Development of a Biomass Furan-Hydrazide Nucleating Agent of Poly(l-lactide) and Its Application for Biaxial-Oriented Films with Enhanced Performance

The application of poly( l -lactide) (PLLA) is constrained by its inherently slow crystallization rate, resulting in limited heat resistance. The incorporation of nucleating agents (NAs) presents a promising solution to promote PLLA’s crystallization. In this study, we successfully utilized furan-based biomass feedstock to develop an organic NA, N ′ 1, N ′ 10 -di(furan-2-carbonyl) decanedihydrazide (DFDH), for PLLA. Impressively, even with a minimal addition of 0.1% of DFDH, it had a profound impact on PLLA crystallization, yielding a crystallization temperature of 124.3 °C and a crystallinity of 42.7%. Furthermore, the isothermal crystallization time of the PLLA compounds consistently decreased, and both crystallization temperature and degree of crystallization increased with the additive amount. Through a combination of temperature-dependent Fourier-transform infrared analysis and molecular docking calculations, it is elucidated that DFDH directs PLLA chains toward the optimal gt conformation via dipole–dipole interactions with the carbonyl group of PLLA while maintaining chain spacing aligned with the cell constant of the α-crystalline structure. This mechanistic insight offers valuable clarity on nucleation regulation. Additionally, after the synchronized biaxial stretching of PLLA containing 0.3% DFDH, notable improvements were observed in the toughness and optical properties of PLLA films, especially at lower stretching rates. These findings not only hold theoretical significance for the development of biobased PLLA nucleating agents but also present practical promise for their application in biaxial stretching processes.