聚偏二氟乙烯δ_(CH2)三级中红外光谱研究

Three-level MIR Spectroscopy of Polyvinylidene Difluoride(δ_(CH2))

采用中红外(MIR)光谱开展聚偏二氟乙烯的分子结构研究.实验发现:聚偏二氟乙烯分子红外吸收模式主要包括:ν_(asCH2)、ν_(sCH2)、δ_(CH2)、ν_(asCF2)和ν_(sCF2).进一步开展了聚偏二氟乙烯分子变温中红外(TD-MIR)光谱研究.实验发现:随着测定温度的升高,聚偏二氟乙烯分子δ_(CH2)对应的红外吸收频率及强度均有明显的改变.采用二维中红外(2D-MIR)光谱,进一步开展了聚偏二氟乙烯热老化性研究.相变前,聚偏二氟乙烯分子δ_(CH2)-二维-相变前对应的吸收频率包括:1430 cm^(-1)(δ_(CH2)-二维-1-晶体-相变前)、1420 cm^(-1)(δ_(CH2)-二维-2-相变前)、1406 cm^(-1)(δ_(CH2)-二维-3-晶体-相变前)和1380 cm^(-1)(δ_(CH2)-二维-4-相变前).热扰动下,聚偏二氟乙烯分子δ_(CH2)-二维-相变前吸收峰变化快慢信息为:1430 cm^(-1)(δ_(CH2)-二维-1-晶体-相变前)>1420 cm^(-1)(δ_(CH2)-二维-2-相变前)>1380 cm^(-1)(δ_(CH2)-二维-4-相变前)>1406 cm^(-1)(δ_(CH2)-二维-3-晶体-相变前).相变过程中,聚偏二氟乙烯分子δ_(CH2)-二维-相变过程中对应的吸收频率包括:1432 cm^(-1)(δ_(CH2)-二维-1-晶体-相变过程中)、1420 cm^(-1)(δ_(CH2)-二维-2-相变过程中)、1407 cm^(-1)(δ_(CH2)-二维-3-晶体-相变过程中)、1400 cm^(-1)(δ_(CH2)-二维-4-相变过程中)和1382 cm^(-1)(δ_(CH2)-二维-5-相变过程中).热扰动下,聚偏二氟乙烯分子δ_(CH2)-二维-相变过程中吸收峰变化快慢信息为:1400 cm^(-1)(δ_(CH2)-二维-4-相变过程中)>1382 cm^(-1)(δ_(CH2)-二维-5-相变过程中)>1407 cm^(-1)(δ_(CH2)-二维-3-晶体-相变过程中)>1432 cm^(-1)(δ_(CH2)-二维-1-晶体-相变过程中)>1420 cm^(-1)(δ_(CH2)-二维-2-相变过程中).相变后,聚偏二氟乙烯分子δ_(CH2)-二维-相变后对应的吸收频率包括:1432 cm^(-1)(δ_(CH2)-二维-1-晶体-相变后)、1420 cm^(-1)(δ_(CH2)-二维-2-相变后)、1406 cm^(-1)(δ_(CH2)-二维-3-晶体-相变后)和1380 cm^(-1)(δ_(CH2)-二维-4-相变后).热扰动下,聚偏二氟乙烯分子δ_(CH2)-二维-相变后吸收峰变化快慢信息为:1380 cm^(-1)(δ_(CH2)-二维-4-相变后)>1432 cm^(-1)(δ_(CH2)-二维-1-晶体-相变后)>1420 cm^(-1)(δ_(CH2)-二维-2-相变后)>1406 cm^(-1)(δ_(CH2)-二维-3-晶体-相变后).实验发现:聚偏二氟乙烯的红外吸收峰(δ_(CH2))对热敏感程度及变化顺序都存在着较大的差异性.拓展了三级MIR光谱在重要的纺织材料(聚偏二氟乙烯)结构及热老化性的研究范围.

The molecular structure of polyvinylidene difluoride(PVDF)was studied by infrared(MIR)spectroscopy.The experiment discovered that the infrared absorption modes of PVDF included νa_(sCH2),ν_(sCH2),δ_(CH2),νa_(sCF2) andν_(sCF2).And the temperature-dependent infrared(TD-MIR)spectroscopy of PVDF were studied also.With the increase of the temperature,the corresponding infrared absorption frequency and intensity of PVDF(δ_(CH2))changed obviously.The thermal aging properties of PVDF were considered by two dimensional infrared(2D-MIR)spectroscopy.Before phase transition,the corresponding absorption frequency of PVDF(δ_(CH2)-2D-before phase transition)included 1430cm^(-1)(δ_(CH2)-2D-1-crystal-before phase transition),1420cm^(-1)(δ_(CH2)-2D-2-before phase transition),1406 cm^(-1)(δ_(CH2)-2D-3-crystal-before phase transition)and 1380cm^(-1)(δ_(CH2)-2D-4-before phase transition).Under thermal disturbance,the sequence of infrared absorption peak change of PVDF(δ_(CH2)-2D-before phase transition)were 1430cm^(-1)(δ_(CH2)-2D-1-crystal-before phase transition)>1420cm^(-1)(δ_(CH2)-2D-2-before phase transition)>1380cm^(-1)(δ_(CH2)-2D-4-before phase transition)>1406 cm^(-1)(δ_(CH2)-2D-3-crystal-before phase transition).During phase transition,the corresponding infrared absorption frequency of PVDF(δ_(CH2)-2D-during phase transition)included 1432 cm^(-1)(δ_(CH2)-2D-1-crystal-during phase transition),1420 cm^(-1)(δ_(CH2)-2D-2-during phase transition),1407 cm^(-1)(δ_(CH2)-2D-3-crystal-during phase transition),1400 cm^(-1)(δ_(CH2)-2D-4-during phase transition)and 1382 cm^(-1)(δ_(CH2)-2D-5-during phase transition).Under thermal disturbance,the sequence of infrared absorption peak change of PVDF(δ_(CH2)-2D-during phase transition)were 1400 cm^(-1)(δ_(CH2)-2D-4-during phase transition)>1382 cm^(-1)(δ_(CH2)-2D-5-during phase transition)>1407 cm^(-1)(δ_(CH2)-2D-3-crystal-during phase transition)>1432 cm^(-1)(δ_(CH2)-2D-1-crystal-during phase transition)>1420 cm^(-1)(δ_(CH2)-2D-2-during phase transition).After phase transition,the corresponding infrared absorption frequency of PVDF(δ_(CH2)-2D-after phase transition)included 1432 cm^(-1)(δ_(CH2)-2D-1-crystal-after phase transition),1420 cm^(-1)(δ_(CH2)-2D-2-after phase transition),1406 cm^(-1)(δ_(CH2)-2D-3-crystal-after phase transition),1380 cm^(-1)(δ_(CH2)-2D-4-after phase transition).Under thermal disturbance,the se￣quence of infrared absorption peak change of PVDF(δ_(CH2)-2D-after phase transition)were1380 cm^(-1)(δ_(CH2)-2D-4-after phase transition)>1432 cm^(-1)(δ_(CH2)-2D-1-crystal-after phase transition)>1420 cm^(-1)(δ_(CH2)-2D-2-after phase transition)>1406 cm^(-1)(δ_(CH2)-2D-3-crystal-after phase transition).The experiments discovered that the infrared absorption peak of PVDF(δ_(CH2))showed great difference to heat sensitivity and change sequence.The study expanded the research scope of threelevel MIR spectroscopy in the analysis of structure and thermal aging properties of important textile materials(PVDF).