A New Route of Manipulation of Poly(L-lactic acid) Crystallization by Self-Assembly of p-tert-Butylcalix[8]arene and Toluene

A novel nucleating agent (TBC8-t), self-assembled with p-tert-butylcalix[8]arene (TBC8) and toluene, was used to manipulate the crystallization behavior of poly(L-lactic acid) (PLLA). Toluene molecules were used to adjust the crystallization structure of TBC8. Differential scanning calorimetry results show that the crystallization peak temperature (T-c) and crystallization rate (Delta H-c/time) of PLLA nucleated with TBC8-t are 132.3 degrees C and 0.24 J/gs, respectively, which are much higher than that with conventional nucleating agent-talc (T-c = 119.3 degrees C, Delta H-c/time = 0.13 J/gs). The results of polarized optical microscopy demonstrate that TBC8-t could greatly enhance the crystallization rate of PLLA by increasing the nucleation rate rather than crystal growth rate. Along with an improvement of the crystallization rate, the crystalline morphology of PLLA is also affected by TBC8-t. The addition of TBC8-t transforms most of the original spherulite crystals into sheaf-like crystals. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1235-1243, 2010