Thermal analysis and FTIR studies of adsorbed poly(ethylenestat-vinyl acetate) on silica
Madhubhashini Maddumaarachchi and Frank D Blum
A. Expanded carbonyl stretching regions of
FTIR spectra of bulk and adsorbed PVAc
homopolymer and PEVAc copolymers
The expanded carbonyl stretching regions of
FTIR spectra of bulk and adsorbed samples of
PVAc homopolymer and PEVAc copolymers are
shown in Figures A1-A5. Adsorbed amounts are
expressed in mg polymer/m2 silica. The spectra
are in the order as shown in the legend except for
the bulk PEVAc in the region for free carbonyl
resonance. Except for the bulk PEVAc, the
spectra have been normalized to the height of the
bound carbonyl peak. The relative intensity of
free carbonyls increased with an increase in the
adsorbed amount of the polymer.
0.54
Bulk
1750
1700
1650
Wavenumbers (cm-1)
Figure A1. Expanded carbonyl stretching region
of bulk and adsorbed PVAc with different
adsorbed amounts in mg/m2.
1550
Figure A2. Expanded carbonyl stretching region
of bulk and adsorbed PEVAc (70% VAc) with
different adsorbed amounts in mg/m2.
Absorbance, A.U.
0.78
1.58
1.24
1.04
0.84
0.47
Bulk
1750
1650
Wavenumber (cm-1)
0.88
Absorbance, A.U.
1800
Absorbance, A.U.
Supporting Information
1.34
0.94
0.84
0.73
0.43
1750
1650
1550
Wavenumber (cm-1)
Figure A3. Expanded carbonyl stretching region
of bulk and adsorbed PEVAc (40% VAc) with
different adsorbed amounts in mg/m2.
1800
1700
1600
Wavenumber (cm-1)
1500
1800
Figure A4. Expanded carbonyl stretching region
of bulk and adsorbed PEVAc (33% VAc) with
different adsorbed amounts in mg/m2.
Absorbance, A.U.
1.66
1.28
1.19
0.85
0.45
Bulk
1750
1650
Wavenumber
1.99
1.73
1.34
0.89
0.42
Bulk
Absorbance, A.U.
Absorbance, A.U.
2.28
1.88
1.50
1.33
1.04
0.81
0.46
Bulk
1550
(cm-1)
Figure A5. Expanded carbonyl stretching region
of bulk and adsorbed PEVAc (28% VAc) with
different adsorbed amounts in mg/m2.
1700
1600
Wavenumber (cm-1)
1500
Figure A6. Expanded carbonyl stretching region
of bulk and adsorbed PEVAc (18% VAc) with
different adsorbed amounts in mg/m2.
An example of the fitting of the FTIR
resonances in the carbonyl region of the adsorbed
PEVAc (28% VAc)-0.85 mg/m2 before and after
removing adsorbed water is shown in Figures B1
and B2, respectively. A Gaussian line shape was
used to fit free carbonyl resonance and GaussianLorentzian mixture was used to fit bound carbonyl
and adsorbed water resonances using OriginPro
8.6 software (OriginLab, Northampton, MA,
USA).
Experimental
Absorbance, A.U.
Free carbonyl
Bound carbonyl
Adsorbed water
1800 1750 1700 1650 1600 1550
Wavenumber (cm-1)
Figure B1. Example of the fitting for the carbonyl
region of the FTIR spectrum of adsorbed PEVAc
(28% VAc) (0.85 mg/m2) before removing
adsorbed water.
Absorbance, A.U.
B. Comparison of fittings of free and bound
carbonyls resonances before and after
removing adsorbed water
1800
Experimental
Free carbonyl
Bound carbonyl
1750
1700
1650
Wavenumber (cm-1)
1600
Figure B2. Example of the fitting for the carbonyl
region of the FTIR spectrum of adsorbed PEVAc
(28% VAc) (0.85 mg/m2) after removing adsorbed
water.
C. Comparison of the amount of bound
polymer (Mb) and the ratio of molar absorption
coefficients of bound and free carbonyl
resonance (X) values obtained before and after
removing the water present in PEVAc (28%
VAc)-silica samples
Adsorbed amount, Mt
(mg/m2)
Figure C1 shows graphs of the total adsorbed
amount as a function of ratio of peak areas of free
carbonyl resonances to bound carbonyl
resonances for PEVAc (28%VAc)-Silica obtained
before and after removing adsorbed water.
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
Table C1 shows the Mb and X values for
adsorbed PEVAc (28% VAc) copolymer samples
obtained before and after removing adsorbed
water. The Mb and X values in both cases were
very close to each other. Therefore, this proves
that the presence of adsorbed water does not
affect the relative intensities of free and bound
carbonyl resonances.
Before removing water
After removing water
0
0.2
Af/Ab
0.4
Figure C1. The plot of total adsorbed amount as a
function of the ratio of the absorbance of the free
and bound carbonyl resonances for PEVAc (28%
VAc)-Silica samples before and after removing
water. The lines represent the linear least square
fits of the experimental data.
Table C1. Effective amount of bound polymer (Mb) and ratio of molar absorption coefficients of bound
and free carbonyl resonance (X) for adsorbed PEVAc (28% VAc) copolymer before and after removing
bound water. The Mb value represents the effective mass and should not be taken as a layer thickness.
Mb (mg/m2)
Condition
Before removing
adsorbed water
X
0.376 ± 0.048
9.3 ± 1.3
After removing most
of the adsorbed water
0.387 ± 0.042
8.9 ± 1.1