In the present study, a reliable and robust method was developed to quantify the molecular weight discrimination that can occur in grafting to reactions via indirect MALDI-TOF quantification of the molecular weights of grafted chains by comparing the characteristics of the polymeric material before the grafting reaction with those of the unreacted material recovered after grafting. Two polystyrene samples with different molecular weights and narrow molecular weight distributions were employed to prepare model blends that were grafted to silicon wafers and an analytical method was developed and validated to assess and quantify the modification of the molecular weight distribution that takes place during the grafting to process. Particular attention was paid to the standardization of the sample treatment and to find the best data collection and calibration methodologies in order to have statistically significant data even in the presence of a very scarce amount of the sample. Furthermore, to evaluate the accuracy of the analytical procedure, the lack of suitable standard and certified materials required a further experiment to be carried out by comparing the new optimized MALDI-TOF method and direct measurements using TGA-GC-MS on a model blend containing deuterated and hydrogenated polystyrene samples with appropriate molecular weights and distributions. The optimized method was applied on samples obtained by a thermally induced grafting to reaction from ultrathin polymer films and, for the first time, to our knowledge, an enrichment effect occurring in the ultrathin grafted layer obtained from a melt was evidenced.

中文翻译：

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通过基质辅助激光解吸/电离飞行时间质谱法量化超薄聚合物薄膜接枝反应中的分子量歧视

在本研究中，通过比较接枝反应前聚合物材料的特性，开发了一种可靠且稳健的方法，通过间接 MALDI-TOF 量化接枝链的分子量，量化接枝反应中可能发生的分子量歧视接枝后回收的未反应材料。使用具有不同分子量和窄分子量分布的两种聚苯乙烯样品来制备接枝到硅片的模型共混物，并开发并验证了一种分析方法，以评估和量化接枝过程中发生的分子量分布的改变。过程。特别注意样品处理的标准化并寻找最佳数据收集和校准方法，以便即使在样品数量非常稀少的情况下也能获得具有统计意义的数据。此外，为了评估分析程序的准确性，由于缺乏合适的标准和认证材料，需要通过比较新优化的 MALDI-TOF 方法和使用 TGA-GC-MS 对含有具有适当分子量和分布的氘代和氢化聚苯乙烯样品。将优化的方法应用于通过热诱导接枝获得的样品 超薄聚合物薄膜的反应，据我们所知，首次证明了从熔体获得的超薄接枝层中发生的富集效应。