凝胶渗透色谱用聚丙烯酸标样的制备

Preparation of Standard Polyacrylic Acid Samples for Gel Permeation Chromatography

以二氧六环为良溶剂,石油醚为沉淀剂,通过等温沉淀分级,制得8种不同分子量的聚丙烯酸标样。采用渐近校正法测定了它们的峰值分子量和分子量分布,建立了GPC校正曲线,并将其用于聚丙烯酸试样的测定。结果表明,由渐进校正法测得的粘均分子量与粘度法测得的分子量之间的平均相对误差为7%,由渐进校正法测得的数均分子量与端基滴定法测得分子量之间的平均相对误差为9%。将上述标样用于实际聚丙烯酸试样的测定,测得试样的粘均分子量与粘度法测定结果之间平均相对误差小于10%,优于以聚乙二醇为标样测定的平均相对误差(30%左右)。本标样可用于具有与聚丙烯酸相似结构的阴离子聚电解质分子量分布的测定。

Eight standard polyacrylic acid（PAA） samples with different molecular mass were obtained via an isothermal precipitation grading method by using dioxane as solvent and petroleum ether as precipitator.Their peak molecular mass and molecular mass distributions were determined from an asymptotic calibration method.The results showed that the average relative errors for Mη are about 7% and 9% compared with those obtained using viscometry end-group titration,respectively.When these standard samples were used for determining the molecular mass as well as their distributions for actual PAA samples,the average relative error is less than 10%,which is superior to that using polyethylene glycol（PEG） as standard samples（about 30%）.The PAA standard samples in gel permeation chromatography（GPC） might be extended to other anionic polyelectrolytes with similar structure for the same purpose.