乳胶C-H面外摇摆振动模式ATR二维红外光谱研究

ATR Two-Dimensional Infrared Spectroscopy Study of Latex the C-H Wagging Vibration

在303~393K温度范围内,采用变温傅里叶变换衰减全反射红外光谱(ATR-FTIR)技术,研究了乳胶的分子结构。实验发现:在3500~600cm^(-1)的频率范围内,乳胶主要存在着C-H伸缩振动模式(ν_(C-H))、C=C双键伸缩振动模式(ν_(C=C))、CH_2弯曲振动模式(δ_(CH2))、CH_3弯曲振动模式(δ_(CH3_)和双键上C-H面外摇摆振动模式(ω_(C-H))等五种。本文主要以乳胶ω_(C-H)为研究对象,进一步开展相关二维红外光谱的研究,考查温度对于乳胶分子结构的影响。研究发现:乳胶ω_(C-H)在837cm^(-1)和841cm^(-1)频率处有红外吸收峰,而随着测定温度的升高,乳胶ωC-H红外吸收强度的变化快慢顺序为:837cm^(-1)>841cm^(-1)。此项研究拓展了ATR-FTIR技术在乳胶热变性方面的研究范围。

The latex organic molecular were characterized by Fourier transform attenuated total reflection infrared spectroscopy(ATR-FTIR)in the temperature range 303~393K.The C-H stretch vibration(ν_(C-H)),C=C stretch vibration(ν_(C=C)),CH_2 bending vibration(δ_(CH2)),CH_3 bending vibration mode(δ_(CH3))and C-H wagging vibration(ω_(C-H)) were found in the region between 3500~600cm^(-1).Two-dimensional infrared spectra of latex(ω_(C-H)) were studied to determine the sequence of intensity changes.Actually two bands were observed:one at 837cm^(-1) and one at 841cm^(-1).It had been found that the sequence of intensity changes was 837cm^(-1)> 841cm^(-1) when the temperature increased.The study demonstrated the key roles of ATR-FTIR in the analysis of thermal denaturation of the latex.