.
of
the
Discussion. The
runs.
hour. After that the
kept
the
concentrations
Results
section on
metal catalyst
toluene was transferred to
For Shirakawa catalyst, aging took
an
during
metallocene
one
the
was
hour,
catalyst and
and
monomer was
(phenylacetylene, 5.55
different
also
for
all of
introduced.
ml;
1-hexyne,
ml).
The
using
the
solution was
added.
for different
toluene
solvent
three catalysts, aging lasted half
Here the
5.75
on
the
appropriate amount
catalyst powder was
cocatalyst concentration was also changed
firstly
flask for the
ml
iron catalyst, the transition
catalyst or
the reactor,
In the reactor,
100
separate
a
catalyst concentrations were applied
solution,
then the
in
prepared
polymerization was run
aluminum
foil. The
polymerization
orange-purple
HC1, if there
too
Finally
changed
solution
the
from the
from
and
dried in
product was
dark
solution.
much cocatalyst residue
solid, and then filtered
under
polymerization was stopped
solid precipated
was
for 24 hours
stirring
by
to
The
in the
and protection
adding
yellow
methanol.
or
from light
The
orange
color of
and
product was washed with
polymer product
appearing
some
dilute
as white
vacuum.
transferred to a small vial with argon and weighed to give
44
the yield. The vial
was saved
2.3.2 Polymerizations in
Finally
shown
in
a
argon and protected with aluminum
Large Reactor
some selected runs were carried out
in Figure 2.7. The iron-based
products.
The
then cooling
reactor was prepared
down to the desired
were same with
the
film from light.
small reactor.
in large Buchi
catalyst was used
by
purging
reaction
for these
vacuum/argon
reactor.
runs
to
The
set
up is
obtain more good
three times
at
70 C
and
temperature. The polymerization procedures
The difference
45
was
how to handle the
set-up.
Drive Motor
Magnet
Thermometer
/>>-.
U Vacuum /Argon Port
Thermometer
Sleeve
{j
Ethylene Port
Inner Reaction
Sleeve
Outer Vessei
Mixing
Figure 2.7. Large Buchi
reactor set-up.
46
Propeller
2.4
Doping
of
Polyphenylacetylene
To increase its conductivity, the
doping. Of several
it
was
readily
Firstly
methods
available and
4.42 g iodine
dissolved quickly
and
for the
doping
of
PPA, iodine
was
was chosen as
subjected
to
dopant, because
inexpensive.
in 220
was placed
the
polyphenylacetylene
prepared
color of solution
ml
degassed CCU
became
purple.
The
under argon.
The iodine
solution was
kept
being
stirred overnight.
The
(ca. 8
sample
CCU
polymer sample was
mm
in diameter
the
were poured on
to dark
the
and
of
prepared
0.5
dish
mm
in KBr
thick)
pellet
and
press,
then the disk-shaped
was placed on a glass
pellet made of
PPA. The
color of
dish. 5
ml
I2 in
the sample turned
purple/black.
The sample, that
parts.
top
first
It
was
was not possible
sample
(at least 2
dried
with
argon, became very fragile
to obtain a conductivity
mm).
47
because there
and
broke up in
was not enough
smaller
depth
of
2.5 Composites
In
some
produce
added.
then
the Polymer
The
with
composites.
In the
Carbon Nanotubes
carbon
experiments, multi-walled
PPA/nanotube
small
carbon nanotube solution was shaken
nanotubes
(MWCNT)
reactor, first MWCNT
in
an ultrasonic
were
and
bath for 15
used
toluene
to
were
minutes and
stirred overnight.
Secondly,
The
of
color of
added
the
into the
protected
the
catalyst and cocatalyst were
catalyst solution was
reactor.
by aluminum
The
reaction
dark
time
introduced into
now.
After aging half
was about
film from light.
48
carbon nanotube solution.
48 hours
an
and
hour,
the
monomer was
reactor was well
2.6 Characterization
2.6.1 Infrared
of
Spectroscopy
Infrared spectroscopy
isomers.
trans
IR
The IR
was used
spectra
spectrophotometer on
plate.
Polymers
were
to determine the
thin films
obtained
be
recorded
spectra could
with
recorded
from
2.6.2 NMR
Proton
temperature,
Series
3000
FTS
on
KBr
polymer solid powder.
The
in CDCI3
using
ratio of cis and
4000 to 500
by
deposition
.
Spectroscopy
nuclear
on a
magnetic
Bruker 300
chemical shifts were recorded
standard.
solutions
the
Biorad
FTIR
a
directly by
samples were scanned over a wavelength range
structure and
The
resonance
(1 H-NMR)
spectrometer.
in
The
ppm units with
sample solutions were about
2.5%
spectra
were
samples were
and
the
at
room
dissolved in CDCI3. The
tetramethylsilane
(wt/v)
recorded,
(TMS)
as an
internal
spectra were recorded at
300 MHz.
2.6.3 Thermo Gravimetric Analysis
TGA
with
measurements
increasing
thermal
stability.
are used
(TGA)
to determine
temperature and provide
The TGA
weight percent changes of
information
curves were obtained
49
by
about
using
a
the sample
composition analysis and
TA Instrument
model
TGA
2050. The
nitrogen gas.
90
For
cm3/min and
placed
in
some
runs,
the airflow
a platinum pan
2.6.4 Differential
DSC is
temperature,
DSC
heated from 25 C to 1000 C
polymers were
a
very
air was used
rate
for the
is 25
for
comparison.
cm3/min.
