Controlled synthesis and functionalization of PEGylated methacrylates bearing cyclic carbonate pendant groups

Article abstract of DOI:10.1002/pola.23928

Homopolymer bearing cyclic carbonate (CC) group, ABA type triblock copolymers, and (AC)B(AC) type terpolymers with statistical arrangement of A and C monomers bearing side chain CC groups are reported here. Difunctional poly(ethylene glycol) macroinitiators (PEGMIs) were prepared from PEG of three different molecular weights. PEGMIs were subsequently used for the preparation of polymers bearing CC pendant groups from cyclic carbonate methacrylate (CCMA) under atom transfer radical polymerization to yield polymers with low polydispersity index. Homopolymer and ABA type triblock copolymers were obtained by polymerizing CCMA monomer and (AC)B(AC) type statistical terpolymers were obtained when methyl methacrylate was included as a comonomer. No polymer was obtained when styrene was used as comonomer. The cyclic carbonate groups were subjected to ring-opening reaction with monoamine to yield side chain hydroxyurethane polymers with increased solubility and diamines to yield crosslinked insoluble materials. Changes in wettability characteristics were studied by following the water contact angle of the polymers before and after ring-opening reaction involving the cyclic carbonate pendant group. The polymers which composed of electrolyte in the form of PEG and coordinating species in the form of pendant cyclic carbonate groups showed conductivity in the range of 2-5 × 10^-6 Scm^-1 at 23 °C after doping with lithium bis(trifluoromethane) sulfonimide as characterized by impedance spectroscopy.

Full text of DOI:10.1002/pola.23928

Controlled Synthesis and Functionalization of PEGylated Methacrylates
Bearing Cyclic Carbonate Pendant Groups
SATYASANKAR JANA, HAN YU, ANBANANDAM PARTHIBAN, CHRISTINA L. L. CHAI
Institute of Chemical and Engineering Sciences, Agency for Science, Technology and Research (A*STAR), 1, Pesek Road,
Jurong Island, Singapore 627833
Received 10 September 2009; accepted 7 January 2010
DOI: 10.1002/pola.23928
Published online in Wiley InterScience (www.interscience.wiley.com).
ABSTRACT: Homopolymer bearing cyclic carbonate (CC) group,
ABA type triblock copolymers, and (AC)B(AC) type terpoly-
mers with statistical arrangement of A and C monomers bear-
ing side chain CC groups are reported here. Difunctional
poly(ethylene glycol) macroinitiators (PEGMIs) were prepared
from PEG of three different molecular weights. PEGMIs were
subsequently used for the preparation of polymers bearing
CC pendant groups from cyclic carbonate methacrylate
chain hydroxyurethane polymers with increased solubility and
diamines to yield crosslinked insoluble materials. Changes in
wettability characteristics were studied by following the water
contact angle of the polymers before and after ring-opening
reaction involving the cyclic carbonate pendant group. The
polymers which composed of electrolyte in the form of PEG
and coordinating species in the form of pendant cyclic car-
bonate groups showed conductivity in the range of 2–5 ꢀ
ꢁ6
ꢁ1
ꢂ
(
CCMA) under atom transfer radical polymerization to yield
10 Scm at 23 C after doping with lithium bis(trifluorome-
thane)sulfonimide as characterized by impedance spectros-
copy. VC 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym
polymers with low polydispersity index. Homopolymer and
ABA type triblock copolymers were obtained by polymerizing
CCMA monomer and (AC)B(AC) type statistical terpolymers
were obtained when methyl methacrylate was included as a
comonomer. No polymer was obtained when styrene was
used as comonomer. The cyclic carbonate groups were sub-
jected to ring-opening reaction with monoamine to yield side
Chem 48: 1622–1632, 2010
KEYWORDS: ATRP; copolymerization; cyclic carbonate polymer;
functionalization of polymers; multifunctional polymer; statisti-
cal terpolymer; thermogravimetric analysis
INTRODUCTION Polymers bearing reactive functionalities
phobicity or hydrophilicity of the polymer by a suitable choice
of comonomer. Introducing polyethylene glycol moiety, which
is commonly referred to as PEGylation, into the polymer back-
bone is one of the strategies often used to improve the hydro-
philic nature of polymers. PEGylation makes the polymer
backbone hydrophilic, which is otherwise hydrophobic.
that are capable of chemical transformations upon usage are
1
useful as self-healing materials. Cyclic carbonates are one
such functional group, which, when present in a polymer
chain as a pendant group can be subjected to a variety of
transformations by reactions involving amines. Reaction of
cyclic carbonate with amines results in the formation of ure-
thane linkages along with primary and secondary alcoholic
units. Crosslinked products are obtained when diamines are
used in such ring-opening reactions. Because of such curing
possibilities, polymers bearing cyclic carbonate functionality
have enormous potential for coating and other related appli-
cations. They are also useful in energy storage devices like
Atom transfer radical polymerization (ATRP) offers the
advantage of making well-defined copolymers by means of
14,15
radical polymerization.
Polymers carrying CC pendant
groups with poly(ethylene glycol) (PEG) segments, block or
statistical copolymers of CC bearing vinyl monomers, and the
preparation of these polymers by a controlled polymerization
technique have not been reported so far. Hence, we designed
a synthetic strategy to prepare CC containing copolymers by
ATRP, which also carry polyethylene glycol units of varying
chain length. In this study, we report the first preparation of
controlled CC polymers using PEG-based macroinitiators to
tune the physical properties like solubility, wettability, and
film-forming properties and also to understand how these
properties are influenced by the ring-opening reactions
involving CC functionality.
þ
2–6
Li ion batteries.
Homopolymers bearing side chain CC functional groups have
2
,5–13
been reported previously by many researchers.
The CC
functionality introduces brittleness into the polymer chain
due to its high polarity and rigidity of the five-membered
7
cyclic carbonate moiety. Copolymer formation is an effective
strategy to overcome the problem of brittleness. Through
copolymerization, it is also possible to influence the hydro-
Additional Supporting Information may be found in the online version of this article. Correspondence to: A. Parthiban (E-mail: a_parthiban@ices.
a-star.edu.sg) or C. L. L. Chai (E-mail: Christina_Chai@ices.a-star.edu.sg)
Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 48, 1622–1632 (2010) V
2010 Wiley Periodicals, Inc.
C
1622
INTERSCIENCE.WILEY.COM/JOURNAL/JPOLA

ARTICLE
EXPERIMENTAL
Synthesis of Br-PEG(300)-Br Macroinitiator (PEGMI1)
At first, PEG (PEG(300)), 6 g, 0.02 mol) was diluted with dry
DCM (15 mL). Triethylamine (TEA, 4.05 g, 0.04 mol) was
then added with stirring. a-Bromoisobutyryl bromide (BiB,
Materials
0
Methyl methacrylate (MMA, 99%), 2,2 -dipyridyl (BiPy,
9
9þ%), styrene (St, 99þ%), methacrylic acid (MAA, 99%),
9.2 g, 0.04 mol) was diluted with DCM (10 mL) and added
ethyl a-bromoisobutyrate (EBiB, 98%), 4-dimethylaminopyri-
dine (DMAP, 99%), triethylamine (TEA, 98%), a-bromoisobu-
tyryl bromide (BiB, 98%), and all PEG samples were sup-
plied by Aldrich. CuBr (98%) was obtained from Acros.
