Chemistry Reference
In-Depth Information
Atomic force microscopy is considered one of the most perspective
methods for studying polymer blends is because this method allows to
clearly define the phase boundary and its scale. Polymer identification was
performed by controlling the interaction of the probe with the sample sur-
face at different points. When approaching the surface of the cantilever is
deflected downward (to the sample) due to attractive forces until the probe
comes into contact with the sample. When the probe is withdrawn from
the studied surface, a hysteresis is observed, associated with the adhe-
sive forces. Adhesion forces between the probe and the sample are forcing
them to remain in contact, which causes the cantilever to bend. Phase of
the polymers were very clearly identified by mapping curves “approach-
removal” of the probe.
Probable range of the phase inversion is an important characteristic
for mixed biodegradable composites. This allows from a practical point of
view to establish the minimum concentration of PHB (at which a continu-
ous phase is formed) for intensive biodegradation as microorganisms must
be able to penetrate deep into the mixed composite. When compared with
the atomic force microscopy of samples with different proportions of the
components was found that in investigated materials continuous matrix
formation occurs when PHB content in the mixture of about 40-50% by
weight. The results of atomic force microscopy for the composition ratio
of PHB-PIB 50:50 shown in Fig. 4.2.
FIGURE 4.2
(Continued)
