The nucleation effect and thermal behavior of poly(l-lactic acid) in the presence of a bisamides compound

The nucleation effect and thermal behavior of bisamides compound (N, N'-Bis(benzoyl) tridecanedioic acid dihydrazide (NA)) as organic nucleating agent for poly(L-lactic acid) (PLLA) was evaluated by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and wide angle X-ray diffraction (WAXD). Compared to neat PLLA, NA could increase the overall crystallization rate of PLLA. Upon the addition of 0.8% NA, the crystallization peak temperature increased from 96.28 to 113.58 , and the crystallization enthalpy increased from 1.379 Jg-1 to 30.51 Jg-1. POM showed that the spherulite number of PLLA increased and the spherulite size significantly reduced in the presence of NA. The results of melting behavior at different conditions showed that the melting behavior of PLLA/NA samples was affected significantly by crystallization time, crystallization temperature and cooling rate. And there existed double-melting peaks resulting from melting-recrystallization at low crystallization temperature. (author)