Chemistry Reference
In-Depth Information
Figure 9.2:
Transmission electron micrograph of a PDMS network containing 34.4 wt % in situ pre-
cipitated silica particles.
92
The length of the bar corresponds to 1,000 Å.
Reproduced by permission of John Wiley and Sons.
A
B
Figure 9.3:
1
H NMR images of a SiO
2
-PDMS elastomeric sample obtained with a two-dimensional
spin echo sequence having an echo time of 3.3 ms (portion A) and 22.7 ms (portion B).
99
The view is down the axis, and the resolution is 128 X by 128 pixels of 211 and 236 mm,
respectively (in A), and 211 mm in both axes (in B).
reactions, including titania.
42,
93-97
In some cases, the particles are formed
in a separate step, and then blended into the polymer.
98
In the in situ approach, the growth of the particles from the surface of
a PDMS sample can be followed by NMR (figure 9.3) utilizing
1
H and
29
Si
magic-angle spinning, with two-dimensional Fourier transform spin-
echo techniques.
99
he
1
H spin-spin (T
2
) relaxation time of the protons in
