Crystallization kinetics of poly (butylene terephthalate) (non-talc-PBT) and its 0.1 wt % talc composites (talc-PBT) was determined for a wide range of cooling rates and isothermal temperatures. The critical cooling rate to suppress crystallization is 2000 K s 21 for non-talc-PBT and 7000 K s 21 for talc-PBT. The cooling rate dependence of the total enthalpy change and heating rate dependence of enthalpy of cold crystallization are quantitatively discussed on the basis of the Ozawa's method. For isothermal crystallization, the annealing-temperature (T iso ) dependence of crystallization half-time (t 1/2 ) shows a bimodal curve with two minima. Talc shortens the t 1/2 at T iso above 340 K and acts as a heterogeneous nucleation agent. Tammann's approach revealed that the t 1/2 is shortened by pre-nucleation for non-talc-PBT but not for talc-PBT.

No abstract

Fast scanning calorimetry (FSC) has been used to investigate the kinetics of nonisothermal crystallization, isothermal crystallization, and melting for semicrystalline polymers (ie, poly(butylene terephthalate, polyphenylene sulfide, and isotactic polypropylene). The scanning rate dependence of enthalpy of melt‐crystallization, cold‐crystallization, and recrystallization obtained from FSC are quantitatively explained on the basis of Ozawa's method. For isothermal kinetics, FSC allows to obtain the annealing‐temperature dependence of crystallization half‐time in a wide range of the supercooling without any unwanted nucleation or crystallization during cooling. The effect of additives for nonisothermal or isothermal crystallization was also considered in this article. In addition, hyphenated technique of FSC and polarized optical microscopy clearly shows the differences in crystallization kinetics and morphologies.

The lamellar thickness distribution (LTD) of not-reorganized linear polyethylene was calculated on the basis of the melting point distribution using fast scanning calorimetry (FSC) by applying the following precautions. First, by taking sufficiently small sample mass and thickness, the influence of thermal lag during fast-heating is thought to be negligible. Second, by fastheating, reorganization and cold crystallization are strongly hindered or even suppressed. Third, the influence of superheating has been accounted for and corrected by deconvolution of the FSC curve using the calculated melting kinetics of single-sized lamellae consisting of folded-chain crystal. Under such precautions, the resulting FSC heating curve reflects the melting point distribution of metastable-but-not-reorganized folded-chain crystals. Finally, the Gibbs−Thomson equation was applied to calculate the LTD from the melting point distribution. The average lamellar thickness calculated was in good agreement with that determined by small-angle X-ray scattering and lowfrequency Raman spectroscopy.