【作者】 王军利；

【导师】 刘忠； 陈夫山；

【作者基本信息】 天津科技大学 ， 制浆造纸工程， 2002， 硕士

【摘要】 瓜耳胶作为一种从瓜耳豆中提取的植物胶，具有天然、环保、易溶于水等优点。目前它主要应用于卷烟纸等高附加值纸种，增强效果明显而留着效果较差。在此基础上通过醚化剂改性得到的阳离子瓜耳胶，在保持其增强作用的同时大幅度提高了助留效果，而且能够保持或改善纸页匀度。 本实验用溶剂法制备阳离子瓜耳胶，溶剂法具有反应效率高，产品质量好，操作方便等优点。反应体系中适量水的存在可以使瓜耳胶发生润胀，提高反应效率和均一性。实验结果发现水/溶剂在在1.05到1.80左右，反应产物取代度保持较高水平。碱在反应体系中起重要的作用，一方面它作为反应物被消耗，另一方面它起催化剂的作用以提高反应速率。另外，必须保证有过量的碱使得醚化剂分子变成反应活性很高的环氧结构。醚化剂的用量也是影响反应产物取代度和反应效率的重要因素，实验研究还发现，醚化剂与NaOH之间存在较强的相互作用，碱与醚化剂的摩尔比在1.4～1.6范围内时，反应效率最高。反应液比从反应效率和可操作性考虑选3.1:1左右较为适宜。反应初期温度对反应影响不是很大，温度在40-50℃为较好，不宜太高。保温温度越高，达到一定取代度的反应时间越短。反应的高温保温时间不宜超过4小时，时间过长会导致已经接上的季铵基团重新脱落。不同溶剂制备的反应产品取代度由大到小为：无水乙醇＞工业酒精＞甲醇，异丙醇在实验确定的水/溶剂比列下难以进行。反应结束后应调节pH值在中性或弱碱性，反应中搅拌条件对产品取代度影响很小。另外，对四个影响因子的正交实验结果表明，其对反应影响的重要程度依次为：醚化剂用量＞用碱量＞碱与醚化剂的交互作用＞反应温度＞水/溶剂。 阳离子瓜耳胶的应用效果受浆料种类、剪切力和填料的种类、用量等许多因素的影响。阳离子瓜耳胶用于漂白硫酸盐木浆加滑石粉系统作助留助滤剂时，从助留、助滤和增强三方面综合考虑，0.05％的用量较为适宜，pH值最好控制在7左右，阳离子瓜耳胶取代度不宜超过0.1，适量硫酸铝的加入可以提高留着效果。在相同成本下应用三种助剂，助留助滤效果依次为：CGG＞CPAM＞CS。另外本文还对阳离子瓜耳胶与阳离子淀粉的预先混合使用作了初步的探索。阳离子瓜耳胶应用于卷烟纸浆加碳酸钙系统的研究结果表明，0.1％的CGG用量时，打浆度下浆最多。无论是静态的手抄片实验还是动态滤水实验，0.07％的阳离子瓜耳胶用量都使留着率最好。由于碳酸钙填料的使用，留着和滤水都在偏碱性条件下效果较好，pH值为8时最佳。另外，阳离子取代度也不宜超过0.1。更多还原

【Abstract】 As a vegetable gum distilled from guar beans, guar gum is a natural, environmental friendly and water-soluble substance. At present, it is mainly used in the kind of paper with high profit margin, such as cigarette paper. It has a good performance in enhancing the strength of sheet while has a poor retention effect. The cationic guar gum derived from it by reacting with etherifying agent can increase its retention effect dramatically with its strengthening potential. Furthermore it will maintain or improve the formation of the paper.Solvent method is used for the preparation of cationic guar gum. The advantages of solvent method include high reaction efficiency, good quality of product and convenient operation etc. A proportion of water in the reaction system is beneficial, it can make guar gum swell so that the efficiency and uniformity of the reaction are improved. It was found that a ratio of water/solvent from 1.05 to 1.80 resulted in fairly high DS of the product. Alkali plays a big role in the etherification. First it is consumed as a reactant, on the other hand, it functions as a catalyst to increase the reaction rate. Additional alkali should exist in the reaction system to convert the molecule of etherifying agent into epoxy ammonium salt which has a high reaction activity. The amount of etherifying agent is another important influencing factor. We also found that there is a strong inter-reaction between etherifying agent and alkali. A ratio of alkali/etherifying agent from 1.4 to 1.6 is suitable to produce CGG with high DS. For consideration of both reaction efficiency and operation, liquor ratio about 3.1:1 is ideal. The temperature at the beginning of the reaction does not influence very much. 40-50℃ will do and too high temperature is not recommended for the alkalization of guar gum lets out heat. To achieve a given DS, higher temperature often means shorter reaction time. Reaction at high temperature as 70-80 ℃ should not last too long. Four hours is sufficient and after that ammonium base which has already boned with guar gum may lose. The DS of CGG prepared with different solvents follows: ethanol absolute> industrial alcohol> methanol, iso-propyl alcohol proved to be inoperable under the water/solvent ratio determined by the experiment. After reaction the system should adjust the pH to 7. Stirring speed is not vital for the reaction and the importance sequence of different factors is: amount of etherifying agent> amount of alkali > inter-reaction between the above two > temperature > water/solvent ratio.Application effect of cationic guar gum is affected by many factors including composition of pulp, shearing force, dosage and sort of filler etc. We did a research in the use of cationic guar gum in bleached Kraft + talc furnish. When functioning as a retention and drainage aid, a dosage of 0.05%(based on oven pulp) of CGG is suitable considering three aspects of retention, drainage and strengthening. pH value should be controlled at 7 or so. Degree of substitution no more than 0.1 is all right. A proper amount of alum could improve the retention rate. Three different additives were applied on the base of equal cost, and the effectivity in retention and drainage is the following: CGG>CPAM>CS. Besides, we also did a primary research in the use of a blend comprising of cationic guar gum, cationic starch and a certain organic acid. In another system composed of cigarette pulp and CaCOs the best drainage effect was obtained at a dosage of 0.1 % of CGG. Whether from the handsheet test or dynamic drainage jar, retention rate got the highest at a dosage of 0.07% of CGG. Because of the use of CaCOs, drainage and retention are all much better under alkalescent surrounding than acidic system. pH value of 8 is the best choice. Further more, DS no more than 0.1 is also recommended.更多还原