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This suggests that the model compound
B
was not stable at room temperature
when compared to model compound
A
in the presence of water after 8 hours of
storage. The model compound
was found to be stable at RT in presence of wa-
ter even after 1 week (Figure 9), whereas the NMR spectrum of model compound
B
A
containing SiDA showed amine peak even at room temperature in presence of
water in just 8 hours (Figure 10). Therefore, it suggests that model compound
is
following a reverse order reaction (degradation) through hydrolysis in the pres-
ence of water to give amine which appeared as a peak at 2.8 ppm. This confirms
that the model compound
B
is not stable at room temperature and starts decom-
posing into amine (Figure 10 bottom two spectra).
B
3.2. Monitoring changes in bulk viscosity, inherent viscosity, molecular weight
and acid number
The inherent viscosity, molecular weight and acid number were determined be-
fore and after one month of storage at RT. Bulk viscosity, inherent viscosity, mo-
lecular weight and acid number all decreased irrespective of the chemical compo-
sition and chemical structure of Co-PAA and Co-PDPAA (Tables 1 and 2).
The change in bulk viscosity, inherent viscosity, molecular weight and acid
number of PAA, Co-PAA and Co-PDPAA were studied for 1 month during stor-
age at RT. For bulk viscosity, the sample was tested once a week. The results are
shown in Figures 11 and 12.
Figure 11. Bulk viscosity as a function of storage time at 25°C for BTDA based polymer systems.
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