【作者】 王丽；

【导师】 乐园；

【作者基本信息】 北京化工大学 ， 化学工程与技术， 2021， 硕士

【摘要】 聚丙烯酰胺(Polyacrylamide,PAM)聚合物是由丙烯酰胺(Acrylamide,AM)单体均聚或与其它具有功能性的结构单元共聚所合成的一类聚合物,在石油、水处理、造纸、医药等各个领域都具有广泛应用。目前,PAM生产所面临的技术性问题主要包括生产环节投资大、制造工艺落后、产品质量相对偏低等方面,许多高品质PAM产品不得不依赖进口来解决。因此,开发一种高效的聚合反应器仍然被认为是研制和生产出高品质PAM的关键任务。本文将超重力技术与自由基聚合机理相结合,在超重力旋转填充床(Rotating Packed Bed,RPB)反应器中合成了不同种类的聚丙烯酰胺,以分子量为指标进行了工艺优化,并对聚合物产品的结构进行了表征。主要包含以下研究内容:(1)采用RPB反相乳液聚合法,以环己烷为油相,司盘80、吐温20为复配乳化剂,将丙烯酰胺单体溶于去离子水中形成水相,过硫酸铵作单一引发剂,在RPB反应器中合成不同分子量的PAM。主要探究了超重力水平、反应温度、AM单体浓度、引发剂浓度、油水比对PAM分子量及其分布的影响规律,优化了工艺条件。采用红外光谱、核磁氢谱、高效液相色谱等手段对聚合产物的结构、纯度和残留单体含量进行了表征测定。在RPB中可合成出粘均分子量为163万的聚丙烯酰胺,与搅拌釜反应器(Stirred Reactor,STR)相比,RPB制备的聚合产物分子量分布较窄、纯度由92.57%提高至98.66%,产品残余单体含量由0.0073%降至0.0028%,反应时间由8.5 h缩短至40 min,生产效率和产品品质大幅提高。(2)为了进一步提高聚丙烯酰胺分子量,改善聚合反应体系的稳定性,采用RPB反相微乳液聚合法,以性质更为稳定的异构烷烃Isopar-M为油相,司盘80、吐温80作复配乳化剂,将丙烯酰胺单体溶于水溶液中形成水相,将单一引发剂更换为效率更高的氧化还原引发体系作为引发剂,在RPB反应器中继续合成PAM。以粘度法表征PAM的粘均分子量,考察了超重力水平、反应温度、AM单体浓度、引发剂浓度、油水比对PAM分子量的影响规律,对工艺条件进行了优化。采用RPB反相微乳液聚合法在最优工艺条件下合成出的PAM粘均分子量可达329万,产率达84%。与STR生产过程相比较,反应时间由8.5 h缩短至2 h,生产效率得到了提高。(3)采用RPB水溶液聚合法,以氧化还原引发体系作引发剂,海藻酸钠为接枝共聚单体进行RPB反应器内的接枝共聚合反应,合成了不同品质的聚(丙烯酰胺-海藻酸钠)共聚物。重点考察了包括超重力水平、反应温度、丙烯酰胺浓度、引发剂浓度在内的工艺参数对共聚物粘均分子量的影响规律。采用红外光谱、扫描电镜对共聚物进行了结构表征及形貌观察。在最优工艺条件可合成分子量294万、产率达90.19%的聚(丙烯酰胺-海藻酸钠)。与传统搅拌反应器的共聚合反应相比较,反应时间由9 h缩短至3 h。对RPB和STR反应器中最优工艺条件所合成的共聚物进行了絮凝性能的探究,RPB产物的絮凝效果更好。更多还原

【Abstract】 Polyacrylamide(PAM)is a kind of polymer that is made of Acrylamide(AM)monomer homopolymerization or copolymerization with other functional monomers.It has been widely used in petroleum,water treatment,paper making,medicine and other fields.At present,the technical problems encountered in PAM production include large investment in the production process,backward production technology and low product quality.In this paper,polyacrylamide with different qualities was synthesized in a Rotating Packed Bed(RPB)reactor using the combination of high-gravity technology and free radical polymerization mechanism.The process optimization was carried out with its molecular weight as the optimization index,and the structure of the polymer products was characterized.The main research contents are as follows:(1)PAM with different molecular weights were synthesized in RPB reactor by RPB inversed emulsion polymerization,using cyclohexane as oil phase,span-80 and tween-20 as complex emulsifiers,acrylamide monomer aqueous solution as water phase and ammonium persulfate as initiator.The effects of high-gravity level,temperature,AM monomer concentration,initiator concentration,the oil-water ratio on PAM molecular weight and its distribution were studied.The chemical structure,purity,and AM residues of the polymeric products were characterized by IR,1H NMR,and HPLC.PAM with viscosity average molecular weight of 1.63 million can be synthesized in RPB.Compared with the stirred reactor(STR),the molecular weight distribution of the product prepared by RPB is narrower,the purity was increased from 92.57%to 98.66%,the residual monomer content was decreased from 0.0073%to 0.0028%,and the reaction time was shortened from 8.5 h to 40 min.The production efficiency and product quality were greatly improved.(2)In order to further improve the molecular weight of PAM and improve the stability of the polymerization system,PAM with different molecular weight were continued to be synthesized in RPB reactor by RPB inversed microemulsion polymerization.Using more stable isopar-M as oil phase,span80 and tween-80 as complex emulsifiers,the AM monomer aqueous solution as water phase and replacing the single initiator with a more efficient REDOX initiator system composed of ammonium persulfate and sodium bisulfite as the initiator.The viscosity average molecular weight of PAM was characterized by the viscosity method and the effects of high-gravity level,temperature,AM monomer concentration,initiator concentration and oil-water ratio on the molecular weight of PAM were studied.Under the optimal condition,the viscosity average molecular weight of PAM can reach 3.29 million,the yield is 84%.Compared with the STR process,the reaction time was shortened from 8.5 h to 2 h,and the production efficiency was improved.(3)Poly(acrylamide-sodium alginate)copolymers with different qualities were synthesized by graft copolymerization in RPB reactor by RPB aqueous solution polymerization,using REDOX initiator system composed of ammonium persulfate and sodium bisulfite as the initiator and sodium alginate as graft copolymer.The effects of high-gravity level,reaction temperature,acrylamide concentration and initiator concentration on the viscosity average molecular weight of copolymer were researched.The structure and morphology of the copolymer were characterized by IR and SEM.Under the optimal condition,the viscosity average molecular weight of P(AM-SAG)can reach 2.94 million and the yield is 90.19%.Compared with the STR process,the reaction time is shortened from 9 h to 3 h.The flocculation performance of the copolymer synthesized under the optimal process conditions in RPB and STR reactors was studied,and the flocculation effect of the RPB product was better.更多还原