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本文叙述了聚丙烯腈中微量酸性基团的非水电位滴定法。本法以提纯过的碳酸乙烯酯—碳酸丙烯酯混合物作为溶剂,溶于这一溶剂中的四甲基氢氧化铵作为优良的滴定剂。使用铂电极,可允许在钠盐及钾盐存在的情况下测定聚合体中的酸性基因,从而防止了玻璃—甘汞电极的碱金属中毒。聚合体试样以适当的树脂进行离子交换处理后,即可滴定其中以盐形式存在的酸性基团。本法的灵敏度足以区别同一聚合体样品中强、弱程度不同的各酸性基因,并可获得典型的滴定曲线。
This article describes the non-aqueous potentiometric titration of trace amounts of acidic groups in polyacrylonitrile. This method uses purified ethylene carbonate - propylene carbonate mixture as a solvent, tetramethylammonium hydroxide dissolved in this solvent as an excellent titrant. The use of a platinum electrode allows the determination of acid genes in the polymer in the presence of sodium and potassium salts, thereby preventing alkali-metal poisoning of the glass-calomel electrode. After the polymer sample has been ion-exchanged with the appropriate resin, the acid groups in the salt form can be titrated. The sensitivity of this method is sufficient to distinguish between different acid genes of different intensities and weaknesses in the same polymer sample, and a typical titration curve can be obtained.