Chemistry Reference
In-Depth Information
3. RESULTS AND DISCUSSION
3.1. NMR spectroscopic analysis of model compounds
NMR spectra indicated that the amic acid model compound
was sufficiently
stable under the experimental conditions and that no chemical reactions were oc-
curring to cause any structural changes detectable by NMR. Since the spectra
(Figures 8-9) of the water treated model compound
A
remained the same as the
untreated one, it can be inferred that more drastic conditions other than presence
of water are needed to bring about any perceptible change.
In the NMR spectra (Fig. 10 top) of siloxane diamine (SiDA), the amine pro-
tons appear at 2.6 ppm. However, in the spectrum of model compound
A
this peak
was not present at room temperature when it was synthesized, which confirmed
that the prepared compound was devoid of unreacted amine and was pure. How-
ever, after the water treatment and storage for 8 hours, there was a change in the
NMR spectra of
B
at 10 and 20% added water at RT. At the end of 8 hours study,
a peak corresponding to an amino group was observed at 2.8 ppm both at 10 and
20% water contents.
B
Figure 8. NMR study of model compound A: Effect of 0, 10 and 20% water content at RT.
Search WWH ::
Custom Search