15 “Polymer–Oxide” Micro-/Nanocomposites: Background and Promises
265
should be noted. First, we see that if an oxide is added, the shape of the ε / and
ε // curves changes. In fact, relative intensity of the ε / curves increases in the
range −125–25 ◦ C, and the ε // values increase in the whole temperature range.
Especially, it concerns the temperature range 25–125 ◦ C, where the ε // values in
the maximum of the curves increase four to six times. We can note that only (ε / ,
ε // ) value changes occur in the range 25–125 ◦ C, if EMF frequency or oxide content
increases and there is no (ε / , ε // ) curve shifts in this temperature range. In contrast, it
is easy to see that ε // curves in the range −125–25 ◦ C shift to the higher temperature
side when EMF frequency increases. So, we assume that two kinds of impact of
oxide particles on the surface MCC molecular groups take place, and their responses
on this influence are different. Obviously, some amount of water molecules,
hydroxyl groups, and ambient gases had been incorporated into MCC host as associated with the surface of oxide particles. There they bind to molecular groups on the
surface of MCC microfibrils that promote increasing of the dipole moment (polarizability) of the samples. As a result, ε // values increase when oxide is added (please
compare Fig. 15.9b and Fig. 15.9d, f, h).These changes manifested in the dielectric
permittivity behavior during first heating of the sample in the EMF of lower frequency. The next heating made under action of the higher EMF frequency removes
more water and some ambient gas molecules and leads to the decrease of the (ε / ,
ε // ) values. These changes noticeably revealed in the temperature range 25–125 ◦ C.
Described data correspond to, measured by us, the thermogravimetric analysis
(TGA) data. The TGA curves for the un-doped, C0 sample and C1 intersect at 25
and 125 ◦ C, while in the whole temperature range between these points, 25–125 ◦ C,
C0 sample curve is higher than C1 curve (Fig. 15.10a). The behavior of these curves
is different: first of them is convex and second is concave. So, the difference between
them is largest in the temperature range near 60–80 ◦ C. The TGA curves for C2
and C3 samples show similar temperature behavior, but difference between them
increases when temperature increases. In fact, the difference is near 0.3% at 25 ◦ C,
and it is near 0.6% when temperature rises up to 125 ◦ C. Thus, we can note that
difference between dependence for the C0 sample, which doesn’t contain oxide
component, and C1 sample, where oxide amount is minimal, is appreciable. The
dependences for C2 and C1 samples are close, while characteristics of the C3 sample
differ considerably from the C2 sample, in spite of the similar difference in the oxide
contents: about ten times in both cases.
The differential scanning calorimetry (DSC) curves (Fig. 15.10b) have demonstrated similar behavior for the C0, C2, and C3 samples up to temperature near
70 ◦ C, when difference has aroused between them. As a result, calorimetric
singularity is near 103, 92, and 98 ◦ C for the C0, C2, and C3 samples. A big
difference is observed between the DSC curve for C1 sample and other DSC curves.
Mentioned fact concerns both of the curve shape and singularity positions. The last
one is near 67 ◦ C for the C1 sample.
Thus, we can note that considerable difference between characteristics of the
C0 sample, which doesn’t contain oxide component, and C1 sample is obvious.
This difference can be regarded as predicable, as it reflects radical difference in
265
should be noted. First, we see that if an oxide is added, the shape of the ε / and
ε // curves changes. In fact, relative intensity of the ε / curves increases in the
range −125–25 ◦ C, and the ε // values increase in the whole temperature range.
Especially, it concerns the temperature range 25–125 ◦ C, where the ε // values in
the maximum of the curves increase four to six times. We can note that only (ε / ,
ε // ) value changes occur in the range 25–125 ◦ C, if EMF frequency or oxide content
increases and there is no (ε / , ε // ) curve shifts in this temperature range. In contrast, it
is easy to see that ε // curves in the range −125–25 ◦ C shift to the higher temperature
side when EMF frequency increases. So, we assume that two kinds of impact of
oxide particles on the surface MCC molecular groups take place, and their responses
on this influence are different. Obviously, some amount of water molecules,
hydroxyl groups, and ambient gases had been incorporated into MCC host as associated with the surface of oxide particles. There they bind to molecular groups on the
surface of MCC microfibrils that promote increasing of the dipole moment (polarizability) of the samples. As a result, ε // values increase when oxide is added (please
compare Fig. 15.9b and Fig. 15.9d, f, h).These changes manifested in the dielectric
permittivity behavior during first heating of the sample in the EMF of lower frequency. The next heating made under action of the higher EMF frequency removes
more water and some ambient gas molecules and leads to the decrease of the (ε / ,
ε // ) values. These changes noticeably revealed in the temperature range 25–125 ◦ C.
Described data correspond to, measured by us, the thermogravimetric analysis
(TGA) data. The TGA curves for the un-doped, C0 sample and C1 intersect at 25
and 125 ◦ C, while in the whole temperature range between these points, 25–125 ◦ C,
C0 sample curve is higher than C1 curve (Fig. 15.10a). The behavior of these curves
is different: first of them is convex and second is concave. So, the difference between
them is largest in the temperature range near 60–80 ◦ C. The TGA curves for C2
and C3 samples show similar temperature behavior, but difference between them
increases when temperature increases. In fact, the difference is near 0.3% at 25 ◦ C,
and it is near 0.6% when temperature rises up to 125 ◦ C. Thus, we can note that
difference between dependence for the C0 sample, which doesn’t contain oxide
component, and C1 sample, where oxide amount is minimal, is appreciable. The
dependences for C2 and C1 samples are close, while characteristics of the C3 sample
differ considerably from the C2 sample, in spite of the similar difference in the oxide
contents: about ten times in both cases.
The differential scanning calorimetry (DSC) curves (Fig. 15.10b) have demonstrated similar behavior for the C0, C2, and C3 samples up to temperature near
70 ◦ C, when difference has aroused between them. As a result, calorimetric
singularity is near 103, 92, and 98 ◦ C for the C0, C2, and C3 samples. A big
difference is observed between the DSC curve for C1 sample and other DSC curves.
Mentioned fact concerns both of the curve shape and singularity positions. The last
one is near 67 ◦ C for the C1 sample.
Thus, we can note that considerable difference between characteristics of the
C0 sample, which doesn’t contain oxide component, and C1 sample is obvious.
This difference can be regarded as predicable, as it reflects radical difference in