dropwise. The reaction mixture was then stirred at room
temperature for 30 min and refluxed for 18 h. After cooling
the reaction flask, the contents were diluted with 100 mL
DCM and transferred to a separating funnel. It was then
washed with saturated brine solution (3 ꢀ 100 mL), satu-
rated sodium bicarbonate solution (3 ꢀ 100 mL), and again
with saturated brine solution (3 ꢀ 100 mL). The DCM layer
(
1-Bromoethyl)benzene (BEB, 97%) was purchased from
Lancaster. Glycerol 1,2-carbonate (GC, >93%) was supplied
0
by TCI. N,N -Dicyclohexylcarbodiimide (DCC, 99þ%) was
purchased from Fluka. a-Bromoisobutyric acid (BiBA, 98%),
was then dried over anhydrous MgSO and removed in a ro-
4
2-phenylethylamine (PEA, 99%), and lithium bis(trifluorome-
tary evaporator to produce a viscous liquid (Yield 8 g, 67%).
thane)sulfonimide (LiTFSI, 98%) were bought from Alfa
Aesar. Monomers MMA and St were purified by passing
through neutral Al O . N,N-Dimethyl formamide (DMF) and
2 3
dichloromethane (DCM) (HPLC grade) were passed through
a solvent purification system (Glass Contour) and used with-
out any further purification.
The ratio between the ACH
3
protons of bromoisobutyryl
unit and the terminal CH groups of PEG chain was found to
2
1
be 3.06 by H NMR spectroscopic analysis against the esti-
mated value of 3. Found: C, 41.54; H, 6.40, calculated
(
approximately) for Br-PEG(300)-Br or C H Br O : C,
21 38 2 4
4
3
4
2.14; H, 6.36. d (400 MHz; CDCl ): 1.72 (12H, s, CACH ),
H
3
3
.45 (18H, m, PEG CH
2
O), 3.52 (4H, t, PEG terminal CH
2
O),
.1 (4H, t, PEG terminal CH
2
O) (number of DP 6.5
(GPC, THF, PMMA
Instrumentation
(obtained); 6.4 (calculated)). Found M
n
NMR spectra were recorded on a 400 MHz Bruker Ultra-
Shield AVANCE 400SB spectrometer. Residual solvent peaks
were used as internal standard. A Digilab Excalibur Series
FTS3000 infra-red spectrometer was used to collect Fourier
Transform Infrared (FTIR) spectra. Elemental microanalysis
was performed using Eurovector E300 elemental analyzer.
High resolution mass spectra were recorded on Agilent 6210
TOF/LCMS. Thermogravimetric analysis (TGA) was carried
standard) 651, PDI 1.038; calculated for Br-PEG(300)-Br is
598 D.
Synthesis of Br-PEG(600)-Br Macroinitiator (PEGMI2)
The same procedure as described for PEG(300) was adopted.
The quantities used were: PEG(600) (6g, 0.01 mol), TEA
(
2.02g, 0.02 mol), BiB (4.6g, 0.02 mol), and DCM (50 mL).
The ratio between the ACH protons of bromoisobutyryl
unit and the terminal CH groups of PEG chain was found to
3
ꢂ
2
out under N2 atmosphere at a heating rate of 10 C/min
1
be 3.03 by H NMR spectroscopic analysis against the esti-
mated value of 3. Yield 7 g (78%). Found: C, 44.38; H,
using SDT-2960T TA Instruments. Contact angle measure-
ments were performed using CAM100 Contact Angle meter
from KSV Instruments. The instrument was fitted with a
Firewire camera with 640 ꢀ 480 pixel resolutions and
deionized water was used for measurement. The droplets
were allowed to stabilize for 5 s before measuring the con-
tact angle. Data collected were processed using the CAM100
software. Molecular weight and polydispersity index (PDI)
analysis of polymers were performed in two different Size
Exclusion Chromatography (SEC) systems using either THF
or DMF as eluent. The THF run SEC system was equipped
with Waters 515 HPLC pump, 717plus autosampler, 2414 re-
fractive-index detector. The following Styragel GPC columns
were arranged in series: guard, HR5E (ꢀ2, 4.6 mm ID ꢀ300
mm), HR1, and HR0.5. The eluent flow rate was 0.3 mL/min
7.36%; calculated (approximate) for Br-PEG(600)-Br or
C H Br O : C, 45.43; H, 7.13%. d (400 MHz; CDCl ): 1.7
3
4
64
2
16
H
3
(
12H, s, CACH
3
), 3.4 (44H, m, PEG CH
2
), 3.5 (4H, t, PEG ter-
minal CH O), 4.1 (4H, t, PEG terminal CH O) (number of DP
2
2
13 (obtained); 13.2 (calculated)). Found Mn (GPC, THF,
PMMA standard) 987, PDI 1.07; calculated for Br-PEG(600)-
Br is 898 D.
Synthesis of Br-PEG(2000)-Br Macroinitiator (PEGMI3)
16
PEGMI3 was prepared according to literature.
Synthesis of Cyclic Carbonate Methacrylate Monomer
DCC (12.231 g, 59.28 mmol), glycerol carbonate (GC, 7.0 g,
59.28 mmol), and DMAP (72 mg, 0.593 mmol) were dis-
solved in dry DCM (75 mL), and the solution was cooled in
an ice bath for 30 min. DCM solution (25 mL) of methacrylic
acid (MAA, 5.103 g, 59.28 mmol) was added dropwise to the
previous solution over a period of 30 min, and the stirring
was continued for another 30 min on ice bath. The mixture
was then brought to room temperature and stirred further
for 2[1/2] h. The white precipitated dicyclohexylurea
byproduct was filtered off and the clear product solution
was concentrated to 75 mL. The product solution was
washed with water (3 ꢀ 75 mL), dried over MgSO4, and
then concentrated to 20 mL in a rotary evaporator to
ꢂ
and the columns were maintained at 40 C. The DMF run
SEC system was equipped with a Viscotek GPCmax Pump
module, a Viscotek TDA 302 refractive index detector unit,
fitted with TOSOH HHR Guard Column and one TOSOH
GMHHR-M mixed bed column (5 lm, ID 7.8 mm ꢀ300 mm).
The eluent flow rate was 1.0 mL/min, and the columns were
ꢂ
maintained at 60 C. Impedance spectroscopy of polymer
electrolytes was recorded in an Autolab PGSTAT 302 electro-
chemical test system (Eco Chemie, Netherland). AC signal of
1
1
0 mv amplitude was applied over the frequency range of
.5 ꢀ 10 Hz to 1 Hz at 23 C.
5
ꢂ
METHACRYLATES BEARING CC GROUPS, JANA ET AL.
