Sample Name:
ω-Carboxyl Terminated Poly(ethylene glycol) methyl
ether (O-Acetic Acid Ester Terminal group)
Characterization:
The molecular weight and polydispersity index of this
polymer
were
determined
by
size
exclusion
chromatography (SEC) using a Varian liquid
chromatograph equipped with a UV and refractive index
detector.
Functionality:
Functionality of the polymer was
determined by H NMR analysis or FT-IR spectroscopy.
Solubility:
Polymer is soluble in water, methanol and ethanol, THF,
CHCl3.
It is precipitated out from cold ethanol,
isopropanol, hexane and ether.
Sample #: P14172-EGOCH3CH2COOH
Structure:
O
H 3CO
CH 2
CH 2
O
n
CH 2
Composition:
Mn × 103
C
OH
PDI
2.0
NMR of Sample:
1.09
COOH Functionality by
HNMR
COOH functionality by
titration
0.88
2500
0.93
2000
Synthesis Procedure:
Carboxy terminated poly(ethylene glycol) was synthesized
by anionic living polymerization of ethylene oxide using
ethylene glycol/potassium salt as an initiator. The hydroxyl
end groups were converted into carboxyl groups by
reacting them with 2-bromoacetate or using Jones Reagent
(CrO3 H2SO4) as oxidizing agent.
The reaction is
illustrated as Scheme 1.
P14172-EGOCH3CH2COOH
1500
1000
500
0
1
.7
5
1
7
1
.0
6
4.00
ppm (f1)
3
.0
0
3.50
3.00
SEC of Polymer:
P14172-EGOCH3CH2COOH
or:
H3 C
0.12
O
CH2
CH2
O
CH2
CH2
O
CH2
CH2
OH
n
CrO3/H2SO4
3.3ppm
0.06
O
A
H3 C
O
CH2
CH2
O
CH2
CH2
O
CH2
OH
8
n
3.3ppm
C
0.00
10
12
14
16
18
20
22
24
26
28
Ve (ml)
4.1pm
Size Exclusion Chromatography of Polyethylene glycol methyl ether
before converting terminal OH to COOH Mn=2000, Mw=2200, PI=1.09
It elution retarded; By converting terminal COOH back to its ester (A):