Abstract For grafted copolyimides with variable length and grafting density of polymethylmethacrylate side chains, the molecular masses were determined using three modes of SEC analysis, which differ in the detectors set. The results were compared with the values obtained (i) using 1H NMR spectra, (ii) those calculated by summing the molecular masses of homopolymer linear blocks that make up the copolymer, as well as (iii) with the absolute values of molecular masses determined by sedimentation-diffusion analysis. It is shown that for branched grafted copolyimides the use of only a refractometric detector or its combination with a viscometric detector in the SEC analysis did not allow for obtaining reliable molecular masses. On the contrary, the combination of refractometric and viscometric detectors with a light scattering detector provided for the determination of the molecular masses close to the respective absolute values. It is also shown that for linear block copolymers, unlike branched copolymers, the molecular masses close to the absolute values can be obtained using any of the three modes of SEC analysis. For the first time, a concept of the critical molecular mass of the side chains of grafted copolyimides is introduced as a quantitative criterion that takes into account the total length and also the density of grafting of the side chains.

中文翻译：

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以 PMMA 嵌段为模型系统的支链和线性共聚酰亚胺的不同拓扑结构共聚物的 SEC 分析

摘要 对于聚甲基丙烯酸甲酯侧链长度和接枝密度可变的接枝共聚酰亚胺，使用三种SEC分析模式测定分子量，这三种模式的检测器设置不同。将结果与 (i) 使用 1 H NMR 光谱获得的值，(ii) 通过将构成共聚物的均聚物线性嵌段的分子量相加计算得出的值，以及 (iii) 与确定的分子量绝对值进行比较通过沉降-扩散分析。结果表明，对于支化接枝共聚酰亚胺，在 SEC 分析中仅使用折光检测器或其与粘度检测器的组合无法获得可靠的分子量。相反，折光和粘度检测器与光散射检测器的组合，用于测定接近各自绝对值的分子质量。还表明，对于线性嵌段共聚物，与支化共聚物不同，使用三种 SEC 分析模式中的任何一种都可以获得接近绝对值的分子量。首次引入了接枝共聚酰亚胺侧链临界分子量的概念作为定量标准，该标准考虑了侧链的总长度和接枝密度。使用 SEC 分析的三种模式中的任何一种都可以获得接近绝对值的分子量。首次引入了接枝共聚酰亚胺侧链临界分子量的概念作为定量标准，该标准考虑了侧链的总长度和接枝密度。使用 SEC 分析的三种模式中的任何一种都可以获得接近绝对值的分子量。首次引入了接枝共聚酰亚胺侧链临界分子量的概念作为定量标准，该标准考虑了侧链的总长度和接枝密度。