## 3 Results and Discussion
### Structural Comparison of P3 HBHrk with Different Nucleating Agents
#### 3.2.3 Influence of Nucleating Agents on the Thermal Stability of P3 HBHHx  
Figure 8 presents the results of TGA, showing the remaining mass percentage of each sample as a function of temperature, along with the corresponding derivative thermogravimetric (DTG) curves. The temperatures at which 5%, 50%, and 90% mass loss occurred  
Figure 6: FTIR spectra of P3 HBHHx samples loaded with different nucleating agents. Figure 7: Weight and number average molecular weights of neat P3 HBHHx and the different nucleated samples. (\(T_{5\%}\), \(T_{50\%}\), and \(T_{90\%}\)), the temperature at the maximum rate of mass loss (\(T_{\max}\)), and the residual mass at 450 \({}^{\circ}\)C are summarized in Table 4.  
According to the results, neat P3 HBHHx exhibited \(T_{5\%}\) of 246.9 \({}^{\circ}\)C. Samples containing PHB (PHH_05 PHB), LAK (PHH_05 LAK), and 0.5 wt% talc (PHH_05 Talc) showed nearly identical \(T_{5\%}\) values around 246 \({}^{\circ}\)C, indicating that these nucleating agents did not significantly affect the initial thermal resistance of the material. A slight increase to 247.9 \({}^{\circ}\)C was observed for PHH_2 Talc, suggesting a modest improvement in thermal stability at a higher talc content. In contrast, PHH_05 BN and PHH_05 UFC exhibited significantly lower \(T_{5\%}\) values of 236.1 \({}^{\circ}\)C and 236.3 \({}^{\circ}\)C, respectively, indicating a reduction in thermal stability. A similar trend was observed for \(T_{50\%}\) and \(T_{90\%}\), reinforcing the observation that these two additives accelerated degradation. This behavior is likely associated with the specific interactions between the nucleating agents and the polymer matrix. Boron nitride, known for its high thermal conductivity, may enhance heat transfer within the material, leading to localized heating and an earlier onset of decomposition [40]. Similarly, ultrafine cellulose introduces numerous hydroxyl groups that can act as additional sites for thermal degradation. These groups are prone to hydrolysis, potentially accelerating the degradation process by initiating the earlier thermal breakdown of the polymer chains [36]. \(T_{\max}\) trends were largely consistent with the \(T_{5\%}\) results, with PHH_05 BN and PHH_05 UFC exhibiting the lowest \(T_{\max}\) values (258.3 \({}^{\circ}\)C and 261.1 \({}^{\circ}\)C, respectively), indicating that these samples underwent the most rapid decomposition during thermal \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \(T_{\max}\) & \(T_{5\%}\) & \(T_{50\%}\) & \(T_{90\%}\) & **Residue at 450** \\  & (\({}^{\circ}\)C) & (\({}^{\circ}\)C) & (\({}^{\circ}\)C) & (\({}^{\circ}\)C) & \({}^{\circ}\)C (wt\%) \\ \hline P3 HBHfx & 275.7 & 246.9 & 269.1 & 276.7 & 0 \\ PHH_05 LAK & 273.5 & 246.8 & 267.3 & 275.1 & 0.57 \\ PHH\_05 UFC & 261.1 & 236.3 & 255.4 & 263.6 & 0.50 \\ PHH\_05 PHB & 273.6 & 247.1 & 267.8 & 275.3 & 0.52 \\ PHH\_05 BN & 258.3 & 236.1 & 255.2 & 263.8 & 0.58 \\ PHH\_05 Talc & 271.4 & 246.7 & 266.9 & 274.6 & 0.53 \\ PHH\_2 Talc & 279.5 & 247.9 & 264.3 & 281.7 & 1.76 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Thermogravimetric parameters of P3 HBHfx and the nucleated samples. Figure 8: Thermal degradation behavior of P3 HBHfx with different nucleating agents: (**a**) Remaining mass percentage as a function of temperature, and (**b**) Derivative TGA curves showing the peak temperature at the maximum rate of mass loss. The black curve represents the sample with the highest thermal stability, the red curves correspond to samples with lower thermal stability, and the blue curves indicate samples with thermal stability similar to neat P3 HBHfx. breakdown. In contrast, PHH_2 Talc exhibited the highest \(T_{\text{max}}\) of 279.5 \({}^{\circ}\)C. This behavior is consistent with the enhanced crystallinity and thermal resistance observed for this sample. This improvement is likely related to the increased crystallinity observed with 2 wt% talc (Figure 3), as crystalline regions are inherently more thermally stable than amorphous ones.