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测定了聚 (N 异丙基丙烯酰胺 ) (PNIPAAM)的溶液高分辨定量1 3CNMR谱 ,使用γ gauche效应和Gaussian98从头计算GIAO CHF两种方法分别计算了各立构序列的化学位移 .结果表明在计算结果与实验数据之间的符合程度方面 ,从头计算方法明显优于γ gauche效应方法 .利用从头计算的结果对谱图作了相应归属 ,并分析了PNIPAAM的立构规整度 .结果表明PNIPAAM链的增长服从Bernoulli过程 ,立构序列满足无规分布 .这说明量化计算和NMR相结合是研究高分子高级链结构的有效方法 .
The chemical shifts of each stereostructure were calculated by high resolution quantitative 1 3 C NMR spectroscopy of the poly (N-isopropylacrylamide) (PNIPAAM) solution and the γ gauche effect and the Gaussian98 ab initio calculation of the GIAO CHF results, respectively The ab initio method is obviously superior to the γ gauche effect method in terms of the degree of correspondence between the calculated and experimental data. The spectra were attributed to ab initio calculations and the tacticity of PNIPAAM was analyzed. The results showed that PNIPAAM chain The growth follows the Bernoulli process, and the stereosequence satisfies the random distribution, which shows that the combination of quantitative calculation and NMR is an effective way to study the high-molecular chain structure.