Non-isothermal crystallization kinetics and spherulitic morphology of nucleated poly (lactic acid): effect of dilithium cis-4-cyclohexene-1,2-dicarboxylate as a novel and efficient nucleating agent

The effect of dilithium cis-4-cyclohexene-1,2-dicarboxylate (CHDA-Li) as a novel and efficient 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 was studied by means of differential scanning calorimetry and polarized light microscopy. The results show that CHDA-Li serves as a good nucleating agent to accelerate the crystallization rate of PLA. The nucleation ability of CHDA-Li is superior to octamethylenedicarboxylic dibenzoylhydrazide. With the incorporation of CHDA-Li, the number of the spherulites increases, and the size decreases significantly. The non-isothermal crystallization kinetics of the nucleated PLA can be well described by Jeziorny's and Mo's models. The activation energies (E) of non-isothermal crystallization were calculated by Kissinger's and Friedman's methods. The crystallization rate of PLA/0.5wt% CHDA-Li sample is faster than that of PLA/0.2wt% CHDA-Li sample, while the E of the former is lower than that of the latter. Copyright (c) 2015 John Wiley & Sons, Ltd.