The
at a rate of
The
C/min
10
nitrogen gas
flow
under
rate
1 5mg
sample powder of about
is
was
analysis.
Scanning Calorimetry (DSC)
method
useful
crystallization
curve were obtained.
for the
temperature
characterization of polymers.
and other
The TA Instruments
thermal data
model
of
DSC 2010
the
The melting
polymer
was used
to
from the
analyze
the
polymers.
About 10 mg
aluminum
the
pan,
of
the DSC
10 C /
in
powder
but
without
any
sample
the DSC instrument. A liquid
chamber.
min.
form
was
weighed
which was sealed with an aluminum cover.
same procedure
furnace
sample
The
The DSC
The GPC is
used
pan.
nitrogen
of
80
placed
in
a
hermetic
pans were placed
into the
ml/min was maintained
cooling/heating temperature
in the temperature
by
reference pan was made
Then the
flow
runs were carried out at
polymer was analyzed
2.6.5 Gel Permeation
in the
A
and
range
in
rate at
from 25 C to 600 C.
Chromatography (GPC)
to determine the number-average molecular weight
50
(Mn)
of
the
polymer.
It is
standards.
The
HP 1090 instrument
recorded on a modified
sample concentration was
4.5
calibrated with polystyrene
mg/ml
2.6.6 UV-Vis Measurement
The
UV- Visible
instrument
by
using
absorption
spectra were
quartz cuvette.
The
recorded
sample of
PPA
on
SHftMADZU UVVIS 2410
made
by iron-based
catalyst was
10"
prepared
The
by dissolving in CHCI3
CHCI3
solution was
wavelength range
2.6.7
Solubility
The two
were
briefly
pure
from 1 90
the
scanned as
nm
to 800
baseline
and
the sample is 5
x
mg/ml.
then followed sample solution at
Studies
PPA
samples produced
dissolved in the
From the
concentration of
nm.
stirred with chloroform and
samples were
already
first
and
then let
reactor with
stand overnight.
the iron-based catalyst
In both cases,
all of
the
solvent.
polymerization
precipitated
in the large
runs, it
in the toluene
was shown
that
some of
used as polymerization
methanol all of the polymers were precipitated.
51
the formed PPA were
solvent.
When treated
with
2.6.8
Electroconductivity
About 20 mg
pellet press
in
polyphenylacetylene sample was pressed
a glove
box. The
of each sample was about
by
using
initially
[29]. The latter
the
a
0.5
four-point
probe
instrument
in the
case of
the contacts became irrelevant
52
by
using
a
KBr
clean, fresh and homogenous. The thickness
mm and radius about
was more useful
resistance of
sample was
to a film
8
mm.
[28],
The conductivity
and a two-point probe
the base polymer, the
at
was obtained
its low
undoped
conductivity.
instrument
PPA,
since
3. Results
and
Discussion
3.1 Polymerizations
The
polymerization
conditions
Table 3.1. Polymerizations
include different
cases.
were run at
portions of catalyst
Later, how
the
different
and polymer yields of
relatively low
residues,
pure polymer yield was
runs
are
catalyst concentrations.
listed in
The
which was not always removable
determined
by
using
additional
yields
in
all
TGA data
was shown.
Lower
to use to
catalyst concentration
measure
the
concentrations were
with
catalyst
to cocatalyst,
For
most of
with some
potential of
kept low, to
the resulting
residue
being
the
than
and
the
with
new single-site catalysts.
prevent
polymer.
the formation
Many
color
due to
be
of
was
the
intended
cocatalyst
amounts of aluminum
depend
on
the
ratio
of
be lowered.
obtained.
Most
products were orange/purple
aluminum salt residue.
53
Similarly
high
polymer properties
therefore both needed to
runs polymer could
lighter in
the original Shirakawa catalyst
Table 3.1. Polymer Yield
and
Catalyst Concentration.
Product
Monomer
Cocatalyst
Catalyst
Yield
type
Cone.
Cone.
Name
Name
(g)
(M)
(M)
Solid/
1-Hexyne
Ti(OC4H9)4
0.01
A1(C2H5)3
1.0
A1(C2H5)3
1.0
5.058
Yellowish
Solid/
Phenylacetylene
Ti(OC4H9)4
0.01
4.721
Yellowish
Solid/
Phenylacetylene
Cp2ZrCl2
lx
10"5
MAO
0.3
0.290
Orange
Oily/
1-Hexyne
Cp2ZrCl2
lx
10"5
MAO
0.3
Orange
Phenylacetylene
Cp2ZrCl2
lx
10"4
Solid/
MAO
0.3
0.132
Orange
Phenylacetylene
En(Ind)2ZrCl2
lx
10"4
Solid/
MAO
0.3
0.611
Yellow
Phenylacetylene
En(Ind)2ZrCl2
lx
10"3
Solid/
MAO
0.3
0.207
Orange
1-Hexyne
En(Ind)2ZrCl2
lx
10'3
Oily/
MAO
0.3
Orange
Phenylacetylene
(Im)2PyrFeCl2
lx
10"3
Solid/
MAO
0.073
0.145
Purple
1-Hexyne
(Im)2PyrFeCl2
lx
Solid/
10"3
MAO
0.073
0.053
Purple
54
For
25C
all of
and
To
these runs, the
running time is
monomer concentration
about
20 hours. Total
the efficiency
evaluate
of
is 1 M. The
reaction volume
the individual catalysts,
reaction
is 50
temperature is
ml.
one needs
to
establish
the
catalyst activities.
