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将原位全反射傅立叶红外光谱(in situATR-FTIR)技术应用于研究稀土催化丁二烯配位聚合反应过程,探讨了采集FTIR谱图的背景、用于定量计算的特征峰的选择与确定、单体浓度和所确定的特征峰强度的关系及丁二烯溶液聚合反应动力学.在聚合过程中不同时间取样得到聚合物样品,采用GPC、FTIR、POM和DSC分别对这些样品进行分子量及其分布、微观结构及其含量、玻璃化温度及结晶特性的分析与表征.结果表明,选用溶剂正己烷为背景,采集的FTIR谱图(600~1800 cm-1)中仅出现丁二烯的3个特征峰1592、1010和904 cm-1,且基线更为平滑,计算误差小.在丁二烯浓度为0.46~3.88 mol.L-1的范围内,丁二烯的这3个特征峰的强度均与丁二烯浓度成正比,其中904 cm-1处的特征峰强,可选作定量计算的特征峰.聚合反应速率对单体浓度呈现一级动力学关系,表观增长活化能为56.5 kJ.moL-1.聚丁二烯产物的分子量随单体转化率呈线性增加,其GPC谱图表明所得聚合物的分子量呈单峰分布,分布指数(Mw/Mn)在2.5左右.聚丁二烯产物中顺-1,4结构含量大于98%,其玻璃化转变温度约为-109℃,可产生较明显的结晶现象.
The in situ ATTR-FTIR technique was applied to the study of rare earth catalyzed coordination polymerization of butadiene. The background of the FTIR spectra acquisition, the selection and determination of characteristic peaks for quantitative calculation, Monomer concentration and the relationship between the intensity of the characteristic peak and butadiene solution polymerization kinetics.Polymer samples were obtained at different times during the polymerization process.The molecular weights of these samples were determined by GPC, FTIR, POM and DSC Distribution, microstructure and its content, glass transition temperature and crystallization characteristics were studied.The results showed that only 3 of butadiene was found in the FTIR spectra (600 ~ 1800 cm-1) The characteristic peaks are 1592, 1010 and 904 cm-1, and the baseline is smoother and the calculation error is small.With the concentration of butadiene at 0.46 ~ 3.88 mol.L-1, the three characteristic peaks of butadiene The intensity is proportional to the concentration of butadiene, and the characteristic peak at 904 cm-1 is the characteristic peak for quantitative calculation. The polymerization rate shows a first-order kinetic relationship with monomer concentration and the apparent activation energy 56.5 kJ.moL-1. Score of polybutadiene product The molecular weight of the polybutadiene product increases linearly with the conversion of the monomer, and the GPC chromatogram shows that the molecular weight of the obtained polymer has a single peak distribution with a distribution index (Mw / Mn) of about 2.5. More than 98%, the glass transition temperature of about -109 ℃, can produce more obvious crystallization phenomenon.