Chemistry Reference
In-Depth Information
FIGURE 4.4
Changes in the glass transition temperature of phase PHB.
The glass transition temperature change deserves attention because is a
sharp jump in the of PHB content of 50-60% by weight. This phenomenon
may also be due to the probable phase inversion (previously established by
microscopy methods) at said ratio of the components. Continuous struc-
ture more rigid of PHB has a higher glass transition temperature than the
individual inclusions of thermoplastic material, isolated from each other
by a continuous matrix of PIB. Thus, as a result of studies on the structure
of compositions of PHB-PIB was confirmed formation of heterogeneous
two-phase systems. For biodegradable polymer compositions it may be
advantage, because this system is more susceptible to external influences
destructive.
However, for practical use of PHB-PIB compositions is necessary to
evaluate the possibility of processing these materials into finished prod-
ucts. As most polymer blends are processed by melting them, investiga-
tions of rheological properties of these compositions are of great scientific
and practical interest. Information about the structure of composition that
can be obtained on the basis of rheological investigation is the level of
intermolecular interactions, the degree of macromolecules ordering, the