The
catalyst
activity
Catalyst activity
(mass
The
of polymer)
For example, the
catalyst concentration
mol;
reaction
/ (mole
activity is
polymer
is 1
10"3
x
time is 20
Iron
by equation
calculated
hr;
catalyst
of catalyst) x
(time)
(3)
g/mofhr.
yield
M,
so
is 0.145 g (PPA
the
made
mole of catalyst
is 1
then:
activity
=
catalyst activities are shown
10"5
0.145 /(5
=
The
3.
=
unit of catalyst
10"5
be
can
145
x
g/mol -hr
in Table 3.2.
55
x
20
)
from iron catalyst); the
10"3
x
M
x
50
ml
=
5
x
Table 3.2 Catalyst Activity, C/s-form Percent
and
Yield
of
Some Runs.
after
Catalyst
Cw-form
adjustment
activity
content
Yield
Product
Yield
Monomer
Catalyst
(g)
color
(g)
(g/mol-hr)
(%)
1-Hexyne
Ti(OC4H9)4
5.058
1.568
156.8
*
Yellowish
Phenylacetylene
Ti(OC4H9)4
4.721
2.502
250.2
84.85
Yellowish
Phenylacetylene
Cp2ZrCl2
0.132
*
1296.8
85.44
Orange
Phenylacetylene
En(Ind)2ZrCl2
0.207
0.197
197.0
85.49
Orange
Phenylacetylene
(Im)2PyrFeCl2
0.145
0.122
122.0
84.92
Purple
1-Hexyne
(Im)2PyrFeCl2
0.053
*
*
Purple
*Data
are not available
because
For polyphenylacetylene, the
The
cis-form
calculated
PPA
characteristic
by equation
1
little
amount of products.
cis-form content can
absorbance
peak
be determined from IR
is
spectra.
740cm"1
at
and
czs-content
is
.
%
From the IR
of the
53.0
spectra
cis
=
5.5
A740 /
10"z
-2
(5.5A740
in Figure 3., the A74o
%
cis
=
5.5
x
=
0.732 /
+
A760)
0.732; A760
[10"2
(5.5
x
=
(1)
0.719,
0.732
+
so,
0.719)]
84.85%
From the TGA curves, the
made
percent residue was obtained.
from Shirakawa catalyst, the
g, then the true
residue percent
yield of polymer product
is:
56
is 47%,
For
and
example the run of PPA
the polymer
yield
is 4.721
yield
=
=
4.721
x
47%
2.502 g
that is the data
catalyst
-4.721
after
activities,
the TGA curve adjustment. The TGA
cis-form percentages of the polymer and
of some of the runs are also
Evaluating
iron-based
single-site catalyst was
iron-based
catalysts are comparable
cis-form
of
the
polyphenylacetylene
polymerization
polymer can
the
all
be
temperature
made at
cw-form polymer
is
the yields
after
the
later. The
adjustment
listed in the Table3.2.
the activities and color
From the table,
curves are shown
of
the samples, the conclusion was made that the
better than the
to most
applied
of the
catalyst
metallocenes.
Shirakawa
The
activities
of
the
of more
of
the
catalyst.
led to the formation
than the trans-form. This is very probably due to the
being
relatively low. From the
higher temperature
produced.
57
ca.
literature,
150C. At temperature
the trans-form
of
25 C mainly
3.2 Composites
To
make
of
Polymer
polymer/nanotube
and
Carbon Nanotubes
composites,
amounts and the yields of the composites are
results,
also
the iron
of the
was
listed in the Table 3.3. To
some runs without carbon nanotubes are also shown
Table 3.3 Experimental Data
catalyst
Polymerizations
of
chosen.
The
compare
the
in Table 3.4.
Composites.
Catalyst
Yield
Monomer
MWCNT
[Fe]
[Al]
activity
(g)
(g/mol -hr)
1x10"
Phenylacetylene
30 mg
Phenylacetylene
60 mg
1x10
1-Hexyne
60 mg
1
Here the
monomer concentration
carbon nanotubes.
These
The
runs were
reaction
x
-3
10
is 2 M. The
temperature
handled in the
3
is 25 C
smaller reactor.
58
0.073
0.78
331.4
0.073
0.45
189.5
0.073
0.75
315.8
yield
and
is
obtained with
running time is
the amount of
about
48 hours.
Table 3.4 Polymerizations
x
with and without
Carbon Nanotubes
by Using
Iron Catalyst (]
-3-,
KPM)
Monomer
MWCNT
(Cone.)
Phenylacetylene (1
1-Hexyne (1
M)
M)
Yield
Catalyst activity
Running time
(g/mol-hr)
(hr)
(g)
0
0.12*
122.0
20
0
0.05
53.0
20
Phenylacetylene (2
M)
30 mg
0.78(0.68*)
331.4(283.4*)
48
Phenylacetylene (2
M)
60 mg
0.45
189.5
48
60 mg
0.75
315.8
48
1-Hexyne (2
*The
All
yield
of
nanotubes
nanotubes
M)
is
after
the TGA
curve adjustment
these runs were handled
did
not reduce
are
nanotubes were
in the
the
same
added, the
carbon nanotubes can
smaller reactor.
catalyst activity.
range
catalyst
result
in the
in
as
The
for the
From the Table 3.4, the
activities when
pure
polymer.
activity decreased. This
good product
=
30 / 680
59
But
when
=
4.4%
the
more
carbon
carbon
means a proper amount of
yield, for example, the
CNT,
MWCNT%
introducing
carbon
runs with
30 mg
The
PPA-MWCNT
PHX-MWCNT
adjusted
mostly
by
composite as
TGA
a's-form
composites
appeared
black-green
curve except one sample.
