132
L. V. Karabanova et al.
Fig. 8.7 Isotherms of
dichloromethane vapour
sorption at 20 ◦ C by samples:
1, polyurethane; 2,
nanocomposite with 0.1%
MWCNT-red; 3,
nanocomposite with 0.25%
MWCNT-red; and 4,
MWCNT-red
the coincidence of sorption isotherms for nanocomposites with different amounts of
nanofiller could mean the worst distribution of MWCNT-red in the polymer matrix
(relatively less of boundary layers in the nanocomposite with increasing amount of
nanofiller).
The using of the thermodynamic methods and calculations based on experimental
data of vapour sorption of dichloromethane by nanocomposites samples allowed
us to estimate a number of characteristics of the systems, namely, the free energy
of interaction of polymers with solid surfaces. In [37] the method calculation
of thermodynamic parameters of the polymer-polymer interaction was proposed.
For this, the approach based on the fundamental assumptions of independence of
thermodynamics enthalpy and free energy of the system from the way of the process
was used [37]. In [38, 39] this approach was applied for polymer-filler systems.
Under this approach, we can calculate the parameters of interaction of polymer
with a filler when parameters of the interaction of each of them and their mixtures
with fluid are known. Based on isotherms of sorption, the change of the partial
free energy of dichloromethane μ 1 was calculated using eq. (8.1). The change
in the partial free energy of individual polymer and filled systems under sorption
process 2 was determined in accordance with the Gibbs-Duhem Eq. (8.2). Free
energy of mixing of individual polymer and nanocomposites with solvent m was
determined in accordance with Eq. (8.4).
In Fig. 8.8 the calculated values m for neat polyurethane, for nanocomposites and for nanofillers MWCNT-ox and MWCNT-red are shown. It is evident
that all the systems under investigation PU-dichloromethane, nanocompositesdichloromethane and nanofillers-dichloromethane are thermodynamically stable
(d 2 m /dW 2
2 > 0). Although the affinity of dichloromethane to PU (Fig. 8.8, curve
1) is the highest.
L. V. Karabanova et al.
Fig. 8.7 Isotherms of
dichloromethane vapour
sorption at 20 ◦ C by samples:
1, polyurethane; 2,
nanocomposite with 0.1%
MWCNT-red; 3,
nanocomposite with 0.25%
MWCNT-red; and 4,
MWCNT-red
the coincidence of sorption isotherms for nanocomposites with different amounts of
nanofiller could mean the worst distribution of MWCNT-red in the polymer matrix
(relatively less of boundary layers in the nanocomposite with increasing amount of
nanofiller).
The using of the thermodynamic methods and calculations based on experimental
data of vapour sorption of dichloromethane by nanocomposites samples allowed
us to estimate a number of characteristics of the systems, namely, the free energy
of interaction of polymers with solid surfaces. In [37] the method calculation
of thermodynamic parameters of the polymer-polymer interaction was proposed.
For this, the approach based on the fundamental assumptions of independence of
thermodynamics enthalpy and free energy of the system from the way of the process
was used [37]. In [38, 39] this approach was applied for polymer-filler systems.
Under this approach, we can calculate the parameters of interaction of polymer
with a filler when parameters of the interaction of each of them and their mixtures
with fluid are known. Based on isotherms of sorption, the change of the partial
free energy of dichloromethane μ 1 was calculated using eq. (8.1). The change
in the partial free energy of individual polymer and filled systems under sorption
process 2 was determined in accordance with the Gibbs-Duhem Eq. (8.2). Free
energy of mixing of individual polymer and nanocomposites with solvent m was
determined in accordance with Eq. (8.4).
In Fig. 8.8 the calculated values m for neat polyurethane, for nanocomposites and for nanofillers MWCNT-ox and MWCNT-red are shown. It is evident
that all the systems under investigation PU-dichloromethane, nanocompositesdichloromethane and nanofillers-dichloromethane are thermodynamically stable
(d 2 m /dW 2
2 > 0). Although the affinity of dichloromethane to PU (Fig. 8.8, curve
1) is the highest.