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The effects of dioctyl phthalate (DOP) on performances of poly(L-lactic acid) (PLLA) were investigated in detail using optical depolarizer, X-ray diffraction, melt index instrument, and electronic tensile tester. Crystallization performance showed that the half time of overall PLLA crystallization t1/2 decreased with increasing of crystallization temperature (80°C to 105°C), but the t1/2 of PLLA/DOP composites firstly decreased and then increased, and t1/2 of PLLA/DOP exhibited minimum value at 85°C. Compared to neat PLLA, 20%DOP made the t1/2 decrease from 7258.3 s to 265.4 s. X-ray diffraction experiment further confirmed that DOP could accelerate the crystallization of PLLA. The fluidity of PLLA/DOP composites indicated that the melt mass flow rate firstly decreased and then greatly increased with increasing of DOP content. The mechanical performance showed that DOP could improve the general mechanical performance, and the elongation at break of PLLA/25%DOP was about 30 times longer than that of neat PLLA.

N,N,N′-Tris(benzoyl) trimesic acid hydrazide (TTAD), as a novel nucleating agent of poly(L-lactic acid) (PLLA), was synthesized and characterized by FT-IR and 1H NMR. The crystallization, melting behavior, and thermal stability of PLLA induced by TTAD were investigated through DSC, TGA, depolarized-light intensity measurement, and so forth. The crystallization behavior indicated that the presence of TTAD accelerated the overall PLLA crystallization. Compared to neat PLLA, the crystallization onset temperature of PLLA/1%TTAD increased from 101.36°C to 125.26°C, the melt-crystallization peak temperature increased from 94.49°C to 117.56°C, crystallization enthalpy increased from 0.1023 J·g−1 to 33.44 J·g−1 at a cooling rate of 1°C/min from melt, and the crystallization half-time of PLLA/TTAD decreased from 2997.2 s to 108.9 s at 110°C. Moreover, the nonisothermal crystallization measurements also indicated that the crystallization peak became wider and shifted to a lower temperature with increasing cooling rate. With the presence of TTAD, the melting behavior of PLLA was affected significantly, and a double-melting peak occurred due to melting-recrystallization. Thermal stability research showed that there existed one degradation stage of PLLA and PLLA/TTAD samples, and the thermal degradation temperature of PLLA/TTAD decreased compared to neat PLLA.