二甲基硅油 C-Si 伸缩振动模式红外光谱研究∗

摘要

在303~393 K 温度范围内，采用变温傅里叶变换衰减全反射红外光谱技术(ATR-FTIR)研究了二甲基硅油的一维红外光谱、二阶导数红外光谱、四阶导数红外光谱和去卷积红外光谱。实验发现，在1800~600 cm-1范围内，二甲基硅油主要存在 CH 3伸缩振动模式(νCH3)、CH 3变形振动模式(δCH3)、CH 3摇摆振动模式(ρCH3)、Si-O伸缩振动模式(νSi-O )和 Si-C 伸缩振动式(νSi-C )等5种红外吸收模式，其中782 cm-1和789 cm-1处的红外吸收峰归属于二甲基硅油νSi-C 。以二甲基硅油νSi-C 为研究对象，进一步开展相关二维红外光谱的研究。结果发现，随着测定温度的升高，二甲基硅油νSi-C 红外吸收强度的变化快慢顺序为：789 cm-1>782 cm-1。本项研究拓展了 ATR-FTIR 技术在二甲基硅油热变性方面的研究范围。%The silicone oil molecular structure was studied by one-dimensional infrared spectroscopy,second de-rivative infrared spectroscopy,fourth derivative infrared spectroscopy and deconvolution infrared spectroscopy with fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR)in the temperature range from 303 K to 393 K.The CH 3 stretch vibration mode (νCH3 ),the CH 3 bending vibration mode (δCH3 ),the CH 3 swing vibration mode (ρCH3 ),the Si-O stretch vibration mode (νSi-O )and the Si-C stretch vibration mode (νSi-C )were found from 1800 cm-1 to 600 cm-1 .TheνSi-C occurred respectively near 782 cm-1 and 789 cm-1 .Two-dimensional infrared spectra of silicone oil was studied to determine the sequence of intensity changes.It had been found that the sequence of intensity changes was 789 cm-1 >782 cm-1 with the increase of temperature.The study demonstrated the key roles of ATR-FTIR in the analysis of thermal denaturation of the silicone oil.