1623

JOURNAL OF POLYMER SCIENCE: PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
ꢁ
1
produce a white colored viscous liquid. The product was
cooled in a freezer for 40 h and then passed through a cot-
ton plug to remove crystallized urea byproduct (because of
the presence of highly polar nature of cyclic carbonate meth-
acrylate (CCMA) monomer, the urea byproduct was quite
soluble in the liquid monomer). The product was finally
purified by column chromatography using 9:1 DEE/hexane
mixture to produce colorless viscous liquid (yield 7.58 g,
(CC CH ), 5.121 (GC CH). FTIR mmax/cm (KBr): 2992, 1797
2
(CC carbonyl OCOO), 1733 (methacrylate COO), 1483, 1394,
1263, 1170, 1089, 1052, 771.
Triblock Copolymers P2 to P4 (PCCMA-b-PEG-b-PCCMA)
H NMR (d DMSO) d(ppm): 0.4–1.45 (methacrylate CH ),
1
6
3
1
.45–2.4 (backbone CH
2
), 3.545 (PEG CH
2
O), 3.645 (PEG ter-
minal CH
2 2
O), 3.9–4.65 (sidechain CC CH ), 4.663 (sidechain
CC CH ), 5.123 (sidechain CC CH). FTIR mmax/cm (KBr):
992, 1797 (CC carbonyl OCOO), 1733 (methacrylate COO),
483, 1395, 1263, 1169, 1089, 1051, 772.
ꢁ
1
2
67%).
2
1
Found C, 51.41; H, 5.62%; calculated for C
8
H
10
O
5
; C, 51.61;
þ
H, 5.41%. Mass m/z found [MþNa] ¼ 209.04229; Calcu-
lated for C H O 209.04204. d (CDCl ): 1.95 (3H, s, CH ),
Terpolymers P5 and P6 (PCCMA-st-PMMA-b-PEG-b-PMMA-
8
10
5
H
3
3
4
.33 (2H, m, CH ), 4.44 (1H, m, CH ), 4.58 (1H, t, CH ), 4.98
st-PCCMA)
H NMR (d
2
2
2
1
(1H, m, CH), 5.66 (1H, s, methacrylate CH ), 6.15 (1H, s,
6
DMSO) d(ppm): 0.4–1.35 (GC and MMA CH
), 3.59 (PEG CH O and
O), 3.95–4.55 (sidechain
3
),
2
methacrylate CH ). d (CDCl ): 18.16, 63.44, 66.07, 73.8,
1.4–2.4 (backbone (GC and MMA) CH
MMA OCH ), 3.85 (PEG terminal CH
2
2
2
C
3
127.35, 135.12, 154.44, 166.65.
3
2
CC CH ), 4.67 (sidechain CC CH ), 5.12 (sidechain CC CH).
2
2
ꢁ
1
Synthesis of Side Chain CC Polymers by ATRP
Synthetic procedure for copolymer P2 is mentioned later as
an example. All other polymers were synthesized by a simi-
lar method.
FTIR
m
max/cm (KBr): 2992, 2360, 1800 (GC carbonyl
OCOO), 1731 (methacrylate (both CCMA and MMA COO),
483, 1395, 1263, 1163, 1089, 1051, 772.
1
Synthesis of Partially Functionalized Side Chain
Hydroxyurethane Polymers by Ring-Opening
Reaction of CC Groups
CCMA (2 g, 10.743 mmol), Br-PEG(300)-Br macroinitiator
0
(PEGMI1) (64.2 mg, 0.107 mmol), and 2,2 -dipyridyl (BiPy,
67.1 mg, 0.429 mmol) were taken into a 25 mL Schlenk tube
Copolymer P2 (50 mg, ꢃ0.268 mmol with respect to CCMA
repeat unit) and 2-phenylethylamine, (PEA, 33 mg, 0.268
mmol) were dissolved in 1 mL of dry DMF and stirred at RT
for 70 h. DMF was removed in a high vacuum rotary evapo-
rator, and the polymer was dissolved in THF and precipitated
from excess of hexane (ꢃ30 mL). The white powdery prod-
and dissolved in dry DMF (5.35 mL) to make 2 mmol solu-
tion with respect to monomer. The mixture was immediately
frozen in liquid nitrogen after the addition of CuBr (30.8 mg,
0.215 mmol). The deep dark brown colored solution was
degassed by three freeze–pump–thaw cycles using N2 and
ꢂ
brought to room temperature and then heated at 80 C on
ꢂ
uct (P2U1) was then dried in a vacuum oven at 60 C over-
an oil bath under N atmosphere for 21 h. Usual Monomer:
2
night (yield 60 mg) and characterized. Polymer P2U1 was
Initiator:CuBr:BiPy ratio was 100:1:2:4. Targeted DP of
PCCMA block was 100. After polymerization, the solution
was diluted with DMF and then purified by passing through
neutral alumina column under gravity. The polymer solution
was then concentrated in a high vacuum rotary evaporator
and precipitated from excess MeOH. The white finely pow-
dered polymer was filtered off, washed with MeOH several
soluble in THF, DMSO, and DMF.
All other polymers (P1 and P3 - P6) were functionalized in
the same way to produce P1U1 and P3U1 to P6U1, respec-
tively. All partially functionalized polymers are soluble in
THF, DMSO, and DMF.
P2U1
ꢂ
times, and then dried in a vacuum oven at 75 C for 48 h
and used for characterization.
1
H NMR (d DMSO) d(ppm): 0.5–1.3 (methacrylate CH ), 1.4–
6
3
2
.3 (backbone CH ), 2.75 (PhCH ), 3.246 (CH NH), 3.379
2 2 2
EBiB was used as initiator to synthesize polymer P1 with
Monomer:Initiator:CuBr:BiPy ratio of 100:1:1:2. For P3 and
P6, Br-PEG(600)-Br (PEGMI2), for P4, Br-PEG(2000)-Br
(
PEG OCH ), 3.7–4.5 (sidechain CC CH ), 4.63 (sidechain CC
2 2
2 2
CH ), 4.8–5.0 (primary and secondary CH OH), 5.089 (side-
chain GC CH), 5.188 (NHCO), 7.1–7.4 (C H ). FTIR mmax/cm
ꢁ
1
6
5
(PEGMI3), and for P5, Br-PEG(300)-Br (PEGMI1) macroini-
(
KBr): 3402 (very broad, OH, H O and NH), 2949, 1798
2
tiators were used. For copolymers P5 and P6, MMA was
used as a comonomer and targeted DP of both individual
CCMA and MMA units were 50 each. St was used as a como-
nomer for polymer P7 and the polymerization temperature
was 100 C. Homopolymer P1 and copolymers P2 to P4
were soluble only in dipolar aprotic solvents like DMF and
DMSO and insoluble in common organic solvents like THF,
(
reduced intensity, OCOO), 1727 (overlapped multi peak,
COOMe and OCONH), 1531 (COHNCH ), 1481, 1454, 1395,
1
2
249, 1164, 1052, 769, 702. Found: C, 56; H, 6.3; N, 2.27%.
