Synthesis, Geometry Structure and Properties of

In this study, N, N’-carbonic bis(piperonylic acid) dihydrazide (BPACH) was synthesized to broaden the category of piperonylic acid derivative and evaluate its influences on the thermal properties of poly(L-lactic acid) (PLLA). The geometry optimization of BPACH showed that the highest occupied molecular orbital mainly focused on the formed amide group and carbonic dihydrazide, whereas the lowest unoccupied molecular orbital mainly focused on the piperonylic acid, and the orbital energy gap was 0.10418 eV. The differences in melt-crystallization processes of the neat PLLA and PLLA/BPACH samples indicated that the BPACH could provide the effective nucleation site to accelerate the crystallization of PLLA, but the crystallization accelerating effect was still further improved compared to some reported nucleating agents. The melting behaviors of PLLA/BPACH samples after crystallization depended on the crystallization temperatures and heating rates; additionally, the melting processes could also effectively reflect the previous crystallization behaviors