Influence of functional group structures in nucleating agents on the crystallization behavior of poly(ethylene terephthalate)

Nucleating agents are crucial for modifying semi-crystalline polymers, but the impact of different end-group structures on crystallization behavior remains unclear. This study synthesized succinic dihydrazide nucleating agents with various end groups (methyl, ethyl, and tert -butyl) for PET composite materials. The tert -butyl-terminated nucleating agent showed the best performance, increasing the crystallization peak temperature to 203.8°C, crystallinity to 27.3%, and reducing half-crystallization time to 2.8 min at 220°C. It also enhanced the impact strength to 47.2 kJ·m −2 and flexural modulus to 2623 MPa, while improving Vicat softening temperature and heat distortion temperature by 41 and 8°C, respectively. The results from FTIR and Raman Spectroscopy indicate that the interactions between the end groups of the nucleating agent and the C  H bonds in the PET structure, the π–π interactions between the nucleating agent and the PET molecular structure, as well as the modulation of the PET chain conformation by the nucleating agent, are the primary factors contributing to the enhanced crystallinity of PET. This study provides a new approach for designing efficient nucleating agents for high-performance materials.