采用变温傅里叶变换衰减全反射红外光谱技术(ATR-FTIR)结合二维相关红外光谱技术,分别研究了聚对苯二甲酸乙二醇酯(PET)的羰基红外伸缩振动模式(νC=O)。研究发现: 玻璃转化温度(Tg)以下时,PET 的 νC=O的红外吸收频率包括1700 cm-1、1709 cm-1 和 1718 cm-1,而随着测定温度的升高(313 ~343 K),其红外吸收强度变化快慢顺序为: 1709 cm-1> 1700 cm-1> 1718 cm-1; 而当在 Tg以上时,PET 的 νC=O的红外吸收频率包括1709 cm-1 和 1718 cm-1,而随着测定温度的升高(353~393 K),PET 的 νC=O红外吸收强度变化快慢顺序为: 1718 cm-1> 1709 cm-1。本项研究拓展了 ATR 二维相关红外光谱技术在 PET 高分子材料热变性研究的范围。

The C=O stretch vibration (νC=O) of the polyethylene terephthalate (PET) had been studied by fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) and ATR two-dimensional infrared spectroscopy.The νC=O occurred respectively near 1700 cm-1,1709 cm-1 and 1718 cm-1(below glass transition temperature),and the sequence of νC=O intensity changes was 1709 cm-1> 1700 cm-1> 1718 cm-1 with the increase of temperature (313-343 K).But the νC=Owere observed near 1709 cm-1 and 1718 cm-1(above glass transition temperature),and the sequence of νC=O intensity changes was 1718 cm-1>1709 cm-1 with the increase of temperature (353-393 K).The paper demonstrated the key roles of ATR two-dimensional infrared spectroscopy in the analysis of thermal denaturation of the PET.