PPA-CNT
as
black-yellow
color powder.
From the IR
composite.
60
The
color
yield
spectra of
powder
shown
here is
and
not
this sample, it is also
3.3 Selected Runs in the Large Buchi Reactor
Table 3.5
shows the reaction experimental
reactor.
Based
catalyst
for these scaled-up
on
the results
of
the
runs
in the
data
and
smaller
the
result
in the large Buchi
reactor, the iron-based single-site
runs was chosen.
Table 3.5. Experimental Data
of Polymerizations
in Large Buchi Reactor.
Reaction
Running
Monomer*
[Fe] (M)
Product/yield
time
[Al] (M)
temperature
(g)
(hr)
(C)
Red
Phenylacetylene
1.0
xlO"3
0.073
solid/
25
48
1.10g
10"4
Phenylacetylene
2.5
x
Phenylacetylene
2.5
x
Phenylacetylene
1.0
Phenylacetylene
2.5
10"4
0.073
96
25
Red
0.073
48
65
Red/purple
oil
48
45
Red/purple
oil
48
55
Red/purple
oil
xlO"4
*
The
0.365
-4
xlO"4
0.073
monomer concentration
is 2.0 M for these
From the Table 3.4, the iron
the
reaction
what
the
catalyst
temperature was
catalyst
can
leads to
increased, only oily
concentration
concentration
catalyst
or
cocatalyst
influence
the
61
solid/
0.63
runs.
solid product at room
product could
concentration
polymer
yield.
temperature. If
be obtained,
is. At
same
Reducing
no matter
temperature,
the
catalyst
by four
concentration
times and
doubling
amount of polymer product was obtained.
with
very low
products
molecular weight.
had relatively low
From the IR
obtained:
NMR
the
the
The
spectra
and
TGA curve,
cw-form polymer content and
spectra were also used
purple
The GPC data
molecular weights
to determine the
104x 0.5/
16.66
These
results are given
62
proved
-2600
results
that
half the
the polymer
also
the solid
g/mol).
these two
about
TGA
cis-form content
(16.66x5.2)
in Table 3.6.
later
2300
about
product contains
yield after
At)
57.9 %
=
more
i.e. from Figure 3.10:
%cz5=104A58/(
oily
shown
(Mn
true
running time,
reaction
runs
were
curve adjustment.
by
using the
The
equation
2,
Table 3.6 Additional Results
of
PPA Made in Large Buchi Reactor.
Czs-form
Yield
Qs-form
Catalyst
after
Yield
Monomer
Catalyst
content
adjustment
content
activity
from
(g)
from IR
(g/mol -hr)
(g)
NMR
Phenylacetylene
(Im)2PyrFeCl2
1.10
1.10
76.36
56.7%
86.0%
Phenylacetylene
(Im)2PyrFeCl2
0.63
0.61
84.82
57.9%
85.6%
From the TGA curve, the
and
3.38%
room
respectively.
temperature,
It
catalyst residue
to
cis-form polyphenylacetylene was produced as shown
The
5.8ppm
identify the
spectra appear
to be
catalyst
because the
runs.
peak
separate
And
peaks of
spectra.
740
and
from IR
760
at
spectra.
cm"1
but it is
So here the data from the NMR
more reliable.
reaction
thesis [30]. Here the
overlap
from the NMR
activity decreased
then decrease along
It is 0.13%
means more pure polymer products were obtained.
For the IR spectra, it is difficult to
easier
is very low for these two
time
with
Rp
a
little
was extended.
the
(rate
reaction
compared
Usually
time,
see
of polymerization)
63
the
catalyst
Figure 3.1,
is
the
with
runs
activity
which
equivalent with
in
small
will
reactor,
increase
and
is from Xuan Mai's
the catalyst activity.
Comparison
of
the Rp for Metallocene
and
iron(lll)
catalysts.
o
E
in
6
5
Time
Figure 3.1. The changing
Therefore,
the longer
using the iron-based
constant over a
curve of catalyst
run
catalysts.
time may
For
7
activity
not
64
vs. reaction
actually
metallocene
long time.
10
11
12
(min)
result
catalysts,
time
[30].
in higher activities,
however,
when
the activity remains
3.4 Characterizations
3.4.1 Infrared Spectra
Some important IR
xie-pli
spectra are shown
in Figure 3.2-3.7.
1 -satlplaleOB 1 4base
738.836
800.863
1645.378
2871 594
2943.163
-20
297
1454 527
-7
-7.52
336
-21.310
-49.223
-69
441
Wavenumber
Figure 3.2. IR
spectra of
Here every
PHX
peak was
made with
labeled
by
two
Shirakawa
numbers.
catalyst.
The first
number
t transrnittance. Peaks at 2943 and 2871
stretching
of alkyl
group.
Three
peaks at
1645, 1454, 1373
stretching.
65
is
wavenumber and
are assigned
are assigned
to C-H
to C=C
ne-ppaD-sarip-alBlOi
S
2859 671
-1.500
1594.655
-2.007
909 313
14-37.626
2921 778
3037
853
-2
835
-2.532
-2.849
I <t94.056
-2.834
2 7fi2
755.046
-7.379
693.139
''
3000
3200
2B00
2600
2400
2200
i
2000
1800
1600
1400
1200
-9.680
....
