measurement. Pairs of obtained BDWand OD data were used todevelop
a calibration curve.
2.7.2. Determination of polymer molecular weight (M
n
and M
w
), dispersity
(D
w/n
) and amine content (mol-%)
Copolymer molecular weights (MWs) were determined using a gel
permeation chromatography (GPC) (Waters Alliance GPCV 2000)
equipped with a refractive index detector. Two columns were used in
series; the
fi
rst was a Waters Styragel HT4, followed by an Agilent
PolarGel-L column. The mobile phase consisted of N, N-dimethyl-
formamide (DMF) with 0.05 M lithium bromide (LiBr) at 42 °C with a
fl
ow rate of 1 mL/min. Samples were dissolved in the mobile phase at
0.5 mg/mL and
fi
ltered using 0.2
μ
mTe
fl
on syringe
fi
lters. MWs were
reported as polystyrene equivalent molecular weights. Polymer D
w/n
was equal to the ratio between M
w
and M
n
. The M
n
and M
w
were in
the range of 52,000 to 166,000 and 73,000 to 368,000, respectively.
The resultant D
w/n
ranged from 1.40 to 2.22