塑料.用尺寸排阻色谱法测定聚合物的平均分子量和分子量分布.第5部分:光散射法

[中文适用范围]： 该文件规定了使用SEC-LS（即尺寸排阻色谱法与光散射检测相结合）测定聚合物的平均分子量和分子量分布的一般方法。 平均分子量和分子量分布由随洗脱时间连续测定的分子量数据和重量浓度计算。 通过将光散射检测器与浓度敏感检测器相结合来绝对确定每个洗脱时间的分子量。 因此，SEC-LS 被归类为绝对方法。 该方法适用于线性均聚物和非线性均聚物，例如支链、星形、梳状、立体规则和立体不规则聚合物。 它还可以应用于分子组成不能变化的多相共聚物。 然而，SEC-LS 不适用于分子组成可能变化的嵌段、接枝或多相共聚物。 该方法适用于单体分子量至 3000000 范围内的样品，但不适用于含有 > 30% 分子量 < 1000 的组分的样品。 [外文原描述]： This document specifies a general method for determining the average molecular weight and the molecular weight distribution of polymers using SEC-LS, i.e. size-exclusion chromatography coupled with light-scattering detection. The average molecular weight and the molecular weight distribution are calculated from molecular weight data and weight concentrations determined continuously with elution time. The molecular weight at each elution time is determined absolutely by combining a light-scattering detector with a concentration-sensitive detector. Therefore, SEC-LS is classified as an absolute method. This method is applicable to linear homopolymers and to nonlinear homopolymers such as branched, star-shaped, comb-like, stereo-regular and stereo-irregular polymers. It can also be applied to heterophasic copolymers whose molecular composition cannot vary. However, SEC-LS is not applicable to block, graft or heterophasic copolymers whose molecular composition can vary. And the methods are applicable to molecular weights ranging from that of the monomer to 3 000 000, but are not intended for samples that contain > 30 % of components having a molecular weight < 1 000.