1000
i
800
600
Wavenumbei
Figure 3.3. IR
spectra of
Compared
3050 cm"1,
695
with
which
the IR
are assigned
to 1450
to
made with
spectra of
is due to the
cm"1
cm"'
PPA
aromatic
bending
cm"1
are also
Shirakawa
PHX,
C-H
catalyst.
there is
one more peak appeared at about
stretching.
Two strong
vibrations of aromatic
from C=C
stretching.
66
peaks at
C-H. Three
755
peaks at
cm"1
and
from 1600
Figure 3.4. IR
PPA
spectra of
2-
made
by metallocene
catalyst.
xie-ppa10-purple{3)
1644 237
-8.969
740 506
3000
2800
2600
2400
2000
2200
1800
1600
1400
Wavenumber
Figure 3.5. IR
spectra of
PPA
made
by iron
catalyst
67
in
small reactor.
1200
-14.952
1000
800
600
Xie_Oave_ppa23flaakFeCI2
3054 242
1.915
887 123
1443 746
1488 276
690 449
3000
2800
2600
2400
2200
2000
1800
549
-10
339
-1692
749 822
3200
-2
-3.529
1600
1400
1200
-14
445
1000
800
600
Wavenumber
Figure 3.6. IR
These three
to 2850
range
750
PPA
spectra of
spectra
(Fig.
cm"1
are assigned
from 1600 to 1450
and
700
spectra proved
made
by iron
3.4-3.6)
of
catalyst
in large
PPA look very
to C-H stretching
reactor.
similar.
The
peaks at
of aromatic and alkyl group.
cm"1
are assigned
The
from 3050
peaks
to C=C stretching. The two peaks
in the
at about
cm"1
are
that the
characteristic
peaks
of cis-form
polymers obtained were
68
indeed
and
trans-form polymer.
polyphenylacetylene.
The
xie-ppa 1
7-CNT-sallplate(2)baseline
2924.769 97 927
3046.318 97 654
695.201
3000
2800
2600
2400
2000
2200
1800
1600
1400
1200
92.952
1000
800
600
Wavenumber
Figure 3.7. IR
The
IR
spectra of
spectrum
PPA-MWCNT
of
the
composite made
by iron
catalyst.
is
similar
with
composite
polyphenylacetylene.
69
also
the
spectra
of
3.4.2 NMR Spectra
The NMR
spectra of poly(l
-hexyne) and polyphenylacetylene are shown
in Figures
3.8-3.10.
A_uu''
10
cpm
'
Figure 3.8. H-NMR
The
peak at
peaks at
6.8
ppm
is
of PHX.
from 2.6
assigned
ppm
to
to 0.9
proton of
ppm are assigned
double bond.
70
to proton of alky! group. The
Figure 3.9.
'H-NMR of PPA made by metallocene
71
catalyst
in
small reactor.
X.e-S2j
.:&
scars
Oh'
H
a
Ui
---f: -.'.
A.7-
"lU.
Time
.5
ii
spec:
UK
6SS3
:ki:
617; 835
:.0941sC
;i( iii;s*4
rj.
"
5
f:"
3X H00J12
En
c
WI1>.
^
u=
5 JC
0
GB
PC
:.oc
a km
y-.z ". MlBK'.frl^
ex
20.CC
-i
3ic: o
"2?
-.
TI
.<
PPJCT
:-:zck
'
Figure 3.10. H-NMR
of PPA made
In these two spectra, there is
ppm,
to
which
by iron
a
catalyst
strong
in large Buchi
complex multiplet
aromatic proton and rrans-form alkene proton.
is
assigned
other peaks appear at
The
13
r).c
:30 nso:
:t
ppr.
assigned
orr
:
3
spectra show
to
cw-form alkene proton
ppm
to 1
that the
ppm are
because
polymers are
at around
There is
of the
impurity and
and
PHX.
7
ppm.
It is
a weak peak at
in PPA according to the
exactly PPA
72
reactor.
reference.
solvent.
5.8
The
,
3.4.3 TGA Curves
The important TGA
curves are shown
Sample: PHX-run5
Size'
20.3810 mg
in Figure 3.11-3.15.
File C:. \Xie\run5-Ti(O4H9)001
Operator: Xie Xiaohang
Run Date: 16-Oct-02 09.07
TGA
Comment Ti(04H9)
20
-T\
'
\
0
8378mg
(4
111%)
82 91 "C 19
26mg
19
en
4.050mg
(19 87%)
5
16
I
390 14C 15
14mg
15
0.9480mg
(4.652%)
,/740
300
200
100
400
500
Temperature
Figure 3.11. TGA
This
heating
curve of poly(l -hexyne)
curve shows
to 740
in
600
700
28C 14
are
step is the decomposition
two
steps
of alkyl
800
nitrogen.
for this
group
process
according to the
and solvent volatilization.
73
I
Universal V2 6D TA Instruments
(C)
that the decomposition process of PHX starts at the
C. There
15mg
beginning
curve.
The
of
The first
second
step is
caused
by
breaking
the
changed and
treated
high because this
which contain
of
the double bonds. After 740
as residue.
For this sample, the
polymer sample was not cleaned
C,
the
residue percent
by dilute
HC1
the polymer is
is
about
solution.
not
69%. It is
Other samples,
fewer residues, follow below.
