AbstractThe 13C NMR spectra of atactic copolymers of methyl methacrylate (MMA) and benzyl methacrylate (BnMA) show complicated resonance patterns due to variations in their configurational sequences and monomer sequences in the macromolecular chains. Principal component analysis (PCA) was found to be useful for extracting information regarding the chemical composition and monomer sequence from the complicated resonances of the copolymers. To assess the feasibility for monomer sequence analysis, a PCA approach was applied to the spectra of MMA-BnMA copolymers prepared by partial modification of atactic poly(benzyl methacrylate) through catalytic hydrogenolysis, acidic debenzylation, saponification, and transesterification and by two-step esterification of atactic poly(methacrylic acid) (PMAa). The analysis clearly showed the formation of highly blocky copolymers via hydrogenolysis, as well as the formation of copolymers with a somewhat alternating tendency via acidic debenzylation, saponification, and transesterification in the late processes of the reactions. The copolymers formed in early processes of these reactions were essentially random sequences. The analysis also revealed that the copolymer prepared through partial methylation of PMAa with diazomethane was a random copolymer, while the copolymer prepared through partial benzylation of PMAa with benzyl bromide was a blocky copolymer.MMA-BnMA copolymers with various monomer sequences (blocky, random, alternating tendency) were prepared by partial modifications of atactic poly(BnMA) or by direct copolymerization of MMA and BnMA. 13C NMR spectra of the copolymers were subjected to principal component analysis, one of the standard procedures of multivariate analysis. The analysis showed clearly the formation of highly blocky copolymers by hydrogenolysis as well as the formation of copolymers with somewhat alternating tendency by the acidic debenzylation, saponification, and transesterification at late processes of the reactions.

中文翻译：

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13C NMR 光谱的多变量分析以提取由各种聚合物反应制备的聚（甲基丙烯酸甲酯-共-甲基丙烯酸苄酯）中的单体序列信息

摘要 甲基丙烯酸甲酯 (MMA) 和甲基丙烯酸苄酯 (BnMA) 的无规立构共聚物的 13C NMR 光谱显示出复杂的共振模式，这是由于它们的构型序列和大分子链中单体序列的变化。发现主成分分析 (PCA) 可用于从共聚物的复杂共振中提取有关化学组成和单体序列的信息。为了评估单体序列分析的可行性，将 PCA 方法应用于通过催化氢解、酸性脱苄、皂化和酯交换以及两步酯化对无规立构聚（甲基丙烯酸苄酯）进行部分改性制备的 MMA-BnMA 共聚物的光谱无规立构聚（甲基丙烯酸）（PMAa）。分析清楚地表明通过氢解形成高度嵌段的共聚物，以及在反应的后期过程中通过酸性脱苄、皂化和酯交换形成具有某种交替趋势的共聚物。在这些反应的早期过程中形成的共聚物基本上是随机序列。分析还表明，PMAa 与重氮甲烷部分甲基化制备的共聚物为无规共聚物，而 PMAa 与溴化苄部分苄化制备的共聚物为嵌段共聚物。MMA-BnMA 共聚物具有多种单体序列（嵌段、无规、交替趋势）通过无规聚（BnMA）的部分改性或通过MMA和BnMA的直接共聚制备。对共聚物的 13C NMR 谱进行主成分分析，这是多变量分析的标准程序之一。分析清楚地表明通过氢解形成高度嵌段的共聚物，以及在反应后期通过酸性脱苄、皂化和酯交换形成具有某种交替趋势的共聚物。