具有分子取向的拉伸高聚物(PET)中^(13)C—NMR化学位移值的估算

PREDICTION OF ^(13)C-NMR CHEMICAL SHIFTS FOR MOLECULAR ORIENTATED SOLID POLY (ETHYLENE TEREPHTHALATE)

本文从已知的聚对苯二甲酸乙二醇酯(PET)的X-射线原子坐标和化学位移张量主值出发,计算了拉伸的PET样品,相对于外磁场不同放置方位下的^(13)C-NMR谱峰的化学位移值,很好地解释了实验结果,并得到了拉伸条件下,高聚物中分于取向的信息。

Based on the atomic coordinates determinated by X -ray diffraction and the principal values of ~13C-NMR chemical shifts, we introduced an approach to calculate the chemical shifts of orientated PET. The direction of drawing axis of PET was parallel to the direction of magnetic field. The calculated results fit the experimental data very well. Thus, we get the conclusion that the main direction of molecular chain is parallel to the drawing axis.