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聚已内醯胺的端基滴定测定分子量,可以用同一溶剂[苯甲醇,甲醇-水(2:1)混合溶剂],在同一温度(室温)时用電導、電位或指示剂法分别先後进行氨基和羧基的滴定。滴定剂用标准盐酸和氢氧化鉀的甲醇-水溶液(约0.03N),電導法及電位法滴定羧基時另加甲醛抑制氨基,所得滴定曲线良好。指示剂法的终點均清晰。三法分别自氨基或羧基测得的聚合物数均分子量相互一致。确立了用这三种方法进行端基滴定的可靠性。但是同一试样自氨基测得的分子量,一般均高於自羧基测得的分子量。
The end group titration of polycaprolactam molecular weight determination, you can use the same solvent [benzyl alcohol, methanol - water (2: 1 mixed solvent]) at the same temperature (room temperature) with conductance, potential or indicator were followed Amino and carboxyl titration. Titration with standard hydrochloric acid and potassium hydroxide in methanol - aqueous solution (about 0.03N), the conductivity method and the potential method titration of carboxyl plus formaldehyde to inhibit the amino group, the resulting titration curve is good. End point indicator method are clear. Three methods were measured from the amino or carboxyl polymer number average molecular weight consistent with each other. The reliability of end-group titration with these three methods has been established. However, the molecular weight of the same sample measured from the amino group is generally higher than the molecular weight measured from the carboxyl group.