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本研究通过先超声预处理再常温稀碱抽提的两步法,成功地由玉米芯中分离得到水不溶性半纤维素(HA)和水溶性半纤维素(HB),并探讨了在不同的碱浓度下超声预处理对获得的半纤维素的得率和结构的影响。结果表明,先经过10 min的超声预处理,再经3 h 5.0%KOH常温抽提得到半纤维素的得率与不经过超声预处理的20 h常温稀碱抽提大致相同,但采用前一种方法得到的水溶性半纤维素的得率较后一种方法大为提高。此外,离子色谱(IC)、凝胶渗透色谱(GPC)、傅里叶变换红外光谱(FT-IR)和核磁共振氢谱(1H-NMR)的表征结果表明,与传统稀碱抽提所得的半纤维素相比,经过短时间超声预处理和相同浓度的稀碱液抽提后,水溶性半纤维素中的阿拉伯糖含量更高,由此说明半纤维素分子链中更多的支化结构得以保留,而该结构的存在将对后续的改性反应更为有利。
In this study, water-insoluble hemicellulose (HA) and water-soluble hemicellulose (HB) were successfully separated from corncob by two-step ultrasonic pretreatment followed by normal-temperature dilute alkali extraction. Effect of Ultrasound Pretreatment at Base Concentration on Yield and Structure of Hemicellulose Obtained. The results showed that the yield of hemicellulose extracted by ultrasonic pretreatment at 10 min for 3 h and 5.0% KOH at room temperature was approximately the same as that of 20 h at room temperature without ultrasonic pretreatment. However, The yield of water-soluble hemicellulose obtained by this method is much higher than that of the latter method. In addition, the characterization results of ion chromatography (IC), gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance spectroscopy (1H-NMR) Compared with hemicellulose, the content of arabinose in water-soluble hemicellulose is higher after a short time ultrasonic pretreatment and the same concentration of dilute lye, thus indicating more branching in the hemicellulose molecular chain Structure is retained, and the existence of the structure will be more favorable for the subsequent modification reaction.