## 3 Results and Discussion
### Non-Isothermal Crystallization Behavior of P3 HBHrk--Effect of Nucleating Agents
#### 3.1.2 Effect of Nucleating Agents on Non-Isothermal Crystallization of P3 HBHHx  
The non-isothermal crystallization behavior of P3 HBHHx containing 0.5 wt% nucleating agents was investigated. The results are summarized in Table 2 and illustrated in Figure 2a,b. The incorporation of nucleating agents led to a significant increase in the crystallization temperature (\(T_{c}\)) compared to that of neat P3 HBHHx. Figure 1: DSC cooling curve (black) and 2 nd heating curve (red) of neat P3 HBHHx. The inset graph shows the expanded crystallization peak from the melt. The most pronounced improvements were observed for boron nitride (PHH_05 BN) and PHB (PHH_05 PHB), which raised \(T_{\rm c}\) from 36.4 \({}^{\circ}\)C (neat P3 HBHHx) to 84.1 \({}^{\circ}\)C and 81.9 \({}^{\circ}\)C, respectively. This substantial increase indicates that both additives effectively promote crystal formation during cooling. In addition, the crystallization enthalpy increased markedly from 8.9 J/g in neat P3 HBHHx to 59.5 J/g in the PHB-loaded sample. The absence of cold crystallization peaks during the second heating run further confirms that crystallization was completed during the cooling phase, leaving no residual amorphous regions to crystallize upon reheating. These findings suggest that both BN and PHB are highly effective in enhancing nucleation and accelerating the crystallization kinetics. The superior performance of BN and PHB can be attributed to their nucleation efficiency and compatibility with the P3 HBHHx matrix. BN possesses a highly crystalline and thermally conductive structure that promotes heterogeneous nucleation. Its high surface area and heat dissipation capacity may lower the nucleation barrier, thereby enabling faster crystal formation [22]. In contrast, PHB is chemically similar to P3 HBHHx and may facilitate epitaxial crystallization due to its structural compatibility, providing an efficient interface for chain alignment and crystal growth [35]. Talc and UFC also improved the crystallization behavior of P3 HBHHx, increasing \(T_{\rm c}\) to 66.5 \({}^{\circ}\)C and 58.9 \({}^{\circ}\)C, respectively. However, the presence of a cold crystallization peak in the PHH_05 Talc sample, along with its relatively low crystallization enthalpy (46.3 J/g), indicates incomplete crystallization. This suggests that while talc provides nucleation sites, its effectiveness may be limited by agglomeration or less favorable surface interactions. Although offering additional surface area, it contains hydroxyl groups that may interfere with the crystallization process, resulting in moderate performance [36; 37]. The addition of organic potassium salt (LAK) resulted in only a slight increase in \(T_{\rm c}\) to 45.6 \({}^{\circ}\)C. The limited shift in the crystallization temperature, along with the presence \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline
**Samples** & \(T_{\rm c}\) (\({}^{\circ}\)C) & \(\Delta H_{\rm c}\) (J/g) & \(T_{\rm g}\) (\({}^{\circ}\)C) & \(T_{\rm cc}\) (\({}^{\circ}\)C) & \(\Delta H_{\rm cc}\) (\({}^{\circ}\)C) & \(T_{\rm m1}\) (\({}^{\circ}\)C) & \(T_{\rm m2}\) (\({}^{\circ}\)C) & \(\Delta H_{\rm f}\) (J/g) \\ \hline P3 HBHHx & 36.4 & 8.9 & 1.4 & 44.7 & 44.6 & 130.0 & 150.2 & 55.6 \\ PHH\_05 LAK & 45.6 & 18.3 & 1.4 & 45.5 & 38.4 & 129.8 & 149.5 & 58.0 \\ PHH\_05 UFC & 58.9 & 48.5 & 4.8 & - & - & 132.1 & 150.2 & 56.5 \\ PHH\_05 Talc & 66.5 & 46.3 & 3.7 & 45.3 & 0.8 & 133.2 & 149.9 & 49.7 \\ PHH\_05 PHB & 81.9 & 59.5 & 4.4 & - & - & 138.1 & 152.7 & 60.0 \\ PHH\_05 BN & 84.1 & 56.5 & 3.3 & - & - & 136.6 & 150.7 & 56.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: DSC summarized the data of P3 HBHHx with 0.5 wt% nucleating agents obtained from non-isothermal processes. Figure 2: DSC traces of P3 HBHHx with various nucleating agents during cooling (**a**) and second heating runs (**b**). The dashed sphere highlights the shifted melting peaks. of cold crystallization during reheating, indicates that LAK is less effective in promoting crystallization from the melt.