ꢂ
Synthesis of Highly Functionalized Side Chain
Hydroxyurethane Polymers by Ring-Opening Reaction of
CC Groups
Procedure is similar to that of the synthesis of partially func-
tionalized polymers. Only the initial compositions of reac-
tants are different. Typical composition for P2 functionaliza-
tion: copolymer P2 (120 mg, ꢃ0.645 mmol with respect to
CCMA repeat unit), PEA (94 mg, 0.776 mmol), and dry DMF
(1 mL).
3 2
CHCl , CH Cl2, but terpolymers P5 and P4 were soluble in
DMF and DMSO, acetonitrile and acetone.
Homopolymer P1 (PCCMA)
1
H NMR (d DMSO) d (ppm): 0.4–1.4 (methacrylate CH ),
6
3
1
.4–2.4 (backbone CH ), 3.9–4.5 (sidechain CC CH ), 4.664
2
2
1624
INTERSCIENCE.WILEY.COM/JOURNAL/JPOLA

ARTICLE
Synthesis of Fully Functionalized Side Chain
Hydroxyurethane Polymers by Ring-Opening
Reaction of CC Groups
Work up procedure is similar as for the synthesis of partially
functionalized polymers, but the reaction conditions are dif-
ferent. Typical composition for P2 functionalization: copoly-
mer P2 (50 mg, ꢃ0.268 mmol with respect to CCMA repeat
unit), PEA (65 mg, 0.536 mmol) in dry DMF (1 mL) stirred
ꢂ
at 80 C overnight.
SCHEME 1 Synthesis of CCMA monomer.
Film Formation and Contact Angle Measurement of
Polymers
sample and the whole assembly was placed in between two
mirror finished steel electrodes (12-mm diameter) covered
with Teflon casing to measure ionic conductivity. Sample
thickness was measured after the conductivity measurement.
For same amount of copolymers P5 and P6, only 9.6 mg of
LiTFSI was used as these are statistical terpolymer of CCMA
and MMA. For partially functionalized side chain hydroxyur-
ethane polymers P2U1 and P3U1, only 13.5 mg of LiTFSI
was used considering presence of at least 30% hydroxyur-
ethane groups. The impedance spectra of all samples were
Films of polymers P1 to P6 were cast on a glass microscope
slide using concentrated (20% w/v) polymer solutions and
then dried in a high vacuum oven at room temperature for
ꢂ
overnight followed by heating the oven at 45–50 C under
vacuum for 72 h. Clear films were produced but these films
are quite brittle. Contact angle of these polymer films were
then measured at room temperature using deionized water.
Films of polymers P1U1 to P6U1 and P1U2 to P6U2 were
cast on the glass surface using dilute (2% w/v) polymer sol-
utions in DMF and then dried and used for contact angle
measurement as mentioned earlier. These films were com-
pletely transparent and more uniform compared to the films
from polymers P1 to P6.
ꢂ
recorded at 23 C, and the resistance for each sample was
obtained by fitting circle to the kinetic control part of the
plot. In general, impedance spectra followed the Nyquist dia-
gram for mixed circuit. The resistance of each sample is
0
actually the real part of the resistance (Z ) where the imagi-
0
0
nary part of resistance (Z ) is assumed to be zero.
Crosslinking of Side Chain CC Polymers
Representative copolymer P2 (20–25 mg) was dispersed in
2–3 mL 5% (w/v) ethylene diamine solution in MeOH and
then stirred overnight either at room temperature or at 50
C in two separate reactions. The polymers were filtered off,
RESULTS AND DISCUSSION
ꢂ
Synthesis and Characterization of PEG Macroinitiators
and CCMA Monomer
washed with methanol several times, and finally dried in
ꢂ
vacuum oven at 60 C overnight. Quantitative amount of
PEG macroinitiators (PEGMI1 to PEGMI3) of varying molec-
ular weights were chosen to study the effect of PEG length
on various polymer properties like crystallizability, wettabil-
ity. The low molecular weight macroinitiators, Br-PEG(300)-
Br (PEGMI1) and Br-PEG(600)-Br (PEGMI2), were synthe-
sized by reacting respective dihydroxy terminated PEG
oligomers with a-bromoisobutyryl bromide (BiBB). The high
molecular weight macroinitiator, Br-PEG(2000)-Br (PEGMI3),
samples (P2C1 and P2C2 respectively, 20–23 mg in each
case) were recovered. Polymers were characterized by FTIR
and elemental microanalysis. The polymers were insoluble in
all common organic solvents including DMF and DMSO.
P2C1
FTIR mmax/cm
ꢁ
1
(KBr): 3372 (very broad, OH and NH),
2
1
992, 2954, 1798 (CC carbonyl OCOO, reduced intensity),
726 (methacrylate COO and urethane NHCOO), 1536 (new
0
was synthesized by N,N -dicyclohexylcarbodiimide (DCC)
peak HNCH ), 1479, 1453, 1395, 1265, 1165, 1101, 1051,
coupling of HO-PEG(2000)-OH with 2-bromoisobutyric acid
2
1
6
773.
(BiBA). PEGMI3 has also been prepared through the acid
1
7
halide route previously. We followed the DCC coupling
method as the acid halide route yielded a mixture of di- and
monoesterified products that were difficult to purify. All
P2C2
FTIR mmax/cm
ꢁ
1
(KBr): 3372 (very broad, OH and NH),
2
1
992, 2953, 1719 (methacrylate COO and urethane NHCOO),
536 (HNCH ), 1454, 1263, 1157, 1057, 775.
1
macroinitiators were characterized by HNMR spectroscopy,
2
elemental microanalysis, and SEC. For this study, CCMA
monomer was synthesized by DCC coupling between glycerol
1,2-carbonate (GC) and methacrylic acid (MAA) (Scheme 1).
The pure monomer was obtained after column chromatogra-
Lithium Ion Conductivity of Polymers
Polymer films were cast in between two flat circular copper
disks of 12 mm diameter to measure ionic conductivity. For
polymers, P1 to P4, 50 mg (ꢃ0.269 mmol with respect to
CCMA unit) of polymer sample was mixed with 19.3 mg
1
13
phy and characterized by H and C NMR spectroscopic
techniques, FTIR spectroscopy, elemental microanalysis, and
mass spectroscopy. CCMA monomer synthesized from GC
and methacryloyl chloride was highly sensitive to traces of
(
0.0672 mmol) of LiTFSI and dissolved in 0.13 mL of dry
DMF. The viscous solution was injected on a copper plate
and dried slowly under high vacuum first at RT overnight
ꢂ
acid and polymerized upon storing even at ꢁ20 C, and
ꢂ
and then with stepwise increase in temperature to 65 C for
hence DCC coupling method was adopted for the synthesis
of CCMA monomer.
72 h. Another copper disk was then placed on top of the
METHACRYLATES BEARING CC GROUPS, JANA ET AL.
