【作者】 聂宗利；

【导师】 武玉民；

【作者基本信息】 青岛科技大学 ， 化学工程， 2011， 硕士

【摘要】 阳离子聚丙烯酰胺因含有阳离子基团而具有特殊功效,是目前功能高分子研究领域的热点之一。水分散聚合技术具有反应过程简单,不使用有机溶剂等优点,是制备聚丙烯酰胺的一种环境友好型新技术。水分散聚合体系中的分散稳定剂是影响分散聚合过程的关键因素,对分散聚合有着重要的影响,而目前水分散聚合应用的分散剂大多集中在人工合成的均聚物或共聚物,对天然高分子聚合物的应用鲜见报道。本论文将天然高分子聚合物——壳聚糖作为新型分散剂引入到阳离子聚丙烯酰胺水分散体系中,对该环境友好型水分散阳离子聚丙烯酰胺的制备规律进行了细致的研究,通过多种表征方法详细表征了聚合物的结构,并且探讨了壳聚糖/阳离子聚丙烯酰胺产品的絮凝性能。1.以壳聚糖(Cts)为分散剂,丙烯酰胺(AM)和阳离子共聚单体甲基丙烯酰氧乙基三甲基氯化铵(DMC)为主要单体原料,选择水溶性偶氮化合物(V50)为引发剂,在氯化钠的弱酸溶液中采用水分散聚合制备了稳定的Cts/CPAM聚合物。2.在弱酸条件下(pH = 5.5)系统考察了单体用量、单体配比AM/DMC(质量比)、分散剂用量、无机盐用量、引发剂用量、反应温度等因素对水分散聚合反应、产品特性(分子量)和体系稳定性的影响。3.通过正交试验法确定了较佳的合成工艺条件:分散剂用量为1.50 %,无机盐的用量为17.50 %,引发剂用量为0.042‰,反应温度为60.0℃。4.利用红外光谱(FTIR)、X射线衍射(XRD)、扫描电镜(SEM)、热失重(TGA)等分析方法对聚合物产品进行了表征,从微观角度对产品的结构性质进行了细致的研究。结合前面单因素实验分析,可以推测壳聚糖作为分散剂时,在AM与DMC聚合的过程中,壳聚糖也接枝到聚合物分子中,使体系产生了一种自稳定的分散作用。该方法制备的聚合物颗粒细小、分布均匀,热性稳定性能较高。5.以质量分数为1‰的高岭土模拟废水进行絮凝实验,系统考察了水分散型Cts/CPAM的投加量、温度等因素对絮凝性能的影响。实验表明:该聚合物具有投加量少、絮凝性能良好的特点,而且聚合物的絮凝效果受pH变化的影响较小,对温度不敏感,因此该聚合物具有较广的使用范围。6.通过分析絮体的结构特征,探讨了聚合物的絮凝机理。实验结果表明:聚合物处理高岭土模拟废水所产生的絮体具有较明显的分形特征,微絮体与絮凝聚集体之间的吸附架桥现象明显。更多还原

【Abstract】 Cationic polyacrylamide with cation group could prove significant special effects, so it had been one of the hot researchs in the main researeh areas of functional polymers. Aqueous dispersion polymerization was a new excellent method which had many advantages such as simplicity in process, solvent-free and so on. The stabilizer was important to the aqueous dispersion polymerization as the key factor in the system, the most commonly used stabilizers were synthetic copolymers and homopolymers; but the natural polymers was not reported. In the thesis, chitosan(Cts) was introduced into aqueous dispersion polymerization of cation polyacrylamide as new dispersant. The preparation of environment-friendly aqueous dispersion of cationic polyacrylamide were detailedly investigated. The structure of copolymer was characterized by various methods. Meanwhile, the performances of the coagulation-flocculation were discussed.1. This research selected chitosan as dispersant stabilizer, acrylamide(AM) and cationic monomer dimethylaminoethyl methacrylate methyl chloride (DMC) as main raw materials, and azo-compounds(V50) as initiator, the cationic polyelectrolyte of Cts/CPAM was synthesized by aqueous dispersion polymerization in the sodium chloride solution with weak acid.2. The effects of varying factors on the polymerization, the product character (i.e. molecular weight) and the stability of the system were investigated including the dosage of monomers, dispersant, sodium chloride and the dosage of initiator, the mass ratios of AM/DMC, the reaction temperature and so on.3. By the orthogonal experiment, the optimum conditions of synthesis were determined as follows, the dosage of dispersant 1.50 %, the concentration of inorganic salt 17.50 %, the concentration of initiator 0.042‰and the react temperature 60.0℃. 4. The dispersion copolymers were characterized with Fourier Transform Infra-Red (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetry analysis (TGA). The property of the copolymer was researched with microscopic viewpoint. Combined with previous discussion of the single factor experiment, it was speculated that Cts was grafed to the copolymer of AM and DMC in the reaction process, making the system generated self-stabilization. And the copolymer particles were smaller and homogeneous, its thermal stability was good.5. The high molecular weight Cts/CPAM was used as flocculant to treat kaolin waste water. The influences of the concentration of the copolymer, the temperature and stirring rate etc. on the flocculation efficiency were investigated. It was found that the dosage was few, but the flocculating effect was good. In addition, the flocculating property had the advantages, such as small pH effeet and wide temperature range.6. The flocculating mechanism of the copolymer was discussed based on the floc form. The results illustrated that the flocs of kaolin treated by the coplymer had obviously features of fractal, and the performance of absorbing and bridging was well between microflocs and flocculated aggregates.更多还原