Sample: PPA10-FeCI2
Size.
mass of
File: C:...\run10-PPa-FeCI2.001
Operator: Xie
TGA
15.5380 mg
Run Date: 4-Nov-02 15 55
120
109 44C
6 355%
100
(0.9874mg)
288 81C
80
g>
60
40-
20
Residue
7 865%
(1.222mg)
445 70"C
'
400
200
600
Temperature
Figure 3.12. TGA
curve
of
PPA
made
by
nitrogen.
74
800
(C)
metallocene
catalyst
1000
Universal V2 6D TA Ins
in
smaller reactor
in
Sample Run 22 FeCI2 Catppajlask
Size: 5.7430 mg
Method: tga dave
100 r
I
File:
in flask ppa 001
Operator: Dave&Xie
Run Date 5-Jun-03 13 43
...\Run22
TGA
-It
A
'"
7.275%
(0 4178mq)
v..
~"-,.V
"~~ -.
\
\
80-
\
\
\
\
\
\
\
\
60
\
'
88.58%
(5 087mg)
\
|
\
\
en
0)
40-
\
\
\
20-
Residue'
'
^'
0
'
i
^___
1
i
200
i
400
600
Temperature
Figure 3.13. TGA
curve
of
PPA
made
iron
by
.
0 1337%
(0 007680mg)
800
1000
Universal V2 6D TA In:
(C)
catalyst
in the large Buchi
reactor
in
nitrogen.
The
to
A two-step
mass
loss
was observed on
initial
mass
loss
of about
slow
7%
volatilization of solvent molecules
about
85-90% that
scission
occurred
TGA
observed
curve of polyphenylacetylene samples.
from 50-200 C
was
originally
ascribed
trapped in the polymer matrix. The major mass loss
between 200
(decomposition) followed by
and
500 C
aromatization
75
can
of
be
attributed to polymer chain
low
molecular mass
scission
products,
which are volatile
for these two
shown
from the
in this temperature
samples.
polymer made
by iron
catalyst.
more
than 1 g products
it
were obtained
several
fewer
are
for
dry
enough.
most of
the
catalyst residues
cocatalyst was
Of course the best way to
the polymer several times and let it
wash
There
This is because the MAO
wash
difficult to
range.
During
in
runs
easily
removed
get pure polymer
is to
the experiments, only no
small
reactor, so it is
more
times.
Sample: PPA17-CNT-FeCI2
7 1610 mg
Size
Method. Ramp
File PPa17-CNT-FeCI2-N2-12.17
TGA
Operator Xie
Run Date. 17-Dec-02 16:10
120
100
10.24%
(0.7331 mg)
80
52 75%
(3 778mg)
J=
60-
40
*"--
w
--^
19.02%
(1.362mg)
20
-Residue:
17.30%
(1.239mg)
200
600
400
Temperature
Figure 3.14. TGA
curve of PPA-CNT composite
76
in
(C)
nitrogen.
800
1000
Universal V2 6D TA I
120
PPa17-CNT-FeCI2-air.001
PPa 1 7-CNT-FeCI2-N2-1 2. 1 7
100-
80
g>
60
40
20
200
600
400
Temperature
Figure 3.15. Compared TGA
The decomposition
PPA
sample
due to the
until
900 C
means
than the
polymer
uniform and
then
carbon nanotubes.
nitrogen.
From the
air and
in
nitrogen.
The
mass
loss
of sample
composite of polymer with carbon nanotubes
itself because that the
increase its
stability.
Figure 3.15
figure,
in
the PPA-CNT composite is more complex than the
combined carbon nanotubes.
that the
the
1000
Universal V2.6D TA In
curves of PPA-CNT composite
process of
800
(C)
shows
carbon
The 1 7%
the
composite
nanotubes
residue
compared
TGA
running in the
77
is
air
can
let the
is
is
changed
more stable
polymer more
composed of cocatalyst and
curves of samples
decomposed
earlier
in
air and
than in the
nitrogen.
About 4%
because the
residue
difference is due to the
carbon react with oxygen and
form
carbon
nanotubes
in the
sample
gaseous products.
3.4.4 DSC Curves
Some
representative
DSC
curves are shown
Sample: run12-sol
Size: 1.0100 mg
Method: Ramp
in Figures 3.16-3.18.
File:
Operator Matt
Run Date: 29-Mar-03 12:57
...\PPA-FeCI2run12-sol.002
DSC
40
162X0)
V432.96-C
429.05'C
Figure 3.16. DSC
The
300
200
100
Temperature
ExoUp
curve of
exothermic
PPA made
peak
at
375
by iron
500
catalyst.
C may be due
78
600
Universal V2.6D TA Instalments
(C)
to
crystallization
or
molecular
rearrangement.
the
aromatic
about
products.
decomposition
Sample:
At
of
432
The
C,
there is an
endothermic peak
exothermic peak at
the remaining
can
be
DSC
200
150
Figure 3.17. DSC
to the
slow
File: C:...\phx-cnt-20-FeCI2.001
Operator: Xie&Dave
Run Date: 14-Jan-03 15:02
phx-cnt-20-FeCI2
Up
attributed
polymer.
10.6800 mg
Size
Method: Ramp
Exo
550 C
that is the volatilization of
Temperature (C)
curve of PHX-CNT composite.
