The thermogravimetry (TG) curves (Fig. 2) show that the mass
change of modified and unmodified graphite is obviously different. For
the sample 0#, as temperature increases, 1.11% of mass is lost, which
is probably caused by evaporation of the residual water in the compound.
The mass loss for the modified graphite is much higher. It is
surely that the substances on the surface of graphite make substantial
contributions to the loss.Among the difference between modified and unmodified graphite,
the mass change between different modified graphite filled composites
is also different. The mass change of 2# is larger than that of 1#, that of
4# is higher than of 3#, that of 6# is larger than of 5#, and the mass
change of 8# is greater than that of 7#. The different ratios between acrylate
polymerization emulsion and graphite lead to the results. As is shown
in Table 1, the ratio of the former is larger than that of the latter. The larger
ratio is accompanied by more polyacrylate coating the graphite. This
results in a greater mass change.
The initial thermal decomposition temperature of polyacrylate
can also be seen in Fig. 2. It can be inferred that the ratio between
monomers is the main factor. As is depicted, the initial thermal
decomposition temperature of 1# and 2 # is about 380 °C, 3# and
4# about 370 °C, 5# and 6# about 365 °C, and 7# and 8# about
361 °C. One of the possible reasons is that the ratio between monomers
affects the structure and properties of the polyacrylate. Besides,
the higher the percentage of the soft monomer BA is, the longer the
molecular chain of polyacrylate is. The longer molecular chain will
reduce the strength and adhesion properties of the polyacrylate,
and thus the initial thermal decomposition temperature decreases.
According to Table 1, the percentage of BA in monomers of 1# and
2# is the lowest, while 7# and 8# have the highest BA percentage.
Therefore, the initial thermal decomposition temperature of 1# and
2# is the highest, while that of 7# and 8# is the lowest. In addition,
the ratio between monomers also affects the interaction and aggregation
of polyacrylate particles. It will also have some effect on the
initial decomposition temperature of the polymer.