Non-isothermal crystallization behavior of poly(ethylene terephthate)

Non-isothermal crystallization behavior of poly(ethylene terephthalate) was studied by means of infrared spectroscopy, differential-scanning calorimetry, X-ray diffraction and density method. The PET began to crystallize as the temperature higher than 110 degrees C. There isn't obvious change in the crystallinity from 160 to 230 degrees C. But the crystallinity of PET continually increases during the later cooling process. The crystallinity of slowly cooled sample from 230 degrees C is much higher than that of rapidly quenched sample. These results provide strong evidence for chain folding existing before crystallization.