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 °C compared with that of pure iPP. Simultaneously, EL-Zn, EL-Ba and EL-Ca all had strong β -crystal induction ability to iPP. Especially, when the addition amount of EL-Zn in iPP was 0.20 wt%, the relative β -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.