Chemistry Reference
In-Depth Information
Figure 7.
An example of weight change curve showing a determination of the durations of induction period (t
di
).
polypropylene degradation has not been
comprehensively studied with the viewpoint
of a stereochemical reaction. The reason for
this is that it is difficult to prepare a series
of polypropylene resins with various tacti-
cities.
As shown in Figure 5, we succeeded in
the synthesis of iPP with broad isotacticity
distribution using the TiCl
3
/MgCl
2
cata-
lyst.
[9]
Four kinds of iPP with different
isotacticities were easily obtained from
the fractionation of this iPP by TREF.
The fraction ratios and molecular weights
are summarized in Table 4. The nomen-
clature of the fractionated iPP is as follows:
iPP91 denotes iPP with the pentad fraction
(mmmm) of ca. 91 mol%. All pentad frac-
tions of the iPPs are shown in Table 5.
The dependence of thermal oxidative
degradation on the isotacticity was carried
out with these iPPs. It is noticed here that
all of the thermal oxidations have been
Figure 8.
Arrhenius plots of
t
di
for thermal oxidative degradation of iPPs.
