白酒丢糟制备微晶纤维素工艺优化及结构特性

Optimization of Preparation Conditions and Structural Properties of Microcrystalline Cellulose from Distillers Grains

白酒丢糟(DG)是一种富含纤维素的木质纤维素生物质,为充分转化利用丢糟资源,探索其制备药用辅料微晶纤维素(MCC)的可行性。从丢糟中提取出高纯度纤维素,采用稀盐酸水解法制备丢糟微晶纤维素(DGMCC),考察了盐酸浓度、时间、温度和料液比等因素对产品聚合度和得率的影响,并通过正交实验优化制备工艺。结果表明,从丢糟中提取的纤维素纯度为94.55%;丢糟纤维素在料液比为1:15(g/mL)、盐酸浓度为6%(V/V)、温度为70℃的最优条件下水解60 min可制得聚合度为288的DGMCC产品,得率为27.01%。利用FTIR、SEM、XRD、TGA和DSC等手段对DGMCC微观形貌、结晶结构和热稳定性进行表征。FTIR说明DGMCC的主要成分为纤维素;SEM和XRD表明DGMCC呈不规则球形颗粒,纤维素晶型为Ⅰ型,相对结晶度为62.47%,晶粒尺寸为54.95 nm。TGA和DSC表明DGMCC在365.3℃处有一尖锐的结晶熔融吸热峰,初始热分解温度高于原料DG,热稳定性好。

Distillers grain （DG） is a kind of lignocellulosic biomass with high content of cellulose. In this study, the feasibility of preparing microcrystalline cellulose （MCC） by DG was observed. Dilute hydrochloric acid hydrolysis was carried out to prepare DGMCC. The prepared DGMCC samples were then characterized by FTIR, SEM, XRD, TGA and DSC, comparing with that of DG and commercial MCC （Lowa？PH101）. The fineness of cellulose was 94.55%. The optimum conditions for the preparation of DGMCC were solid-liquid ratio of 1：15 （g/mL）, hydrochloric acid concentrations of 6% （V/V）, temperature of 70 ℃ and time of 60 min, under which the DP and the yield of DGMCC were 288 and 27.01%, respectively. FTIR spectroscopy showed that the main component of DGMCC was cellulose. SEM and XRD indicated that the DGMCC samples appeared an irregular but overall spherical shape, the crystallinity and particle sized of which was 62.47% and 54.95 nm, respectively. In addition, TGA and DSC revealed a sharp endothermic peak at 365.3 ℃. In a word, DGMCC particles showed higher thermal stability than that of DG and similar structural properties to Lowa？PH101.