# Formation of Conductive Networks in Polysulfone Filled with Graphite-Derived Materials
## 3 Results and Discussion
### Composites Density and Ponsity  
We tested the density of the composite using hydrostatic techniques to investigate the effect of increasing filler content on the density and thermal conductivity of the composite.  
As previously stated, we measured the density of the samples acquired here. We can observe how the density grew as the filler material increased.  
We may conclude that the composite preparation conditions, particularly the applied pressure in sample preparation technology, had a significant impact on the density of the composite, allowing for better thermal conductivity values and higher electrical conductivity in the composites. When graphite particles are put into the matrix, they create agglomerates that are randomly dispersed throughout the matrix, influencing the reported characteristics. Figure 6 depicts the change in heat conductivity of the composite as its density changes.  
By combining carbon black and natural graphite as fillers, both elements contribute to the composite's decreased heat conductivity. These fillers disturb the thermal routes inside the matrix, lowering the overall rate of heat transmission. The magnitude of the drop, however, is determined by parameters such as filler content, dispersion, and matrix properties. In the case of using carbon black with artificial graphite as fillers, we can see the enhancement in thermal conductivity compared to using just AG as filler, which can be shown in Figure 7.  
Figure 6: The dependence of thermal conductivity on density of PSU-based composites filled with NG and AG.  
Figure 7: The dependence of thermal conductivity on density of PSU-based composites filled with NG + CB and AG + CB.  
Two different series of samples of the same fillers content was used in the measurements; thus, two experimental points were given for every composite.  
The porosity of the composite including AG and NG as fillers increased as the filler content increased as shown in Figure 8. Such increase is associated with the formation of filler agglomerates in the polymer matrix, which grow as the filler concentration increases. An uneven distribution of carbon black and graphite fillers might result in increased porosity in some places. Proper filler dispersion and homogeneous distribution can assist to improve porosity throughout the composite. We may also assume that reducing the compaction pressure during compression allows for the formation of voids or pores, increasing the total porosity of the composite.  
The results of composite porosity using CB as a filler are significantly lower than the results of using different types of graphite as fillers. Carbon black dispersion inside the matrix is critical to preventing agglomeration and ensuring uniform distribution. The use of effective mixing procedures and proper processing settings can aid in achieving optimal dispersion and minimizing vacuum formation.  
The viscosity of the matrix material can be adjusted to limit the possibility of porosity development. The use of CB as a filler boosts the composite's viscosity and provides improved flow and wetting of the carbon black particles, allowing for compact packing and decreased porosity.