. The general trend is increase of storage modulus
with increase in peroxide content with exception of sample
0.7 and temperatures above 180 C.
storage modulus
Fig. 11. Storage modulus from DMA as a function of peroxide content
measured at various temperatures.
Fig. 9 illustrates the dependence of gel content on peroxide
content of the cross-linked samples. It can be seen
and samples with 0.2 and 0.3 wt.% of peroxide. While the
pure EOC survived the DMA test only till 80 C the sample
with 0.3 wt.% of peroxide ran till 160 C. Even though the
network was not fully created there is a big change in
the storage modulus curve. The 0.4–0.6 wt.% of peroxide
curves have very similar trend and they are close to each
other; just there is a small increase with increase in peroxide
level. 0.7 curve has highest value of storage modulus
till 180 C, then it is rapidly decreasing and has lower value
than the 0.6 curve. In the 180–200 C temperature range
the degradation of 0.7 samples is decreasing the mechanical
properties. The effect of peroxide content on storage
modulus at various temperatures is very nicely visible on
Fi
9 illustrates the dependence of gel content on peroxide
content of the cross-linked samples. It can be seen
that as the peroxide content increases, gel content also increases
with an exception in the case of 0.2 and 0.3 wt.% of
peroxide. In the case of 0.2 and 0.3, there was no insoluble
fraction left out after extracting with xylene, which implies
that the cross-linking reaction lead only to longer molecules
but the network was not created. There is a sharp increase
(0–54%) in gel content from 0.3 to 0.4 wt.% of
peroxide. Then, in the case of 0.5, 0.6 and 0.7, gel content
gradually increases with increasing peroxide content. Increase
in gel content is due to increase in cross-link network
and thus cross-link density
Fig. 10 shows storage modulus as a function of temperature.
While for samples with 0.2 and 0.3 wt.% of peroxide
the gel content was zero (no difference from pure EOC), the
DMA analysis revealed big difference between pure EOC
and samples with 0.2 and 0.3 wt.% of peroxide. While the
pure EOC survived the DMA test only till 80 C the sample
with 0.3 wt.% of peroxide ran till 160 C. Even though the
network was not fully created there is a big change in
the storage modulus curve. The 0.4–0.6 wt.% of peroxide
curves have very similar trend and they are close to each
other; just there is a small increase with increase in peroxide
level. 0.7 curve has highest value of storage modulus
till 180 C, then it is rapidly decreasing and has lower value
than the 0.6 curve. In the 180–200 C temperature range
the degradation of 0.7 samples is decreasing the mechanical
properties. The effect of peroxide content on storage
modulus at various temperatures is very nicely visible on
Fi
Fig. 11. The general trend is increase of storage modulus
with increase in peroxide content with exception of sample
0.7 and temperatures above 180 C.