机械活化预处理甘蔗渣制备醋酸纤维素的工艺  

Preparation technology of cellulose acetate from sugarcane bagasse by mechanical activation

作　　者：陈渊[1] 黄祖强[2] 杨家添[1] 朱万仁[1] 莫建华[1] 刘利雁[1] 

机构地区：[1]玉林师范学院化学与生物系,玉林537000 [2]广西大学化学化工学院,南宁530004

出　　处：《农业工程学报》2010年第9期374-380,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：广西自然科学基金(0640006);广西大学科研基金(X071025)

摘　　要：为开发利用甘蔗渣,制备高取代度的醋酸纤维素,该文采用自制搅拌磨对甘蔗渣进行机械活化预处理,以不同活化时间的甘蔗渣为原料,醋酸酐作为乙酰化剂,浓硫酸为催化剂,制备醋酸纤维素。以醋酸纤维素的取代度为评价指标,分别探讨机械活化时间、反应时间、反应温度、催化剂用量、液固比等因素对甘蔗渣乙酰化反应的影响,并在此基础上采用正交试验确定制备工艺的最佳条件。结果表明,机械活化对甘蔗渣乙酰化反应具有显著的强化作用,经机械活化预处理后的甘蔗渣比原甘蔗渣更容易进行乙酰化反应。主要的原因是机械活化破坏了甘蔗渣中木素对纤维素的包裹作用,结晶结构受到破坏,降低纤维素的结晶度,乙酰化试剂更容易渗透到甘蔗渣内部使纤维素发生乙酰化反应,降低了对反应时间、反应温度、催化剂用量、液固比的依赖性,提高了反应活性。以活化60min的甘蔗渣为原料进行乙酰化反应,在液固比为12mL/g,催化剂质量分数为4%,反应温度为60℃,反应时间为3.0h的条件下,可制得取代度为2.81的醋酸纤维素。并采用红外光谱(IR)、扫描电镜(SEM)、X-射线衍射(XRD)对甘蔗渣醋酸纤维素的结构进行了表征。研究结果将为制备高取代度醋酸纤维素提供依据和基础数据。To utilize sugarcane bagasse and prepare cellulose acetate of high degree of substitution,sugarcane bagasse （SCB） was mechanically activated by a stirring-type ball mill.Using acetic anhydride as esterification agent and concentrated sulfuric as catalyst,cellulose acetate （CA） was synthesized from sugarcane bagasse with different activation times.The effects of mechanical activation time,reaction time,reaction temperature,amount of catalyst and solid-liquid ratio on esterification of sugarcane bagasse were investigated respectively by using degree of substitution （DS） of cellulose acetate as evaluating parameter.The best conditions of preparation technique were confirmed by anorthogonal test.The results indicated that mechanical activation considerably enhanced the acetylation of sugarcane bagasse.Mechanical activated sugarcane bagasse was easier acetylation than the original sugarcane bagasse.Due to mechanical activation broken the sealing of cellulose by lignin,destroyed the crystalline structure,decreased the degree of crystallinity of cellulose,which made esterification reagent more easily penetrate into the sugarcane bagasse internal.It could increase reactivity and decrease the dependence of reaction time,reaction temperature and amount of catalyst.The degree of substitution of cellulose acetate was 2.81 by acetylation of mechanical activated sugarcane bagasse for 1.0 h and reaction in the conditions of liquid-solid ratio12 mL/g,mass fraction of catalyst 4%,reaction temperature 60℃ and reaction time 3.0 h.The structure of cellulose acetate from sugarcane bagasse were characterized by using infrared spectroscopy （IR）,scanning electron microscopy （SEM） and X-ray diffraction （XRD）.The results would provide a base and data for the preparation of cellulose acetate of high degree of substitution.

关 键 词：乙酰化 红外光谱 扫描电镜 甘蔗渣 醋酸纤维素 机械活化 

分 类 号：O636.11[理学—高分子化学]