## 3 Results and Discussion
### Non-Isothermal Crystallization Behavior of P3 HBHrk--Effect of Nucleating Agents
#### 3.1.4 Nucleation Efficiency  
As shown in Figure 4, self-nucleation experiments revealed that fully crystallized P3 HBHHx exhibits distinct crystallization behavior when reheated to different self-nucleation temperatures (\(T_{\text{s}}\)). At \(T_{s}\) = 145 \({}^{\circ}\)C, no crystallization occurred during the subsequent cooling phase. Since melting did not occur at this temperature, the original crystalline structures remained intact, and recrystallization was not initiated. Figure 4: DSC temprograms of self-nucleated P3 HBHHx at various self-nucleation temperatures (\(T_{\text{s}}\)), showing the determination of \(T_{\text{c}}^{\text{min}}\) and \(T_{\text{c}}^{\text{max}}\). Figure 3: DSC cooling and 2 nd heating runs of P3 HBHHx with different talc contents. The inset graph shows an expanded zone of cold crystallization of P3 HBHHx with 0.5 wt% talc. When \(T_{\rm s}\) increased to 150 \({}^{\circ}\)C, partial melting occurred, leaving some crystalline domains intact. These residual structures acted as nucleation sites, resulting in rapid crystallization during cooling. Under these conditions, the crystallization temperature was recorded as \(T_{\rm c}^{\rm max}\) = 127.7 \({}^{\circ}\)C for neat P3 HBHHx. As \(T_{\rm s}\) increased further, the crystallization temperature progressively decreased due to the melting of additional crystalline domains. At \(T_{\rm s}\) = 170 \({}^{\circ}\)C, all nuclei completely melted, leaving no residual sites for nucleation. In this case, the crystallization temperature was identified as \(T_{\rm c}^{\rm min}\) = 54.5 \({}^{\circ}\)C. It is important to note that in a previous non-isothermal crystallization study, the crystallization temperature of neat P3 HBHHx was reported as 36.4 \({}^{\circ}\)C under conditions where the material had also been fully melted. This difference can be attributed to the effect of the cooling rate on the crystallization behavior. At slower rates, such as 5 \({}^{\circ}\)C/min, the polymer chains have more time to align and form crystalline regions, resulting in a higher \(T_{\rm c}\). In contrast, faster cooling rates, such as 10 \({}^{\circ}\)C/min, reduce the time available for nucleation and crystal growth, leading to a lower \(T_{\rm c}\). The nucleation efficiency (% _NE_) of each nucleating agent was quantified using Equation (1). The results are summarized in Table 3 and Figure 5. The NE results revealed significant differences in the performance of the tested nucleating agents, highlighting their varying abilities to enhance the crystallization behavior of P3 HBHHx. PHH_05 BN and PHH_05 PHB exhibited the highest % _NE_ values of 46.2% and 42.8%, respectively. These results demonstrate their strong ability to promote nucleation and  
Figure 5: Nucleation efficiency (NE) of different nucleating agents in P3 HBHHx. \begin{table}
\begin{tabular}{c c c} \hline  & \(T_{\rm c}\) (\({}^{\circ}\)C) \({}^{\rm a}\) & **NE (\%) \({}^{\rm b}\)** \\ \hline P3 HBHHx & 54.5 & - \\ PHH\_05 LAK & 57.0 & 3.4 \\ PHH\_05 UFC & 68.3 & 18.9 \\ PHH\_05 Talc & 76.9 & 30.7 \\ PHH\_2 Talc & 83.9 & 40.2 \\ PHH\_05 PHB & 85.8 & 42.8 \\ PHH\_05 BN & 88.3 & 46.2 \\ \hline \end{tabular} \({}^{\rm a}\) Determined from a cooling run at 5 \({}^{\circ}\)C/min. \({}^{\rm b}\) Calculated using Equation (1).  
\end{table} 
Table 3: Crystallization temperature of P3 HBHHx with different nucleating agents at a cooling rate of 5 \({}^{\circ}\)C/min and corresponding nucleation efficiency calculated from Equation (1). significantly increase the number of effective crystallization sites during cooling. Their high efficiency suggests that BN and PHB facilitate early-stage crystal formation, allowing P3 HBHrk crystallization to occur more rapidly and uniformly. The effectiveness of BN can be attributed to its high surface area, thermal conductivity, and stable crystalline structure, which favor heterogeneous nucleation.