四氧化钌对聚乙二醇的染色行为

Staining of polyethylene glycol (PEG) by RuO_4

在用透射电镜(TEM)研究聚合物的领域,四氧化钌(RuO4)是常用的染色剂。RuO4可对聚乙二醇(PEG)染色,从而提高与其他聚合物的共混物在TEM观察中图像的衬度。为探索RuO4对PEG的染色行为,本文采用傅里叶红外光谱法(FTIR)研究了RuO4染PEG的化学反应机理,发现RuO4将PEG氧化成酯、羧酸及羧酸盐。并用凝胶色谱法(GPC)对比染色前后PEG分子量的变化,发现染色后PEG除了被氧化成酯、羧酸及羧酸盐外,还有部分发生交联。采用微商热重法(DTG)研究染色前后化合物的热稳定性,发现染色后聚合物热稳定性增强。

The staining of PEG by RuO4 has been studied in detail and shown to result in a good contrast in TEM images of blends of PEG with polymethyl methacrylate(PMMA).IR spectroscopy suggests that CH2 groups in the polymer chain are oxidized to carboxylic ester,carboxylic acid or carboxylate groups in the staining process,whilst RuO4 is reduced to RuO2.GPC analysis shows that the molecular weight of the PEG increases after staining,which suggests that cross-linking occurs when PEG is stained by RuO4.DTG analysis indicates that the stained PEG is more thermally stable than unstained PEG.