79
250
350
400
Universal V2.6DTA lr
Sample. ppa19-CNT-FeCI2
Size: 5.4500 mg
Method:
Ramp
150
Exo
Up
For the DSC
exothermic
initiation
of a
200
Temperature
Figure 3.18. DSC
an
File: C:...\PPA19-CNT-FeCI2 002
Operator: Xie&Dave
Run Date: 14-Jan-03 11:56
DSC
250
300
350
400
Universal V2 6D TA Ir
(C)
curve of PPA-CNT composite.
(Fig.
curve of poly(l-hexyne)-carbon nanotubes composite
peak
at
about
decomposition
149 C
process.
was
No
observed.
This
could
other peaks are observed
be
3.17), only
attributed to the
because
of
the
long
alkyl pendant group.
For the DSC
the
curve of polyphenylacetylene-carbon nanotubes composite
exothermic peaks at
160, 239
and
248 C may be due to
80
cis
to trans
(Fig. 3.18),
isomerization,
a
solid
state
volatilization of
about
initiation
transition and the
decomposition process,
the aromatic products is observed on DSC as
350 C. The
decomposition
of a
of
exothermic peak starts at
the remaining
400 C
on
DSC
catalyst
is
shown
can
The
respectively.
an endothermic peak at
be
attributed
to the
slow
polymer.
3.4.5 GPC Analysis
GPC
curve of PPA made
by iron-based
0.5
I
in Figure 3.19.
I'
\
"U
I
0.4
0.3
en
o
r
-2-4
0.1
=
0.0
iin rTiii
i
lie2
i i mini
i i i hum
i i iiiitii
i i m miii
i i mini
i i iiiiii
he6
Ue7
lie4
Ue5
'le3
Molar
Figure 3.19. GPC
GPC
curve of
i
'le8
PPA made
analysis can give us
the
by
mass
iron-based
i i iiiiii
I i mini
Ne9
ttt
'le10
[D]
catalyst.
molecular weight of
the
polymer.
From the
data,
the
number average molecular weight
weight
and
(Mw) is
-.5
10
,r,7
-10
g/mol.
(Mn) is
The
2600
number average molecular weight
the polydispersity is relatively high because that the
with
and weight average molecular
g/mol
catalyst was
is relatively low
different
compared
traditional catalyst.
3.4.6 UV-Vis Measurement
The UV-Vis
spectra of polyphenylacetylene made
by
iron-based
catalyst
is
shown
in
Figure 3.20.
5.296
4.000-
2.000
-
0.000-
-0.446
400.00
190.00
Figure 3.20. UV-Vis
absorptionspectra
of PPA
82
in CHC13.
600.00
700.00
The
spectra
indicate the
nm, which is due to the
3.4.7
Solubility
dissolve in
tested
of polymer
with
be established,
Therefore,
of
samples
by dissolving
absolute chloroform.
isomer. Together
can
transition
200
-220
the double bond.
Studies
The solubility
reactor was
7T-/T*
characteristic maximum absorption peak at about
see
the
made
by
iron-based
in large Buchi
catalyst
them in chloroform overnight. The samples did
This
means
the NMR studies the
that the PPA did
mass
distribute
not contain
of
the four
any
totally
cz's-cisoidal
possible
isomers
Table 3.7.
iron-based
catalyst
could
produce
all
cw-transoidal
form
polyphenylacetylene.
Table 3.7. Mole Percent Distribution
Cw-form
57.3% (]H-NMR)
Czs-transoidal
100%
(by solubility study)
G's-cisoidal
0%
of Four
(by solubility study)
Isomers
of PPA.
Trans- form
42.1%
( H-NMR)
7ras-transoidal
n.d.
Trans -cisoi&al
n.d.
3.4.8
Conductivity
The doped polyphenylacetylene
parts.
A conductivity
because there
became very fragile
sample
four-point
measurement with the
was not enough
depth
of
the
sample.
Thickness
P
=
of
2.1
Then two-point
2.1
=
2.3x
Q
x
1010
Conductivity
Here Siemens
=
is
exposed
testing,
and
itself is already
4.3
-
1/ Q
=1.1
is
10"12
about
to
S/cm:
mm, so,
10""
x
sample
oxidized
Siemens/cm
.
similar with
to light and
then
probe were used
cm
1/ p
It is very low but
to obtain
xO.ll cm
Q
=
which
smaller
Q
the Sample
10"
=
10n
x
broke up in
probe was not possible
test the conductivity of undoped polyphenylacetylene sample,
Resistance
and
oxygen
is
for
the
a
oxidized.
reference
long
time
Another
during the process
data [15]. One
during
84
is that the
sample
the preparation of the pellet and
possible reason
of cleaning,
reason
is that the
transferring
polymer sample
and saving.
4. Conclusions
All
the four different catalysts chosen for the polymerizations, were capable to
polyphenylacetylene, but only the Shirakawa
produce
for the
suitable
oily
of
synthesis of solid poly(l
product of poly(l
catalysts
led in
With the iron
obtained
Also, in
-hexyne).
several cases
catalyst a
because the iron
calculations
is yellowish,
better
a
key
and
the
role
by
iron
not perform as well
obtained, because the
The
The
analysis of
the IR
spectra and
poly(l -hexyne) agree well with
more of
the
cw-form of
the
'H
little
polymer made
in the
is
it is
an
metallocene
reason
by metallocene
orange-reddish.
The
single-site catalysts
be
the
ratio of
not shown
polymerizations and
in the
catalysts
metallocene
led to less
only oily
pure
products
very low.