1625

JOURNAL OF POLYMER SCIENCE: PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
TABLE 1 Kinetic Studies of the Polymerization of CCMA
tor ratio. The reaction conditions and molecular weight char-
acteristics of the homo- and copolymers are provided in
Table 3. Homopolymer of CCMA (i.e., PCCMA), P1, was syn-
thesized using ethyl a-bromoisobutyrate (EBiB) as initiator.
Three ABA type triblock copolymers P2 to P4 of the general
structure PCCMA-b-PEG-b-PCCMA with different PEG chain
lengths (300, 600, or 2000 Da, respectively) were synthe-
sized using the corresponding macroinitiators (PEGMI1 to
PEGMI3) under similar ATRP conditions by using CCMA as
the vinyl monomer (Table 3 and Scheme 2). (AC)B(AC) type
of statistical terpolymers P5 and P6 of general structure
PCCMA-st-PMMA-b-PEG-b-PMMA-st-PCCMA with different
PEG chain lengths (300 and 600 Da) were synthesized using
equimolar amounts of MMA and CCMA using PEGMI1 and
PEGMI2 macroinitiators, respectively. Attempted copolymer-
ization of equimolar mixtures of CCMA and St using PEGMI2
failed and no polymer was obtained.
Monomer Under ATRP
SEC
CCMA
d
Results
a
Time Conversion
Calculated
Observed
b
c
c
(
min) (%)
M
n
DP
M
n
M PDI
n
5
1
2
4
1
1
18
23
35
43
48
3,540
4,470
6,700
8,190
9,120
9,680
57
80
92
95
96
99
10,800
15,080
17,300
17,770
18,060
18,610
12,723 1.31
19,642 1.32
20,913 1.37
21,178 1.44
23,692 1.44
23,548 1.47
0
0
5
80
260 51
Reactions were carried out at 2 mM/mL concentration of CCMA in DMF
ꢂ
at 80 C with CCMA:BEB:CuBr:BiPy ¼ 100:1:1:2.
a
b
c
1
From H NMR spectra of reaction mixture.
1
Calculated from H NMR conversion.
From H NMR spectra of polymer.
1
d
Characterization of Side Chain CC Polymers
In DMF using PMMA standard.
Homo- and copolymers synthesized by ATRP were character-
1
13
ized by H and C NMR spectroscopic techniques, FTIR
spectroscopy, elemental microanalysis, and SEC (using DMF
as eluent). Polymer yields were good and the observed Mn
values from H NMR spectra and SEC matched well with the
n
calculated M values of the polymers (Table 3). Polydisper-
sity index (PDI) of these polymers (Table 3) was observed to
be 1.1–1.3. Homopolymer P1 and block copolymers P2 to
P4 are only soluble in DMF and DMSO and insoluble in other
common organic solvents. The terpolymers P5 and P6 are
soluble in acetonitrile and acetone along with DMF and
DMSO.
Synthesis of Side Chain CC Polymers by ATRP
Initial attempts to polymerize CCMA in toluene under ATRP
conditions were unsuccessful. When DMF was used instead
of toluene, the pure polymer could be obtained as a white
fine powder after work up and precipitation. To follow the
nature of polymerization, kinetic experiments were carried
out and these results are presented in Table 1. 1-Bromoethyl
benzene (BEB) was used as the initiator for the kinetic
1
1
experiments to estimate the molecular weight by H NMR
unambiguously using the proton signals of the aromatic ring.
As presented in Table 1, the monomer conversion increases
with time along with the molecular weight. However, the ini-
tiator efficiency was found to be 0.5. The polydispersity of
the polymers were moderately narrow. The polydispersity of
the polymer obtained by conventional free radical polymer-
ization (FRP) was much higher. Table 2 summarizes the
results of polymerization with varying monomer to initiator
ratio with two types of initiators, mono- and difunctional ini-
tiators. As can be noticed in Table 2, the molecular weight of
the polymer increases with the increasing monomer to initia-
The presence of methylene (AOCH A) resonance of middle
2
1
PEG block in the H NMR spectra of ABA type copolymers,
P2 to P4 (Fig. 1) near 3.6 ppm confirms the triblock struc-
ture. The homopolymer, P1, which was synthesized using
ethyl a-bromoisobutyrate (EBiB), does not show this reso-
nance (see Supporting Information Figure S1). As expected,
the intensity of the methylene (ACH A) resonance at 3.6
2
ppm increases (Fig. 1) from P2 to P4 due to the increasing
chain length of middle PEG block of the polymer. PEGylation
TABLE 2 Polymerization of CCMA Monomer Under Conventional FRP and ATRP
g
SEC Results
Initiator (I)
Used
CCMA/I
Ratio
CCMA
d
e
f
Polymer Structure
Conversion
%
Calculated M
n
Observed M
n
M
n
PDI
a
AIBN
PCCMA
88
100
50
93
51
62
81
94
92
86
c
ND
9,680
5,960
3,200
18,470
9,460
4,100
ND
18,620
14,520
7,070
43,160
23,548
18,650
12,383
19,348
14790
8,352
3.13
1.47
1.63
1.60
1.21
1.37
1.26
b
BEB
PCCMA
b
BEB
PCCMA
b
BEB
PCCMA
20
c
PEGMI2
PCCMA-b-PEG(600)-b-PCCMA
PCCMA-b-PEG(600)-b-PCCMA
PCCMA-b-PEG(600)-b-PCCMA
100
50
20,980
11,880
6,110
c
PEGMI2
c
PEGMI2
20
Reactions were carried out at 2 mM/mL concentration of CCMA in DMF
CCMA:PEGMI2:CuBr:BiPy ¼ 100:1:2:4.
1
ꢂ
d
e
f
at 80 C for 21 h.
From H NMR spectra of reaction mixture after polymerization.
1
ND, Not determined.
Free radical polymerization using 1.1 mol% of AIBN in DMF for 3 h.
Calculated from H NMR monomer conversion.
a
1
Calculated from H NMR spectra of polymer.
b
g
CCMA:BEB:CuBr:BiPy ¼ 100:1:1:2.
In DMF using PMMA standard.
1626
INTERSCIENCE.WILEY.COM/JOURNAL/JPOLA

ARTICLE
TABLE 3 Reaction Conditions and Molecular Weight Characteristics of Side Chain CC Polymers
i
SEC Results
f
Polymer
Code
Initiator
Used
Monomer
Yield
(%)
Calculated
Observed
e
g
h
Polymer Structure
Conversion (%)
M
n
M
n
M
n
PDI
a
c
P1
EBiB
PCCMA
CCMA: 92
72
73
75
55
39
17,320
16,350
18,470
17,540
9650
–
25,842
20,221
22,460
17,896
11,131
1.11
1.18
1.19
1.22
1.26
b
P2
PEGMI1
PEGMI2
PEGMI3
PEGMI1
PCCMA-b-PEG(300)-b-PCCMA
PCCMA-b-PEG(600)-b-PCCMA
PCCMA-b-PEG(2000)-b- PCCMA
CCMA: 84.6
17,900
20,980
19,060
11,250
b
P3
CCMA: 94.4
b
P4
CCMA: 81.9
c
P5
PCCMA-st-PMMA-b-PEG(300)-b-
PMMA-st-PCCMA
CCMA: 62 MMA: 66
c
P6
PEGMI2
PEGMI2
PCCMA-st-PMMA-b-PEG(600)-b-
PMMA-st-PCCMA
CCMA: 62MMA: 65
46
9930
–
11,690
Nil
11,024
–
1.24
–
d
P7
–
CCMA: nil St: nil
Nil
ꢂ
f
All reactions were carried out in DMF at 80 C for 21 h.
