Non-isothermal crystallization behaviors and spherulitic morphology of poly(lactic acid) nucleated by a novel nucleating agent

The effect of cadmium phenylmalonate (PMA-Cd) as a novel nucleating agent on the crystallization behaviors and spherulitic morphology of poly(lactic acid) (PLA) as well as non-isothermal crystallization kinetics of the nucleated PLA were studied by means of differential scanning calorimetry and polarized light microscopy. The results showed that PMA-Cd served as an effective nucleating agent to accelerate the crystallization rate of PLA. The presence of PMA-Cd significantly increased the number and decreased the size of the spherulites. The non-isothermal crystallization kinetics of the nucleated PLA was well described by Mo's model. The activation energies (Delta E) of non-isothermal crystallization were calculated by Kissinger's method. The crystallization rate of PLA/0.5 % PMA-Cd sample was faster than that of PLA/0.2 % PMA-Cd sample, while the Delta E of the former was greater than that of the latter. The nucleation mechanism between PMA-Cd and PLA was satisfactorily explained by dimensional lattice-matching criterion.