NMR
spectra of polyphenylacetylene and
was produced
85
the
cocatalyst residue could
chemical structure of polyalkynes.
the PPA
only led to
is relatively high. Another
catalyst
were
molecular weight.
polymerizations and
molecular weight was
catalyst
is relatively low, is because the
At higher running temperatures, for both
product.
spectra,
the
catalyst activity.
polymer made
did
catalyst
during
iron
metallocene catalyst
polymer product with
iron
and
case of polyphenylacetylene
catalyst concentration
formula for the
catalysts altogether
were
has
to cocatalyst
the
The
to oily products due to low
cocatalyst concentration used with
catalyst
-hexyne).
catalyst
(57.3
%)
versus
From the NMR
the trans-form.
The
indicate that there is
spectra also
cyclization and/or
(TGA
and
DSC),
cross-linking
no
during
loss
the
the main decomposition
of unsaturation
polymerization.
due to
side reactions such as
According
to thermal analysis
200-500 C. These
process occurs at
The isomerization temperature is
were not pure and contained catalyst residue.
polymers
about
200
C.
With the iron based catalyst, the
polyphenylacetylene carbon nanotube composite
and poly(l-hexyne)-carbon nanotube composite were synthesized.
powdery
products.
higher than those
The
catalyst
is
more stable
carbon
synthesis of
is
about
IR
nanotubes.
conductivity.
than the
The TGA
polymer
2300-2600
g/mol.
of an
(Mn)
That is why
oily product,
the
composites
spectra
and
curve
shows
black
remarkably
NMR
be done for the
were
were
for the
spectra
composites
and
to
check
that the polymer-CNT
itself.
number average molecular weight
leads to the formation
<
for the
more characterizations used
structures or electric
composite
(Mn
activities
without
run, but
composite were
their
The
These
of polyphenylacetylene made
a slight
which
by iron
increase in temperature already
is very low
molecular weight polymer
2000g/mol).
of
the
The iodine doped PPA became very fragile
and
Solubility
cw-cisoidal
possible
to
studies
indicate that
most
polymer
is
cz's-transoidal
and
no
isomer is formed.
obtain a
conductivity
measurement
86
with
broke up in
smaller parts.
It
was not
the four-point probe, because there
was not enough
10"12
S/cm
depth
which
is
of
the
similar
sample.
to the
The
electric
reference
data.
87
conductivity
of undoped
PPA is
about
5. Future Research
1
.
Further
2. Change
3. Protect
optimize polymerizations
to increase
polymerization conditions
polymer samples more
catalyst activities.
to obtain higher
molecular weight.
effectively before conductivity testing.
6. References
1
.
2.
Chien,
W., Polyacetylene, Academic Press, Inc., Orlando, Florida, 1984
Herman F. Mark; Encyclopedia of Polymer Science
Wiley
3.
J. C.
& Sons,
Chandrasekhar,
3rd
edition,
P.,
and
Technology, Volume 1, John
January 2003
Conducting
Polymers,
Fundamentals
and
Applications,
Ashwin-Ushas Corp., Inc., Boston, 1999
4.
Chien,
J. C.
W.; Schen, M. A.; J. ofpolymer Science:
Polymer
Chemistry Edition,
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23,2447-2459(1985)
5.
Ito, T, Shirakawa, H,
6.
Chen, S-A.; Huang, C-F; Die Angewandte Makromolekulare Chemie, 150 (1987)
and
Ikeda, S.
J. Polym.
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171-178
7.
Naarmann, H.; Theophilou, N; Synthetic Metals, 22 (1987) 1-8
8.
Piaggio, P.; Bottero, C; Sommazzi, A.; Synthetic Metals, 28 (1989) D63
9.
Ilario, L. D.; Benni, P.; Cernia, E.; Eur. Polym. J. Vol. 23, No. 3 (1987) 213-216
10.
Wazeer, M.I.M., Tsonis, C.P., Polymer Communications, 27 (1996)
11.
Gal, Y.-S., Eur. Polym. J., 36,
12.
Due, S.; Petit,A., Macromol. Symp.,127, 77-87(1998)
13.
Shen, Z.,
14.
Douglas, W. E.,Appl. Organometal. Chem.,15, 23-26 (2001)
15.
Gruber, A.S., Boiteux, G, Polymer Bulletin 47, 529-537 (2002)
16.
Masuda,T., Hasegawa,K., Macromolecules, 7, 728 (1974)
and
Farona, M., J.
2059-2062
Polym. Sci.
(2000)
Chem., 22, 1009-1015(1984)
89
-
D68
17.
Simionescu, C. I.; Percec, V.; Prog. Polym. Sci. 8, 133 (1982)
18.
Leclere, M.; Prudhomme, R. E.;J. Polym. Sci. Polym. Phys. Ed. 23, 2031 (1985)
19.
Vosloo, H. C. M.; Luyt, A. S., J. of Thermal Analysis, 44(1995) 1261-1275
20.
Luyt, A. S. ; Vosloo, H. C. M.
21.
Shivsubramaniam, V; Sundararajan, G; J. ofMolecular Catalysis, 65 (1991) 205-210
22. Furlani,
23.
,
Thermochmica Acta 320
A.; Napoletano, C; Synthetic Metals, 21 (1987)
Wang, D.; Hasegawa, S.; Shimizu, M.; Synthetic
135-140
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337-342
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46,
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1, (January 1992):
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24.
Tang, B-Z; Xu, H.; Macromolecules, 32, (1999) 2569-2576
25.
Valerii, M. K.; In
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Micro- and
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