综纤维素氢键模式的研究

Research on Hydrogen Bonding Patterns of Holo-cellulose by XRD and FT-IR

用广角X射线衍射(XRD)和红外光谱(FT-IR)的高斯函数分峰拟合法研究了桉木浆综纤维素稀酸水解去除无定形区过程中晶型和氢键模式的变化。研究结果表明,稀酸水解前后,纤维素的结晶度和晶面尺寸增大,桉木浆综纤维素、盐酸水解桉木浆综纤维素和硫酸水解桉木浆综纤维素中分子间氢键的相对含量分别为48.15%、77.07%、55.22%,证实纤维素链间主要靠分子间氢键结合,稳定纤维素链;分子内氢键处于辅助地位。稀盐酸水解纤维素无定形区前后,分子内氢键的强度分别从10.05%下降到4.19%,41.78%下降到18.74%,分子间氢键的强度则从48.15%上升到77.07%。稀硫酸水解纤维素无定形区前后,分子内氢键强度分别从10.05%下降到7.63%,41.78%下降到37.15%,分子间氢键强度则从48.15%上升到55.22%。稀酸水解前后,纤维素的晶型不变,只是发生氢键类型的相互转化。

The change of crystalline form and hydrogen bonding patterns of holo-cellulose during dilute acid hydrolysis process was analyzed by X-ray diffraction and FF-IR spectroscopy. The FT-IR spectra of hydrogen-banded OH stretching vibration were resolved into three bands for cellulose I, assuming that all the vibration modes follow Gaussion distribution. Results showed that the crytallinity of cellulose and crystal- lite size increase after hydrolysis treatment. The relative contents of molecular hydrogen in three kinds of samples are 48.15% , 77.07% and 55.22%. It has been proved that cellulose chains mainly combine together by hydrogen bonding between molecules, while intramolecular hydrogen bonds are taking second place. Acid hydrolysis only influences the transformation of hydrogen bonding patterns while crystalline form has no change.