【作者】 吉毅；

【导师】 李宗石；

【作者基本信息】 大连理工大学 ， 应用化学， 2005， 硕士

【摘要】 瓜尔胶是环境友好的水溶性高分子材料,其主要成分为半乳甘露聚糖,结构是由D-甘露糖通过β-1,4糖苷键链接形成主链,在某些甘露糖上D-半乳糖通过α-1,6糖苷键链接形成侧链而构成多分枝的聚糖,通常半乳糖与甘露糖的摩尔比为1:2,由于瓜尔胶溶解速度慢,水不溶物含量高,黏度不易控制,因此需要对它进行化学改性,扩大其应用领域。首先以瓜尔胶和环氧丙烷合成了羟丙基瓜尔胶,用核磁共振和红外光谱表征了羟丙基瓜尔胶的结构,并用分光光度计法测定了羟丙基瓜尔胶的取代度。以水不溶物和黏度为指标进行了系统的研究,确定了最佳工艺条件,改性后的羟丙基瓜尔胶水不溶物由原来的12%降为5%以内,黏度则下降不是很大,1%的水溶液黏度为2000-2500mPas,交联性能和未改性的瓜尔胶相当,产品性能达到了要求,并大大降低了成本。为了制备阳离子瓜尔胶,合成了3-氯-2-羟丙基三甲基氯化铵阳离子醚化剂,用IR、NMR、MS和DSC等方法对其结构进行了表征,并优化了反应条件。以此阳离子中间体制备了瓜尔羟丙基氯化铵。以含氮量为指标,考察各因素的影响,确定了最优工艺条件,瓜尔羟丙基氯化铵的含氮量达到0. 6%,取代度达到0. 54,黏度基本未变,灼烧残余控制在6%以内。本论文还研究了两性离子瓜尔胶,以磷酸盐和瓜尔胶反应,首先制得了瓜尔胶磷酸酯,然后再和3-氯-2-羟丙基三甲基氯化铵反应合成了两性离子瓜尔胶,此产物中阴阳离子取代基可能位于同一链节上,也可能位于不同的链节上,所得产物的等电点为pl=6. 3-6. 6。为了得到阴阳离子取代基位于同一链节上的类磷脂瓜尔胶,合成了3-氯-2-羟丙基磷酸酯盐和磷酸酯基甜菜碱两种中间体。通过质谱、核磁共振和红外光谱验证了化合物的结构,以磷酸酯基甜菜碱中间体和瓜尔胶反应制取类磷脂瓜尔胶,以取代度为指标确定了最优工艺条件。类磷脂瓜尔胶的等电点pI=7. 4-8. 6。所得产物具有较强的耐盐性。更多还原

【Abstract】 Guar gum, a water-soluble natural polymer, is composed mostly of ploygalactomannans which is essentially a straight chain mannan with single membered galactose branches. The mannose units are linked in a l-4-.beta.-glycosidic linkage and the galactose branching takes place by means of a 1-6 linkage on alternate mannose units. The ratio of galactose to mannose in the guar polymer is, therefore, one to two. Guar gum is often chemically modified to improve its physical and chemical properties, so that it can be used as thickeners for foods, paints, oil well fluids, personal care products, and many other functional applications.Hydroxypropyl guar gum (HPG) is prepared by the reaction of guar gum with propylene oxide. NMR and IR are used to characterize the structure of HPG; spectrometry is also used to determine molar substitution. The synthetic procedure was studied as the base of the content of insoluble residue and the viscosity, them the best technical conditions were determined. Comparing with original guar gum, HPG remains its viscosity and cross linking ability, and considerably decrease its content of insoluble residue. The cost of production has been decreased greatly.In order to prepare cationic guar gum, the cationic etherifying agent 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride (CHPTMA) was synthesized firstly. The structure of CHPTMA was confirmed by IR, MS, NMR and DSC, and the optimum conditions were determined. Then, cationic guar gum was synthesized with the cationic etherifying agent CHPTMA and guar gum by organic solvent process. All kinds of influence factors are studied in detail, and the optimum conditions were determined. The modified cationic guar gum remains its viscosity, and has low burn residue and high content of nitrogen.In this paper, amphoteric guar gum was also studied, there are two synthetic routes. First phosphate anionic guar gum was prepared; afterwards amphoteric guar gum was synthesized with the cationic etherifying agent CHPTMA and phosphate anionic guar gum, in this product, maybe the anionic and cationic substituents are at the same chain link or at the different chain link, its isoelectric zone is 6.3~6.6. In order to get the amphoteric guar gum that the anionic and cationic substituents are at the same chain link, 3-chloro-2- hydroxypropyl phosphate and phosphobetaine were synthesized. The structure of these two compounds was confirmed by MS, IR, and NMR, and then amphoteric guar gum was synthesized with the amphoteric intermediate phosphobetaine and guar gum, and the optimum technological conditions were determined. Its isoelectric zone is 7.4~8.6, and has good salt tolerance.更多还原