Obtained gravimetrically.
Calculated from H NMR spectroscopy based on the conversion of
a
g
1
CCMA:MMA:initiator:CuBr:BiPy ¼ 100:0:1:1:2.
b
CCMA:MMA:initiator:CuBr:BiPy ¼ 100:0:1:2:4.
monomers.
h
c
1
CCMA:MMA:initiator:CuBr:BiPy ¼ 50:50:1:2:4.
From H NMR spectra of polymer.
d
e
ꢂ
i
CCMA:St:initiator:CuBr:BiPy ¼ 50:50:1:2:4 and at 100 C.
In DMF using polystyrene standard.
1
Calculated from
H
NMR spectra of reaction mixture after
polymerization.
has no influence on the solubility of these copolymers as all
of these three copolymers (P2–P4) are only soluble in DMF
and DMSO like the homopolymer P1.
The structures of the (AC)B(AC) type statistical terpolymers
P5 and P6 (i.e., PCCMA-st-PMMA-b-PEG-b-PMMA-st-PCCMA)
1
were confirmed by H NMR (Fig. 2) and FTIR spectroscopy
(
Fig. 3). For these terpolymers, PEG methylene (AOCH ) and
2
In the case of (AC)B(AC), terpolymers monomer conversions
are lower and PDI is slightly higher than P1 to P4. Interest-
ingly, it has been observed that the conversion of CCMA and
MMA at the end of polymerization as determined by the
MMA methoxy (AOCH ) resonances overlap and appears
around 3.6 ppm. Most importantly, in the H NMR spectra of
3
1
these terpolymers, the ratio of backbone methylene group
and CC methyne group was nearly 4, which was exactly 2
for P1 (see Supporting Information Figure S1) and P2 to P4.
This is due to the presence of equal number of repeat units
derived from CCMA and MMA units. In the FTIR analysis, the
1
HNMR spectroscopic analysis was found to be similar. This
occurs throughout the polymerization reaction as indicated
by the NMR spectroscopic analysis. This showed that both
CCMA and MMA monomers were consumed for polymeriza-
tion simultaneously. The terminal blocks of these two ter-
polymers were in fact a statistical copolymer of CCMA and
MMA units. Both of these terpolymers P5 and P6 showed
improved solubility characteristics because of the presence
of MMA based repeat units. These terpolymers are soluble in
acetonitrile and acetone apart from being soluble in DMF
and DMSO.
ꢁ
1
relative intensity of ester carbonyl group (1732 cm ) to the
CC carbonyl group (1798 cm ) of these terpolymers (P5
ꢁ
1
1
FIGURE 1 H NMR spectra of copolymers (i) P2, (ii) P3, and (iii)
0
00
P4 (c and c are two hydrogen atoms at c methylene unit of
SCHEME 2 Synthesis of side chain CC polymers by ATRP.
structure inset).
METHACRYLATES BEARING CC GROUPS, JANA ET AL.
1627

JOURNAL OF POLYMER SCIENCE: PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
1
FIGURE 2 H NMR spectrum of copolymer P5.
FIGURE 4 Size exclusion chromatograms of side chain CC
and P6) was higher than homopolymer P1 (and copolymers
P2–P4) because of the presence of MMA based repeat units
polymers.
Size exclusion chromatograms for all these side chain CC
polymers were monomodal (Fig. 4) and PDI obtained were
narrow. The observed molecular weight correlated well with
the calculated molecular weights (Table 3).
ing/cooling rates under nitrogen atmosphere from ꢁ50 to
ꢂ
150 C did not reveal any significant phase changes.
Functionalization of Side Chain CC Polymers, P1–P6
Thermal Properties of Polymers
TGA of the homo- and copolymers P1 to P6 (Fig. 5) indi-
cated that the polymers were stable up to 200 C.
Homopolymer P1 and copolymers P2 to P4 degrade in two
Cyclic carbonate (CC) groups undergo ring-opening reactions
6
,8
with a number of nucleophiles. The most widely studied
reaction among these is aminolysis, that is, the reaction of
CC group with amines. The reaction condition used is nor-
mally mild and the extent of ring opening depend on solvent
ꢂ
steps, presumably by the elimination of CO from CC ring at
2
8
,18,19
first followed by degradation of the polymer backbone. Inter-
estingly, no clear stepwise degradation was observed for ter-
polymers P5 and P6. This is most likely due to the decrease
in CC unit concentration in these terpolymers. These statisti-
cal terpolymers contain lesser CC units; hence, the amount
polarity, reaction temperature etc.
Reaction of small
molecule containing CC group with primary amines yields a
mixture of primary and secondary hydroxyurethanes with
1
8
about 1:4 ratio. All these reactions on CC groups were
studied with the aim of applying pendant CC functional poly-
mers as thermosetting coating materials or for the synthesis
of linear hydroxyurethane polymers. In this study, we
adopted this method of functionalization to modify the solu-
bility and wettability properties of polymers P1 to P6 and
also to access controlled polymers with multiple functional
groups.
2
of CO released also would be lower than the homopolymer
P1. The presence of remaining MMA repeat units might be
helping to reduce the degradation of CC units if not com-
pletely eliminated. This could also be due to the alternating
arrangement of GCMA and MMA units. Low temperature DSC
ꢂ
measurement of these copolymers at 10, 20, and 30 C heat-
FIGURE 3 FTIR spectra of copolymers (i) P2 and (ii) P5.
FIGURE 5 Thermogravimetric analysis of side chain CC polymers.
1628
INTERSCIENCE.WILEY.COM/JOURNAL/JPOLA

ARTICLE
SCHEME 3 (a) Partial and (b)
complete functionalization of side
chain CC polymers with PEA.
Functionalization of side chain CC polymers was achieved by
ized polymers were lower than expected most probably
because of strong interaction of a range of polar functional-
ities present in these polymers with the SEC columns. The
possibility of aminolysis of main chain ester groups present
in the termini of PEG blocks of the polymers P2 to P6 is
ruled out because of the presence of PEG methylene group
2-phenylethylamine (PEA). PEA was chosen to calculate the
extent of ring opening quantitatively by making use of the
aromatic proton signals which are well separated from other
signals in the polymer. Functionalization of side chain CC
polymers (P1–P6) by ring-opening reaction of CC groups
with equimolar amounts of PEA in DMF at room temperature
yielded partially functionalized side chain hydroxyurethane
polymers (P1U1–P6U1, respectively), and the reaction was
observed to be slow (Scheme 3). Only about 40% of CC
groups were converted to hydroxyurethanes after 3 days of
reaction as estimated by the nitrogen content of the ring
opened polymers in elemental microanalysis. However, this
conversion was sufficient to greatly affect the solubility char-
acteristics of the polymers. The homo- and copolymers (P1–
P4) were only soluble in dipolar aprotic solvents like DMF
and DMSO, whereas the partially functionalized polymers
1
signals in the H NMR spectra of these functionalized copoly-
mers (Fig. 6 and Supporting Information Figure S3). A simi-
lar type of observation has also been made by Endo and co-
workers during the aminolysis of their model low molecular
1
8
weight CC compound.
