Hiller Wolf, Pasch Harald, Macko Tibor, Hofmann Martin, Ganz Jürgen, Spraul Manfred, Braumann Ulrich, Streck Roman, Mason Jeff, Van Damme Freddy
German Institute for Polymers (DKI), Schlossgartenstr. 6, 64289 Darmstadt, Germany.
J Magn Reson. 2006 Dec;183(2):290-302. doi: 10.1016/j.jmr.2006.09.004. Epub 2006 Oct 11.
The on-line coupling of gel permeation chromatography (GPC) and 1H NMR operating at temperatures up to 130 degrees C is presented. A NMR flow probe with a cell volume of 120 microL and a stop-flow valve are developed for on-flow and stop-flow NMR measurements at high temperatures. To maintain high and constant temperatures through the whole probe, the flow probe contains two separate heating circuits. A modified stop-flow valve is developed as a control device for enabling on-flow and stop-flow experiments at high temperature conditions. Heated transfer lines connect the flow probe with the high temperature GPC system. Due to their semicrystalline nature, polyolefins can be studied by liquid chromatography only at temperatures above 100 degrees C. The novel high temperature GPC-NMR system is used for the separation of complex polyolefins regarding their molar mass and for the analysis of different chemical structures. Blends of polyethylene, poly(methyl methacrylate), and ethylene-methyl methacrylate copolymers are separated according to the molar masses of the components. The compositions of the components are directly studied by on-line NMR. Moreover, the chemical composition distribution of an ethylene-methyl methacrylate copolymer sample is analysed. Differences between results of on-flow and stop-flow measurements are discussed.
本文介绍了凝胶渗透色谱（GPC）与¹H NMR在高达130℃温度下的在线联用。开发了一种样品池体积为120微升的NMR流动探头和一个停流阀，用于高温下的流动和停流NMR测量。为了使整个探头保持高温且温度恒定，该流动探头包含两个独立的加热回路。开发了一种改进的停流阀作为控制装置，以便在高温条件下进行流动和停流实验。加热传输线将流动探头与高温GPC系统相连。由于聚烯烃的半结晶性质，只能在高于100℃的温度下通过液相色谱对其进行研究。新型高温GPC-NMR系统用于按摩尔质量分离复杂聚烯烃，并分析不同的化学结构。聚乙烯、聚甲基丙烯酸甲酯和乙烯-甲基丙烯酸甲酯共聚物的共混物按组分的摩尔质量进行分离。通过在线NMR直接研究各组分的组成。此外，还分析了乙烯-甲基丙烯酸甲酯共聚物样品的化学组成分布。讨论了流动和停流测量结果之间的差异。
