Chemistry Reference
In-Depth Information
Cyclics
Linears
0
1/M
Figure 3.3:
The asymptotic effect of molecular weight on some property such as the glass transition
temperature for cyclic and linear polysiloxanes.
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Vs.
Vs.
Figure 3.4:
Cutting a cyclic to form two chains (solid circles) can have less of an effect in the case of
high molecular weight.
examples. In general, differences that appear at low molecular weight can
decrease significantly at higher molecular weight, as occurs in the case of
the glass transition temperature.
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Figure 3.3 illustrates this effect. Cut-
ting a skeletal bond in a cyclic of high molecular weight can have much less
effect on some properties than cutting a skeletal bond in a smaller cyclic,
as illustrated schematically in figure 3.4.
3.6 OTHER NOVEL MATERIALS
3.6.1 Blends
There have been numerous studies of blends based on the polysiloxanes.
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Blends with polystyrene are of particular interest,
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including some
