Crystallization studies of poly(trimethylene terephthalate) using thermal analysis and far-infrared spectroscopy

摘要

Crystallization of poly(trimethylene terephthalate) (PTT) by annealing was examined using density measurement, differential scanning calorimetry, and far-infrared spectroscopy (FIR). Crystallinity, measured by density, increased slowly up to the T-a of 185 degrees C and increases rapidly once Ta exceeds 185 degrees C. It was found that thermally induced crystallization is mainly temperature-dependent above T-a = 185 degrees C and temperature and time-dependent below T-a = 60 degrees C. Two melting transitions, T-m(1) and T-m(2) were observed for those samples annealed above 120 degrees C. No significant change in T-m(1) was observed as a function of T. while V. showed strong dependency on Ta. Digital subtraction of the amorphous contribution from the semicrystalline FIR spectra provided characteristic spectra of amorphous and crystalline PTT. The bands at 373, 282, and 92 cm(-1) were assigned to the crystalline phase, while the bands at 525, 406, and 351 cm(-1) were attributed to the amorphous phase. It was shown that FIR spectroscopy can be used as a means to estimate the degree of crystallinity of PTT. The band ratio of 373 and 501 cm-1 was plotted against crystallinity measured by density and reasonably good correlation was obtained. (c) 2007 Wiley Periodicals, Inc.