用傅里叶变换红外光谱法研究聚对苯二甲酸乙二酯的结构

用傅里叶变换红外光谱法,将一系列不同温度下退火的PET光谱与熔融淬火的PET光谱进行数字吸光度相减,得到不同结晶状态的“反式构象光谱”。进一步将不同温度退火的“反式构象光谱”(240℃和120℃)彼此相减,可得到“纯晶区的光谱”和“非晶区的反式构象光谱”。通过差示光谱的比较,发现一些新的谱带和谱带的变化。可用PET 的晶区和非晶区中其分子链的内旋转构象的变化解释。

THE STUDY OF THE STRUCTURE OF POLYETHYLENE TEREPHTHALATE BY MEANS OF FOURIER TRANSFORM INFRARED SPECTROSCOPY

By means of FI-IR digital absorbancp subtraction technique the melt quenched PET spectrum was subtracted from those of the PET spectra annealed at different temperatures. By removal of the bands associated with gauche conformation, a series of "trans conformation spectra" corresponding to different crystalline states were obtained.After that, the two "trans conformation spectra" annealed at 240℃ and 120℃ respectively are subtracted each other. The "pure crystalline spectra" and "amorphous trans conformation spectra" are thus calculated. From these differenes spectra, some new bands and the changes of bands of the spectra are found. These results can be explained by the changes of chain rotational conformation associated respectively with crystalline and amorphous region in PET.