When ring-opening reactions of side chain CC polymers (P1–
P6) were carried out at higher concentrations in DMF using
20% molar excess of PEA, 90% CC groups were functional-
ized as estimated by elemental microanalysis (Table 4).
These highly functionalized polymers were soluble in a wide
range of organic solvents including CHCl3 and THF. The
(P1U1 - P6U1) produced were soluble in common organic
solvents like acetonitrile and THF. This may be due to the
reduction in the rigidity of the backbone, which is accompa-
nied by an increase in entropic contribution of the newly
formed side chain. The presence of additional signals at 7.2–
7.4 ppm due to the phenyl groups, at 2.2–2.3 and 3.2–3.3
ppm due to the methylene units, at 4.7–5.0 ppm due to the
hydroxyl group, and at 5.2–5.3 ppm due to the urethane
1
NAH group together with CC group resonances in the
H
NMR spectra of these partially functionalized polymers (Fig.
6
) confirms the partially ring opened cyclic carbonates. The
ꢁ
1
reduction in CC carbonyl group intensity (at 1798 cm ) and
increased intensity at 1732 cm (urethane carbonyl group)
ꢁ
1
ꢁ
1
and 1531 cm (urethane ANHA group) in the FTIR spectra
Supporting Information Figure S2 ) also support the poly-
mer structure. The narrow PDI values of these copolymers
<1.4) obtained in SEC using THF as eluent confirmed the
(
(
1
controlled structures of these partially (ꢃ40%) functional-
FIGURE 6 H NMR spectrum of partially functionalized polymer
ized polymers. The M values of these partially functional-
P2U1.
n
METHACRYLATES BEARING CC GROUPS, JANA ET AL.
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JOURNAL OF POLYMER SCIENCE: PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
TABLE 4 Characteristics of Highly Functionalized Side Chain CC Polymers
b
Before Functionalization
Elemental Data
After Functionalization
SEC Results
Elemental Data
H
Polymer
New Polymer
Code
Code
C
H
N
C
N
M
n
M
z
PDI
P1
50.47
4.94
Nil
P1U2
61.89
62.12
61.86
60.16
63.23
61.88
60.51
6.97
7.49
6.85
6.70
7.41
7.28
7.14
4.06
4.53
3.94
4.12
4.08
3.04
3.18
16,365
–
23036
1.41
–
a
P1U3
–
P2
P3
P4
P5
P6
a
51.33
51.40
49.82
54.48
53.40
5.07
5.07
5.29
5.72
6.00
Nil
Nil
Nil
Nil
Nil
P1U2
P3U2
P4U2
P5U2
P6U2
19,152
21,541
14,325
12,833
13,105
25,402
28,459
19,285
19,427
20,335
1.33
1.32
1.35
1.51
1.55
Calculated elemental values for fully functionalized PCCMA, P1.
b
In THF.
structures of these highly functionalized polymers (P1U2–
P6U2) were confirmed by H NMR (see Supporting Informa-
P6 are higher than other copolymers, and this may be due
to the presence of the hydrophobic MMA repeat units.
1
tion Figure S4) and FTIR spectra (Supporting Information
Figure S2) and SEC using THF as eluent (Table 4). The mo-
lecular weight of these highly functionalized (P1U2–P6U2)
polymers was observed to be higher than the partially func-
tionalized (P1U1–P6U1) polymers.
Interestingly, functionalization of these side chain CC poly-
mers also had substantial influence on the surface proper-
ties. The partially and highly functionalized polymers
(P1U1–P6U1 and P2U1–P6U2) derived from the ring open-
ing of cyclic carbonates showed much improved film-forming
properties. The improved film forming tendency may be due
to the increased interaction between polymer chains caused
by hydrogen bonding and also due to the decreased rigidity
of the backbone. Films are completely uniform, transparent,
and adherent on glass surface. Continuous films could be
obtained using much lower concentrations of polymer solu-
tions. The contact angle with water increases continuously
with the degree of functionalization (Table 5) in spite of the
presence of increased amount of polar hydrophilic hydroxyl
groups. This increase was not totally unexpected as the sur-
face property is dependent on the overall changes in hydro-
phobic to hydrophilic ratio caused by PEA derived side
groups. It may be possible to influence the surface
Synthesis of representative fully functionalized polymer
(P2U3) was carried out by quantitative ring opening of CC
groups of polymer P2 using 100% molar excess of PEA at
ꢂ
8
0 C overnight in DMF. The polymer P2U3 was also charac-
1
terized by H NMR (see Supporting Information Figure S5),
FTIR spectroscopy (see Supporting Information Figure S2),
and SEC (Fig. 7).
In general, the functionalization of side chain CC polymers
by ring-opening reactions of CC groups leads to the forma-
tion of block copolymers or terpolymers with a diverse vari-
ety of functionalities present as pendant groups. The par-
tially and highly functionalized polymers synthesized here
contain ester, primary hydroxyl, secondary hydroxyl, ure-
thane, cyclic carbonate, and phenyl groups (Fig. 6 and Sup-
porting Information Figures S6 and S7) as side chains which
can be further chemically modified by many reactions. Such
modified, multiple functionalized materials may have poten-
tial applications in many areas.
Film Formation and Contact Angle Measurement of Side
Chain CC Polymers in Water
Polymer films were cast on glass plates using concentrated
solutions of polymers P1–P6 in DMF. Subsequent drying
under vacuum produced continuous films, and the measured
contact angles in water are presented in Table 5. In general,
films produced from polymers with high CC content were
brittle. Among all the polymers synthesized, the statistical
terpolymers P5 and P6 showed better film-forming proper-
ties. These films were less brittle and completely transpar-
ent. Contact angles (Table 5) of P3 and P4 in water are
lower than P2 probably due to the presence of longer hydro-
philic PEG blocks. The contact angles of terpolymers P5 and
FIGURE 7 Size exclusion chromatograms of partially and fully
functionalized CC polymers. [Color figure can be viewed in the
online issue, which is available at www.interscience.wiley.
com.]
