Abstract

Interactions between the hierarchical structure of Japanese cypress and small hydroxylic solvents with high polarity were studied using variable-temperature ¹³C cross-polarization and magic-angle spinning nuclear magnetic resonance (CP/MAS) NMR spectroscopy, including low-temperature measurements. ¹³C CP/MAS NMR spectra were enhanced by dipolar interactions closely related to ¹H–¹³C magnetization transfer, providing information about the interaction between woody materials and small hydroxyl molecules. The change in interaction was particularly near the melting point of the hydroxylic solvent, where a decrease in the intensity of the cypress carbohydrate signal and the appearance of the signal of solvent molecules were observed. The trend of signal intensity in the variable-temperature ¹³C CP/MAS NMR spectra of cypress and cellulose fibers in the presence of hydroxylic solvents indicated that the decrease in the carbohydrate signal intensity due to the transfer of magnetization near the melting point of the hydroxyl molecule is greater when the size of the hydroxyl molecule is smaller. Furthermore, molecular association in the nanopores of the hierarchical structure allowed the hydroxyl molecular signals of the impregnated cypress to appear above the melting point.

摘要

使用变温¹³ C 交叉极化和魔角旋转核磁共振 (CP/MAS) NMR 光谱（包括低温测量）研究了日本柏树的分级结构和高极性小羟基溶剂之间的相互作用。^{13 C CP/MAS NMR 谱通过与1} H– ¹³密切相关的偶极相互作用得到增强C磁化转移，提供有关木质材料和小羟基分子之间相互作用的信息。相互作用的变化特别接近羟基溶剂的熔点，其中观察到柏树碳水化合物信号强度的降低和溶剂分子信号的出现。变温情况下信号强度的变化趋势¹³羟基溶剂存在下柏树和纤维素纤维的 13 C CP/MAS NMR 谱表明，当羟基分子尺寸较小时，由于羟基分子熔点附近磁化强度的转移而导致碳水化合物信号强度的降低更大。较小。此外，分层结构的纳米孔中的分子缔合使得浸渍柏树的羟基分子信号出现在熔点以上。