FIGURE 6 (a) Water contact angle, (b) Water
absorption of PP and SCG/PP composites
3.3.3 Thermal stability
To study the influence of SCG under different heat treatment conditions
on the thermal stability of PP composite, the thermal decomposition
curve of the composite was tested, as shown in Figure 7. The initial
thermal decomposition temperature of PP is 385 °C. After adding filler,
the thermal stability of PP decreases, which is manifested as the
advance of the initial thermal decomposition temperature. The thermal
decomposition trend was similar after the addition of fillers, and the
first stage of thermal decomposition was attributed to the partial
decomposition of SCG. Compared with the SCG/PP composite, the thermal
stability of the NSCG/PP and ASCG/PP composite are slightly improved,
and the initial thermal decomposition temperature is increased from 265
℃ to 280 ℃. After heat treatment, the O/C ratio of SCG decreases and has
stronger thermal stability (Leow et al., 2021). However, the thermal
stability of SCG/PP composites treated in different atmospheres is
similar, indicating that SCG fillers treated in different atmospheres
have little effect on the thermal stability of PP. The results of the
specific thermogravimetric values are summarized in Table 1.