Effect of a novel bio-based β-nucleating agent on the properties of isotactic polypropylene

This study reported a series of esterified lignin metal salts (EL-M, M = Na, Mg, Ca, Ba, Zn) derived from lignin as nucleating agents, which were used in isotactic polypropylene (iPP). The crystallization and melting behavior and mechanical properties of iPP/EL-M composites were studied. The results of differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) revealed that the crystallization temperature of iPP/EL-M composites increased by 5 to 8 degrees C compared with that of pure iPP. Simultaneously, EL-Zn, EL-Ba and EL-Ca all had strong beta-crystal induction ability to iPP. Especially, when the addition amount of EL-Zn in iPP was 0.20 wt%, the relative beta-content of iPP/EL-Zn reached up to 0.9277, and it was basically not affected by the cooling rate, indicating that EL-Zn was extremely active, selective and stable for iPP. For the vantage, the results of mechanical properties and SEM revealed that EL-Zn, EL-Ba or EL-Ca could improve the toughness of iPP to a certain extent.

Automated summary

The study showed that esterified lignin metal salts can serve as effective nucleating agents for isotactic polypropylene (iPP), resulting in increased crystallization temperature and improved toughness. Among them, EL-Zn exhibited strong beta-crystal induction ability to iPP, with potential applications in enhancing the mechanical properties of iPP composites.