二甲基硅油C-Si伸缩振动模式红外光谱研究

Infrared Spectroscopy Study of Silicone Oil C-Si Stretching Vibration

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(νCH_3)、CH_3变形振动模式(δCH_3)、CH_3摇摆振动模式(ρCH_3)、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 derivative 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 CH3 stretch vibration mode（vch3）,the CH3 bending vibration mode（δch3）,the CH3 swing vibration mode（ρch3）,the Si-O stretch vibration mode（vsi-o） and the Si-C stretch vibration mode（vsi-c） were found from 1800cm^（-1） to 600 cm^（-1）.The vsi-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 ATRFTIR in the analysis of thermal denaturation of the silicone oil.