催化剂在木质纤维素液化中应用的研究进展

木质纤维素是最丰富的可再生资源之一,具有低污染,广泛分布等优点,在化石资源日益枯竭的背景下,将其转化为高附加值化学品,为工业原料和能源油料提供可替代的资源是当前研究的一个热点,具有广阔的发展前景。文中详细综述了近年来国内外在木质纤维素液化中使用的催化剂类型、作用和研究进展,主要介绍了以浓硫酸为代表的液体无机酸,以NaOH为代表的固体无机碱,以草酸为代表的有机酸,以AlCl_3为代表的盐类和以Cl-/Fe_2O_3为代表的固体杂多酸;同时,分析、对比了不同类型催化剂的优点和缺点,预测了未来木质纤维素液化催化剂的发展趋势和前景。     

Biosorption of methylene blue by chemically modified cellulose waste

Citric acid modifi ed cellulose waste（CMCW） was prepared via esterifi cation and used as a low-cost biosorbent for the removal of methylene blue（MB） from aqueous solutions. The effects of biosorbent concentration, initial pH of MB solution, biosorption temperature, contact time, and initial MB concentration on the biosorption of MB were investigated using batch biosorption technique under static conditions. The experimental results showed that CMCW exhibited excellent biosorption characteristics for MB. The maximum biosorption capacity of MB was up to 214.5 mg/g at an adsorption temperature of 293 K. The removal rate of MB onto CMCW reached the maximum at pH〉4 and the biosorption reached an equilibrium at about 50 min. The kinetic data can be described well with the pseudo-second-order model and the isotherm data was found to fi t the Langmuir isotherm with a monolayer adsorption capacity of 211.42 mg/g. The biosorption appears to be controlled by chemisorption and may be involved in surface adsorption and pore diffusion during the whole biosorption process.     

哌嗪改性木质素/磷酸铝双重包覆红磷的制备与阻燃性能

以哌嗪改性木质素(LP)和磷酸铝为囊材,制备了具有多层次阻燃性能的无卤微胶囊化红磷阻燃剂,并用于改善丙烯腈-丁二烯-苯乙烯(ABS)树脂的阻燃性能。利用透射电子显微镜、扫描电子显微镜、红外光谱和热重分析等测试手段对阻燃剂的形貌和结构进行了表征,研究了阻燃剂添加量对ABS阻燃性能的影响。结果表明,红磷被LP和磷酸铝严密包覆;添加25%阻燃剂的ABS复合材料燃烧后可形成致密、厚实的残炭层,阻燃级可达到UL94 V-0等级,极限氧指数达到26.1%。与未添加阻燃剂ABS树脂相比,热释放速率峰值降低了63.1%,总烟雾释放量降低了25.8%。     

木质素液化多元醇改性酚醛树脂胶粘剂的合成与性能

以聚乙二醇400为主液化试剂,丙三醇为辅助液化剂,浓硫酸为催化剂对酶解木质素进行液化,得到了酶解木质素液化多元醇,将其替代部分苯酚与甲醛合成了改性酚醛树脂胶粘剂。采用红外光谱对酶解木质素液化多元醇和改性胶粘剂的结构进行了表征和分析,并对胶粘剂的性能进行了测定。结果表明,当酶解木质素液化多元醇替代苯酚的质量分数为10%-25%时,胶粘剂的固含量、pH值、胶合强度、游离醛含量和游离酚含量都能满足国标GB 9846.1-12-88的要求,且液化多元醇添加量增大时,固含量升高,pH值降低,湿强度先降低而后增大,干强度先增大而后快速降低。     

Optimisation of Bio-polyol Production from Cassava Residue Using Ethylene Glycol as the Liquefaction Reagent

Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 130-170 ℃ with sulfuric acid as the catalyst. The influences of liquefaction parameters, such as the type of liquefaction reagents, mass ratio of EG/cassava residue, liquefaction temperature and time on the properties of the products were discussed. The optimum liquefaction conditions were obtained when the mass ratio of EG/cassava residue was 6:1(w/w), the liquefaction temperature was 150 ℃, the liquefaction time was3 h and the mass fraction of concentrated sulfuric acid/EG was 2.5 wt%. The hydroxyl numbers and residue content of the liquefied products at optimal conditions were 1 137 mgKOH/g and 0.43%, respectively. FT-IR spectrum showed that the liquefaction product of cassava residue was polyether polyol and could be used to prepare polyurethane material or alkyd resins.     

Fe3O4纳米粒子的制备及微量热应用研究

采用化学共沉淀法制备出了可达到纳米级分散的Fe3O4纳米粒子,讨论了产物的结构,粒径分布、磁性能及制备过程中工艺条件的控制,并利用等温微量热检测仪测量了Fe3O4和油酸-乙醇溶液之间的吸附热,分析了两者之间的吸附机理.     

微悬浮聚合法制备聚苯乙烯磁性微球的研究

将油酸表面改性后的F e3O4纳米颗粒均匀分散在苯乙烯中,并采用微悬浮聚合方法合成了用于生物功能材料的聚苯乙烯磁性微球,得到较好的球状产物,粒径范围在15μm~25μm,该磁性微球具有较好的磁性能和超顺磁性。微球的形貌、粒径及其分布和磁性能分别采用扫描电镜、红外光谱、磁强计等进行了表征。     

Preparation,Characterization, and Performance of Lignin-based Microencapsulated Red Phosphorus Flame Retardant for ABS

The inherent difficulty in preservation and processing of conventional red phosphorus flame retardant severely limits its growing applications in polymer materials,thus,there is an urgent need to exploit effective technology to modify red phosphorus.Functionalized lignin-based compounds can provide a great potential in improving the preservation and processing of red phosphorus.Here,we prepared melamine modified lignin/aluminum phosphate coated red phosphorus (LMAP@RP) and used it as the flame r...     

新型聚氨酯助剂——酶解木质素的研制

研究了采用无机碱性水溶液和有机溶剂从玉米秸秆发酵制备乙醇的残渣中分离得到酶解木质素的方法.结果表明,用有机溶剂提取后的残渣继续用无机碱水溶液再次提取,酶解木质素的产率为25%～35%,其红外光谱与磨木木质素红外光谱相似.酶解木质素的分子中含有丰富的苯环、酚羟基和醚键等官能团,具有较高的反应活性,能直接用于聚氨酯的改性.     

磁性螯合树脂的悬浮缩聚合成及吸附性能研究

用聚乙烯醇作分散剂，以γ-Fe2O3磁粉为载体、通过聚环氧氯丙烷与己二胺进行悬浮缩聚反应,合成了一种新型的磁性螯合树脂．并研究了它对过渡金属离子的吸附性能。结果表明，该种树脂在pH=4～6的酸度范围内对Cd^2 和Pb^2 等金属离子有良好的吸附性。对混合离子的吸附性能也进行了研究．各金属离子吸附性能有所不同,表明多种金属离子的同时存在对各自的吸附有相互干扰作用。