通过¹³C和¹H固态核磁共振对聚酰亚胺进行表征。
Characterization of polyimides by 13C and 1H solid state nuclear magnetic resonance.
作者信息
Varner S J, Vold R L, Hoatson G L
机构信息
Department of Physics, College of William and Mary, Williamsburg, VA 23187-8795, USA.
出版信息
Solid State Nucl Magn Reson. 1998 Sep;12(2-3):71-85. doi: 10.1016/s0926-2040(98)00054-x.
The polyimides LaRC-TPI, LaRC-IA and LaRC-SI and related model compounds were investigated using 13C and 1H nuclear magnetic resonance (NMR). Magic angle spinning was used to acquire 13C isotropic chemical shift spectra of these materials. The spectra were assigned as completely as possible. In addition, the principal components of some shielding tensors were measured using variable angle correlation spectroscopy (VACSY). Of those studied, LaRC-SI is the only polymer that is soluble. However, after it is heated past its glass transition temperature, LaRC-SI becomes insoluble. Experiments were performed in an attempt to identify causes of this behavior. When magnetization from nuclei in rigid regions of the polymer is suppressed, the 1H and 13C NMR spectra of soluble LaRC-SI are significantly different from those of insoluble LaRC-SI. Hydration studies of LaRC-SI show that absorbed water plasticizes the polymer.
使用碳 - 13（13C）和氢 - 1（1H）核磁共振（NMR）对聚酰亚胺LaRC - TPI、LaRC - IA和LaRC - SI以及相关模型化合物进行了研究。采用魔角旋转来获取这些材料的13C各向同性化学位移光谱。尽可能完整地对光谱进行了归属。此外，使用可变角度相关光谱学（VACSY）测量了一些屏蔽张量的主成分。在所研究的材料中，LaRC - SI是唯一可溶的聚合物。然而，当加热超过其玻璃化转变温度后，LaRC - SI变得不可溶。进行了实验以试图确定这种行为的原因。当聚合物刚性区域中原子核的磁化被抑制时，可溶的LaRC - SI的1H和13C NMR光谱与不可溶的LaRC - SI的光谱有显著差异。LaRC - SI的水化研究表明，吸收的水分使聚合物发生了增塑。
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