Effects of self-assembled nucleating agent on the crystallization behavior, thermal properties, and mechanical properties of polylactic acid

Polylactic acid (PLA) is a biodegradable polyester, but its low crystallization rate and excessive embrittlement limit its application. Decanedioic acid 1,10-bis (2-benzoylhydrazide) (TMC-300) as an effective nucleating agent of PLA will induce PLA epitaxial crystallization and improve the crystallization rate of PLA. This article studied the promoting behavior of TMC-300 with different contents in composite systems on PLA crystallization. The results showed that with the increase of TMC-300 content, the crystallinity can be significantly increased, up to 22 times, and t(1/2) significantly decreases. Meanwhile, with the addition of TMC-300, the typical spherical crystal morphology of PLA gradually became attached to TMC-300 fibrous crystal morphology. In terms of mechanical properties, the tensile strength reached its maximum at 0.5 wt% of TMC-300 content, increasing from 60.60 MPa (PLA) to 74.59 MPa (0.5-TMC-300), an increase of 23.09%. At this time, due to the reduction in spherical crystal size, the elongation at break also increased significantly. However, the thermal stability of PLA composites deteriorated with the increase of nucleating agent content due to the low thermal decomposition temperature of TMC-300 itself, and the T-max decreased from 372 degrees C (PLA) to 353 degrees C (5-TMC-300), a decrease of 19 degrees C.