DSC is most commonly used to determine the thermal transition
temperatures, such as glass transitions, melting, crosslinking,
and decomposition. However, DSC measures only
the total heat flow and the sum of all thermal transitions in
the sample. The DSC measurement of PANI/DBSA–PVA
blends under a N2 atmosphere is shown in Fig. 4 and summarised
in Table 3, which reveals a broad endothermic peak
in the range of 100–150 _C due to the elimination of water
and impurities, which is also found in the TGA thermogram.
The glass transition temperature of PANI is 80 _C. PANI/
DBSA–PVA blends exhibit only a single glass transition temperature,
which gradually decreases with increases in the
PANI content in the blends until a PANI content of 6% is
reached, and then starts to increase again with the PANI content.
Generally, the shift trend of Tg can be considered as the
index of miscibility of polymer blends.