【作者】 王传兴；

【导师】 武玉民；

【作者基本信息】 青岛科技大学 ， 化学工程， 2010， 博士

【摘要】 功能型聚丙烯酰胺（PAM）是当今材料领域的研究热点之一。两性聚丙烯酰胺（AmPAM）属于一种典型的两性聚电解质,因具有特殊的性能而备受关注。水分散聚合是当今水溶性高分子领域的最新技术,聚合反应可在温和条件下进行,同时避免了有机溶剂的二次污染问题。本文以丙烯酰胺（AM）为主要原料,丙烯酸（AA）为阴离子单体,甲基丙烯酰氧乙基三甲基氯化铵（DMC）为阳离子单体,以硫酸铵为相分离剂,DMC均聚物为分散稳定剂,以2,2-偶氮双（2-甲基丙脒）盐酸盐（V-50）为引发剂,采用分散聚合技术合成了同时具有阴、阳离子基团的两性聚丙烯酰胺。探讨了硫酸铵浓度、稳定剂浓度、稳定剂分子量、单体浓度、单体类型、引发剂浓度、氯化钠浓度、离子度、pH值和温度对分散聚合过程的影响,通过核磁共振氢谱、元素分析等分析手段对聚合物的分子结构进行了表征。在制备工艺中引入种子分散聚合技术,获得了高活性物含量的两性聚丙烯酰胺水分散体系。借助于两性聚合物特性粘数、分子量的表征,优化了相应的计算公式,并对分散聚合反应动力学进行了研究。利用HAAKE流变仪、RheolabQC粘度计等手段,研究了两性聚丙烯酰胺分散体系的稀释溶胀性,并与阴、阳离子型聚丙烯酰胺分散体系进行比较。此外,本文对两性聚丙烯酰胺的应用性能及作用机理进行了分析和探讨。以硫酸铵水溶液为反应介质,可以获得稳定性良好、特性粘数较高的两性聚合物分散体系。随着硫酸铵浓度增加、pH值的增加或引发温度的提高,聚合物特性粘数先增大,然后降低。随着分散剂浓度的降低、单体浓度的增加、引发剂用量的降低和离子度的增加,聚合物特性粘数逐渐升高。同时分散体系的表观粘度和分散体粒径也受各因素的影响较大。最佳反应条件为:硫酸铵浓度28～33%、分散剂用量为0.46g·g^-1、PDMC分子量为1.33-2.90×10⁶、单体浓度10%、引发剂用量400mg·Kg^-1、氯化钠浓度1%、pH值为5-6和温度50-60℃。核磁共振氢谱和元素分析数据表明,所合成的聚合物中各单体的比例与原料比例相近。一点法中计算的两性聚合物的特性粘数和分子量的公式分别为:采用种子分散聚合工艺,反应过程的Weissenberg效应减弱,易于控制,可获得高聚合物含量的分散体系。当分散体系中含有单体时,这些单体可通过粒子的溶剂通道进入粒子内部,使粒径增加,分散体系的粘度上升。硫酸铵浓度对分散体系有很大影响,主要是由于聚合物的溶解性与硫酸铵的浓度密切相关。由于所用分散剂分子中离子基团性质的不同,阴离子型聚合物体系的溶胀程度比阳离子型和两性聚合物体系低。两性聚合物体系与离子型体系的溶胀性也有区别,主要是由于聚合物分子链上带电量不同,造成粒子总体的带电量不同。采用同浓度的盐溶液稀释两性聚丙烯酰胺分散体系,在偏高或偏低的聚合物浓度下,样品体系为剪切变稀型流体;而分散体系被稀释至溶胀浓度时,体系呈现剪切稠化的现象。20%硫酸铵溶液稀释两性聚丙烯酰胺分散体系,体系的粘度先是迅速增加,然后逐渐降低。在被20%的硫酸铵溶液稀释时,由于硫酸铵与聚合物分子的作用不同,两性聚丙烯酰胺分散体系表现出的溶胀性与阳离子型聚丙烯酰胺体系有明显的不同。两性聚丙烯酰胺用作污水絮凝剂或污泥脱水剂时效果良好,产品性能比离子型聚丙烯酰胺高。更多还原

