The effect of calcium salt of carboxylic acid on the crystallization behavior and mechanical properties of Polybutylene succinate

Polybutylene succinate (PBS) has garnered significant attention as a novel biodegradable plastic due to its superior thermal resistance and processability. However, the slow crystallization rate and poor mechanical properties of PBS remain challenges, which can be significantly improved by the addition of nucleating agents. Currently, effective nucleating agents for PBS are scarce, making the search for efficient PBS nucleating agents crucial for enhancing its performance. In this study, various calcium carboxylate nucleating agents were synthesized, and their structures were characterized via Fourier Transform Infrared Spectroscopy (FTIR). The crystalline behavior of the nucleated PBS was analyzed using differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The results indicate that among the synthesized nucleating agents, calcium hexahydrophthalate (CaHHPA) exhibited the best performance, significantly increasing the crystallization temperature of PBS by over 10 °C, accelerating crystallization rates, and substantially reducing crystal size. Meanwhile, the addition of CaHHPA effectively enhanced the impact strength from 7.7 kJ/m² to 9.2 kJ/m² and increased the flexural modulus from 638.1 MPa to 708.4 MPa. Furthermore, the isothermal crystallization kinetics of PBS were analyzed using the Avrami equation, and it was found that the addition of nucleating agents did not alter the crystallization mechanism of PBS. In conclusion, CaHHPA has proven to be a novel and effective nucleating agent for PBS.