乙纶分子结构及热变性三级长波近红外-中红外光谱研究

Study on the Molecular Structure and Thermal Denaturation of Polyethylene Fibers by Three-stage Long Wave Near Infrared-Mid infrared Spectroscopy

长波近红外-中红外(LW-NIR-MIR)光谱开展乙纶分子结构研究。红外模式主要包括:2ν_(asCH3-去卷积-乙纶)、2ν_(asCH2-去卷积-乙纶)、2ν_(sCH3-去卷积-乙纶)、2ν_(sCH2-去卷积-乙纶)、(ν_(asCH2-去卷积-乙纶)+ν_(CH-去卷积-乙纶))、(ν_(asCH2-去卷积-乙纶)+ν_(sCH2-去卷积-乙纶))、ν_(asCH3-去卷积-乙纶)、ν_(sCH3-去卷积-乙纶)、ν_(asCH2-去卷积-乙纶)、ν_(sCH2-去卷积-乙纶)、δ_(CH2-去卷积-乙纶)和ρ_(CH2-去卷积-乙纶)。进一步开展了变温LW-NIR-MIR光谱研究。在303 K~393 K的温度范围内,结构官能团(2ν_(sCH2-去卷积-乙纶),ν_(asCH2-去卷积-乙纶)和ρ_(CH2-去卷积-乙纶))对应频率及强度都有明显改变。最后开展二维LW-NIR-MIR光谱研究。LW-NIR区间,5835 cm^(-1)(2ν_(asCH2-2-二维-乙纶))>5700 cm^(-1)(2ν_(sCH2-二维-乙纶))>5867 cm^(-1)(2ν_(asCH2-1-二维-乙纶))>5800 cm^(-1)(ν_(asCH2-二维-乙纶)+ν_(CH-二维-乙纶))>5762 cm^(-1)(ν_(asCH2-二维-乙纶)+ν_(sCH2-二维-乙纶))>5894 cm^(-1)(2ν_(asCH3-二维-乙纶))。MIR区间,2915 cm^(-1)(ν_(asCH2-二维))>2845 cm^(-1)(ν_(sCH2-二维-乙纶))>2945 cm^(-1)(ν_(asCH3-二维-乙纶))>2885 cm^(-1)(ν_(sCH3-二维-乙纶))。1452 cm^(-1)(δ_(CH2-2-二维-乙纶))>1475 cm^(-1)(δ_(CH2-1-二维-乙纶))。LW-NIR-MIR区间,5835 cm^(-1)(2ν_(asCH2-2-二维-乙纶))>2915 cm^(-1)(ν_(asCH2-二维-乙纶))>2845 cm^(-1)(ν_(sCH2-二维-乙纶))>5894 cm^(-1)(2ν_(asCH3-二维-乙纶))。乙纶分子结构主要官能团对热的敏感程度及变化快慢顺序都存在着较大的差异性。研究拓展了三级LW-NIR-MIR谱在乙纶分子结构及热变性的研究范围。

Long wave-near infrared-mid infrared(LW-NIR-MIR)spectroscopy was used to study the molecular structure of polyethylene fibers.It is found that the infrared absorption modes mainly include:2ν_(asCH3-deconvolution-polyethylene fibers),2ν_(asCH2-deconvolution-polyethylene fibers),2ν_(sCH3-deconvolution-polyethylene fibers),2ν_(sCH2-deconvolution-polyethylene fibers),(ν_(asCH2-deconvolution-polyethylene fibers)+νCH-deconvolution-polyethylene fibers),(ν_(asCH2-deconvolution-polyethylene fibers)+ν_(sCH2-deconvolution-polyethylene fibers)),ν_(asCH3-deconvolution-polyethylene fibers),ν_(sCH3-deconvolution-polyethylene fibers),ν_(asCH2-deconvolution-polyethylene fibers),ν_(sCH2-deconvolution-polyethylene fibers),δ_(CH2-deconvolution-polyethylene fibers) andρ_(CH2-deconvolution-polyethylene fibers).Further research was conducted on the LW-NIR-MIR spectroscopy at variable temperatures.In the temperature range of 303~393 K,the main functional groups(2ν_(sCH2-deconvolution-polyethylene fibers),ν_(asCH2-deconvolution-polyethylene fibers) andρ_(CH2-deconvolution-polyethylene fibers))frequency and intensity had significant changed.Finally,two-dimensional LW-NIR-MIR spectroscopy study was carried out.In the NIR-MIR range,5835 cm^(-1)(2νasCH2-2-two-dimensional-polyethylene fibers)>5700 cm^(-1)(2νsCH2-two-dimensional-polyethylene fibers)>5867 cm^(-1)(2νasCH2-1-two-dimensional-polyethylene fibers)>5800 cm^(-1)(ν_(asCH2-two-dimensional-polyethylene fibers)+νCH-two-dimensional-polyethylene fibers)>5762 cm^(-1)(ν_(asCH2-two-dimensional-polyethylene fibers)+νsCH2-two-dimensional-polyethylene fibers)>5894 cm^(-1)(2ν_(asCH3-two-dimensional-polyethylene fibers)).In the MIR range,2915 cm^(-1)(νasCH2two-dimensional-polyethylene fibers)>2845 cm^(-1)(νsCH2-two-dimensional-polyethylene fibers)>2945 cm^(-1)(νasCH3-two-dimensional-polyethylene fibers)>2885 cm^(-1)(νsCH3-two-dimensional-polyethylene fibers).1452 cm^(-1)(δCH2-2-two-dimensional-polyethylene fibers)>1475 cm^(-1)(δCH2-1-two-dimensional-polyethylene fibers).In the range of LW-NIR-MIR range,5835 cm^(-1)(2νasCH2-2-two-dimensional-polyethylene fibers)>2915 cm^(-1)(ν_(asCH2-two-dimensional-polyethylene fibers))>2845 cm^(-1)(νsCH2-two-dimensional-polyethylene fibers)>5894 cm^(-1)(2ν_(asCH3-two-dimensional-polyethylene fibers)).The main functional groups of polyethylene fibers molecular structure have great differences in the sensitivity to heat and the order of change.This research expanded the research scope of three-stage LW-NIR-MIR spectroscopy in the molecular structure and thermal denaturation of polyethylene fibers molecules.