A dynamical study of the melting behavior of polypivalolactone single crystals by the X‐ray diffraction method

Abstract

AbstractWide‐angle and small‐angle X‐ray diffraction patterns of polypivalolactone single crystals were recorded as a function of temperature while heating at a constant rate. Long periods were found to increase abruptly at a certain temperature, while the degree of crystallinity decreased up to that temperature and then recovered on further heating, to an extent depending on the rate of heating. Multiple endotherms were observed in DSC measurements. The temperature at which the first endotherm peak was observed corresponded exactly to the temperature of the long period jump mentioned above. From these data, it is concluded that the original lamellar crystals melt at each peak temperature in the DSC thermogram and new lamellae are produced by subsequent crystallization. Multiple endotherms in the DSC thermogram are thus considered to represent repeated melt‐recrystallization processes.