凝胶渗透色谱法测定共聚酰胺热熔胶分子质量及其分布

摘要

The polymethyl methacrylate (PMMA) samples with the molecular weight of 7 500~122 500 were selected as the standard substance and dissolved in hexafluoroisopropanol (HFIP) to confect into the standard materials with mass fraction of 0.1%. The standard materials were analyzed by GPC with a refractive index detector, the silica gel column and HFIP as the mobile phase at flow ratio of 1.0 mL/min and 25℃, and the working curve of molecular weight vs elution volume (LogM~V) was obtained. The appropriate amount of co-polyamide hot-melt adhesive was weighed and dissolved in HFIP to prepare the solution with mass fraction of 0.1% , the molecular weight and its distribution of the co-polyamide hot-melt adhesive was determined according to above chromatographic conditions, and verified by light scattering method. The results showed that the GPC method can determine the molecular weight and its distribution of co-polyamide hot-melt adhesive in range of 10 000 and 100 000 with the average deviation of 1.61% .%以相对分子质量为7500～122500的聚甲基丙烯酸甲酯（PMMA）为标准物质，六氟异丙醇（HFIP）为溶剂，分别配制质量分数为0.1%的标准样品，采用凝胶渗透色谱仪，示差检测器，硅胶色谱柱，六氟异丙醇为流动相，流速1.0 mL/min，柱温25℃的色谱条件对上述标准样品进行逐一分析，获得分子质量-洗脱体积标准工作曲线（LogM-V）；称取适量的共聚酰胺热熔胶样品，用六氟异丙醇溶解至质量分数0.1%的溶液，根据上述色谱条件分析，测定共聚酰胺热熔胶分子质量及其分布，并用光散射法对所得结果进行验证，结果表明该方法可用来测定相对分子质量为10000100000的共聚酰胺热熔胶，所得重均分子质量Mw与光散射法测定值之间的平均误差为1.61%。