聚丙烯酰胺的反相乳液聚合及其絮凝沉降性能研究

【作者】 常庆伟；

【导师】 钟宏；

【作者基本信息】 中南大学 ， 化学工程， 2010， 硕士

【摘要】 论文采用反相乳液聚合法制备较高分子量的非离子型和阳离子型聚丙烯酰胺乳液絮凝剂,并通过对非离子型聚丙烯酰胺乳液进行“后水解处理”,制备了阴离子型聚丙烯酰胺乳液产品。反相乳液聚合制备非离子型聚丙烯酰胺的最佳工艺条件为：反应温度为45℃,反应时间为4h,引发剂V-50用量为0.2‰,乳化剂用量为6%,HLB=6,单体浓度为40%,油水比为1.0：1.0,EDTA-2Na用量为0.5‰。聚合工艺条件具有良好的重现性,得到聚合产物相对分子质量高达1100万,通过FT-IR和DSC-TGA对产物结构和热稳定性进行了表征,证明聚合物为AM均聚产物,并且具有良好的热稳定性。以上述乳液产品为水解原料,以NaOH为水解剂,理论水解度为30%,水解温度为60℃,水解时间为2h的条件下,得到实际水解度为24.5%,相对分子质量660万的部分水解聚丙烯酰胺乳液产品。以丙烯酰胺(AM)和甲基丙烯酰氧乙基三甲基氯化铵(DMC)为共聚单体,通过反相乳液聚合制备高分子阳离子共聚物P(DMC-AM)的最佳工艺条件为：引发剂V-50用量为1.4‰、乳化剂用量为6%、EDTA-2Na用量为1.0‰、亲水亲油平衡值为6、单体浓度为40%、单体配比为n(DMC):n(AM)=5:95、油水质量比为1.1:1.0、pH值为5、反应温度为50℃及反应时间为4h,在上述条件下,所得产物的相对分子质量可达580万。通过FT-IR对产物结构进行了表征,证实了制备的聚合物为目标产物。考察了上述乳液絮凝剂对铝土矿正浮选尾矿浆的沉降絮凝性能,结果表明：阴离子型聚丙烯酰胺产品显现出优异的絮凝性能,在用量20g/t时,沉降速度、固液分离及上清液澄清度均取得良好效果。更多还原

【Abstract】 In this paper, non-ionic polyacrylamide and cationic polyacrylamide with high molecular weight were synthesized by the means of Inverse Emulsion Polymerization, anionic polyacrylamide emulsion was synthesized by the means of hydrolization of non-ionic polyacrylamide with alkali added in later process.The optimum conditions of preparing non-ionic polyacrylamide using Inverse Emulsion Polymerization was that:reaction temperature 45℃, reaction time 4h, amount of initiator 0.2‰, amount of emulsifier 6%, HLB=6, mass fraction of monomer 40%, the mass ratio of oil to water 1.0:1.0,EDTA-2Na 1.0‰. Unde this condition, the obtained polymer with high molecular weight 1100×104 showed good reproducibility.The above-mentioned emulsion was hydrolyzed at optimum hydrolysis conditions:the hydrolysis agent NaOH, theoretical degree of hydrolization 30%, temperature 60℃, time two hours. Under this condition, Partially hydrolyzed polyacrylamide latex was obtained with DH 24.5% and molecular weight over 660x 104.Cationic polyacrylamide P(DMC-AM) was synthesized with acrylamide(AM) and methacrylatoethyl trimethyl ammonium chloride(DMC) as co-monomers by Inverse Emulsion Polymerization in this paper,the optimal conditions were as follows:amount of initiator 1.4%o, amount of emulsifier 6%, HLB=6, mass fraction of monomer 40%, EDTA-2Na 1.0‰, the molar ratio of DMC to AM 5:95, the mass ratio of oil to water 1.1:1.0, pH=5, reaction temperature 50℃and reaction time 4h. Under above conditions, the molecular weight of the product was 580×104. Through Fourier transform infrared spectrum (FT-IR) measurement, the product was proved to cationic copolymer P(DMC-AM).The flocculation behavior of bauxite forward flotation tailings aqueous system was investigated by the sedimentation test, the experimental result revealed that the flocculation effect of anionic polyacrylamide flocculant was better than nonionic and cationic polyacrylamide, the sedimentation rate was higher,the liquid-solid separating effect was distinct and the up liquid was clear at the best dosage 20g/t.更多还原