1630
INTERSCIENCE.WILEY.COM/JOURNAL/JPOLA

ARTICLE
TABLE 5 Wettability Characteristics of Side Chain CC Polymers with Water
Side Chain CC Polymer Partially Functionalized Polymer
Polymer Average Contact
Highly Functionalized Polymer
Functionalized
Average Contact
Angle (degree)
Functionalized
Polymer Code
Average Contact
Angle (degree)
Code
Angle (degree)
Polymer Code
a
P1
P2
P3
P4
P5
P6
a
–
P1U1
P2U1
P3U1
P4U1
P5U1
P6U1
71.4 6 2.1
71.3 6 1.5
75.3 6 1.6
71.3 6 1.6
75.0 6 2.1
76.3 6 1.1
P1U2
P2U2
P3U2
P4U2
P5U2
P6U2
77.6 6 0.4
77.6 6 1.8
79.5 6 0.5
78.5 6 0.4
83.3 6 1.2
78.3 6 0.6
67.0 6 2.0
64.3 6 0.7
57.3 6 0.6
68.7 6 1.5
74.9 6 1.9
Continuous film could not be formed.
characteristics toward hydrophilicity by suitably choosing
the amine for ring-opening reactions.
and thermal stability of the polymers synthesized were
studied thoroughly. (AC)B(AC) type terpolymers showed
improved solubility, film-forming property, and thermal sta-
bility because of the presence of additional MMA repeat
units. In the TGA analysis, ABA type block copolymers
showed two step degradation curves due to the presumed
elimination of CO2 in the first step followed by the disinte-
gration of the polymer backbone. The statistical (AC)B(AC)
type terpolymers did not show stepwise degradation.
These side chain cyclic carbonate polymers were subjected
to ring-opening reaction of pendant CC group by mono- and
diamines. Treatment with monoamines yielded side chain
hydroxyurethane polymers of controlled structure with
vastly improved solubility and film-forming characteristics.
The use of diamine in the ring opening process yielded in-
soluble, crosslinked polymers. All these polymers synthe-
sized with CC pendant groups showed lithium ion conductiv-
ity when blended with lithium bis(trifluoromethane)
sulfonamide.
Lithium Ion Conductivity of Side Chain CC Polymers
Ethylene and propylene carbonates are well-known organic
liquids used in commercial lithium ion batteries because of
their solvating power to lithium ion. Lithium ions are sol-
3
,5
vated in these liquids with a tetrahedral solvent shell.
However, lithium ion batteries which contain these types of
liquid electrolytes pose potential safety hazard in case of
overheating and accident due to their flammable nature.
Solid- or gel-based materials with similar functional charac-
þ
teristics are suitable substitutes. The Li ion conductivity of
some of the side chain CC bearing controlled polymers
reported here was also studied. Polymers were mixed with
lithium bis(trifluoromethane)sulfonimide (LiTFSI) in 4:1 ra-
tio of CC units in DMF and films were cast. After drying im-
pedance spectra were recorded. Films produced from CC
rich homopolymer and copolymers P1 to P4 with LiTFSI
were nontransparent and brittle, and the films produced
from statistical terpolymers P5 and P6 were transparent
and uniform (see Supporting Information Figure S10). Gener-
ally, two types of impedance spectra were observed (see
þ
The authors thank T. Zhiqun for the help rendered in Li ion
conductivity studies. This work was supported by the Science
and Engineering Research Council of A*STAR (Agency for Sci-
ence, Technology and Research), Singapore.
þ
Supporting Information Figure S11). Li ion conductivity of
some of the partially functionalized copolymers (P2U1 and
P3U1) were also studied (see Supporting Information Figure
S11). Films produced from LiTFSI mixed with partially func-
tionalized polymers were uniform and transparent (see Sup-
porting Information Figure S10) unlike those obtained from
P2 and P3. The conductivities of the side chain CC polymers
REFERENCES AND NOTES
1
Ghosh, B.; Urban, M. W. Science 2009, 323, 1458–1460 and
references therein.
ꢁ
6
ꢁ1
2 Golden, J. H.; Chew, B. G. M.; Zax, D. B.; DiSalvo, F. J.; Frechet,
analyzed here were in the range of 2–5 ꢀ 10 Scm at
ꢂ
J. M. J.; Tarascon, J. M. Macromolecules 1995, 28, 3468–3470.
2
3 C.
3
Tarascon, J. M.; Armand, M. Nature 2001, 414, 359–367.
CONCLUSIONS
4
Dias, F. B.; Plomp, L.; Veldhuis, J. B. J. J Power Sources
Synthesis of block copolymers and statistical terpolymers
bearing pendant CC groups from PEG macroinitiators of
varying molecular weight with controlled structure by ATRP
are reported for the first time. A few novel ABA type triblock
copolymers and (AC)B(AC) type terpolymers with statistical
arrangement of A and C monomers were prepared. The side
chain CC rich homopolymer and ABA type triblock copoly-
mers were soluble only in dipolar aprotic solvents like
DMSO, DMF. The solubility, film forming property, wettability,
2000, 88, 169–191.
5
Britz, J.; Meyer, W. H.; Wegner, G. Macromolecules 2007, 40,
558–7565.
7
6
Webster, D. C. Prog Org Coat 2003, 47, 77–86 and references
therein.
7
Endo, T.; Kakimoto, K.; Ochiai, B.; Nagai, D. Macromolecules
005, 38, 8177–8182.
2
8 Webster, D. C.; Crain, A. L. Prog Org Coat 2000, 40, 275–282.
METHACRYLATES BEARING CC GROUPS, JANA ET AL.
1631

JOURNAL OF POLYMER SCIENCE: PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
9
1
Ochiai, B.; Endo, T. Prog Polym Sci 2005, 30, 183–215.
15 Braunecker, W.; Matyjaszewski, K. Prog Polym Sci 2007, 32,
3–146.
9
0 Ochiai, B.; Iwamoto, T.; Miyazaki, K.; Endo, T. Macromole-
cules 2005, 38, 9939–9943.
1 Ochiai, B.; Matsuki, M.; Nagai, D.; Miyagawa, T.; Endo, T. J
Polym Sci Part A: Polym Chem 2005, 43, 584–592.
2 Park, S. Y.; Lee, H. S.; Ha, C. S.; Park, D. W. J Appl Polym
Sci 2001, 81, 2161–2169.
3 Golden, J. H.; DiSalvo, F. J.; Frechet, J. M. J.; Silcox, J.;
Thomas, J.; Elman, J. Science 1996, 273, 782–784.
4 Matyjaszewski, K.; Xia, J. Chem Rev 2001, 101, 2921– 2990.
16 Siegwart, D. J.; Wu, W.; Mandalaywala, M.; Tamir, M.;
Sarbu, T.; Silverstein, M. S.; Kowalewski, T.; Hollinger, J. O.;
Matyjaszewski, K. Polymer 2007, 48, 7279–7290.
1
1
7 Jankova, K.; Chen, X.; Kops, J.; Batsberg, W. Macromole-
1
cules 1998, 31, 538–541.
1
18 Steblyanko, A.; Choi, W.; Sanda, F.; Endo, T. J Polym Sci
Part A: Polym Chem 2000, 38, 2375–2380.
1
19 Kihara, N.; Endo, T. Makromol Chem 1992, 193, 1481–1492.
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