【Abstract】 Functional polyacrylamide （PAM） is one of the hot areas of materials in recently year. Amphoteric polyacrylamide （AmPAM） is a typical polyampholyte with their specific performance. Aqueous dispersion polymerization is the latest technology in the area of soluble polymer. The reaction carried out under mild conditions, while avoiding secondary pollution of organic solvents.In this paper, AmPAM with both anion and cation groups was prepared by dispersion polymerization, with acrylamide （AM） as the main raw material, acrylic acid （AA） as the anionic monomer, methacryloyl ethyl trimethyl ammonium chloride （DMC） as the cationic monomer, ammonium sulfate as the phase separation agent, DMC homopolymer （PDMC） as the dispersion stabilizer and 2,2’-azo-bis（2-methylpropion- amide） dihydrochloride （V-50） as the initiator. Effects of several factors were studied on dispersion polymerization, such as ammonium sulfate concentration, stabilizer concentration and molecular weight, monomer concentration and type, initiator concentration, NaCl concentration, ionic degree, pH value and temperature. Polymer structure was confirmed by NMR 1H spectrum and elemental analysis. Seeded dispersion polymerization was introduced to prepare dispersion with high polymer concentration. The equations of intrinsic viscosity and molecular weight were put forward by tests of several samples. Swelling properties of AmPAM dispersion were investigated by HAAKE rheometer and RheolabQC viscosity, comparing with cationic and anionic polyacrylamide dispersion. In addition, the application performance and effect mechanism of amphoteric polyacrylamide had been analyzed.With （N_H4）₂SO₄ aqueous solution as reaction medium, polymer dispersion with good stability and higher intrinsic viscosity can be prepared. Intrinsic viscosity of polymer would increase first and decrease with increasing of （NH4）2SO4 concentration, pH and temperature. It would increase with increasing of monomer concentration and ionic degree and decreasing of PDMC and V-50 dosage. Particle size and apparent viscosity of AmPAM dispersion would change with variety of all factors. The optical conditions are as follows: （NH₄）₂SO₄ concentration 28-33%, PDMC dosage 400mg·Kg^-1, molecular weight of PDMC 1.33-2.90×10⁶, monomer concentration 10%, V-50 dosage 400mg·Kg^-1, NaCl concentration 1%, pH 5-6 and the temperature 50-60With seeded dispersion polymerization, Weissenberg effect was weakened and the process was easy to control. Meanwhile, the dispersion of higher polymer concentration could be prepared.When there were some monomers in the continuous phase, these monomers could penetrate into the particle through the solvent channel. The particle would become bigger and apparent viscosity of dispersion would increase, too. （NH₄）₂SO₄ concentration had a great influence on the dispersion because the solubility of polymers was closely related with （NH₄）₂SO₄ concentration. Due to the properties’differences of ionic group in stabilizer molecule, swelling degree of anionic polymer dispersion was lower than that of cationic and amphoteric polymer dispersion. Due the difference of charge content in polymer molecule, swelling property of AmPAM dispersion was different from cationic and anionic polymer dispersion.If AmPAM dispersion was diluted by （NH₄）₂SO₄ solution with the concentration equal to original dispersion, the samples were the shear-thinning fluids when the polymer concentration was very high or low. Or, the samples were the shear- thickening fluids. If AmPAM dispersion was diluted by 20% （NH₄）₂SO₄ solution, apparent viscosity of these samples increased fast firstly, and then decreased. As the different role of （NH₄）₂SO₄ on macromolecules, swelling performance of AmPAM dispersion was different from that of cationic polyacrylamide dispersion.The application performance of AmPAM was good when it was used as flocculant and dewatering agent. It was better than ionic polyacrylamide.更多还原