沉淀聚合法制备聚酰亚胺微球
发布时间：2018-11-01 11:12
【摘要】： 聚酰亚胺微球同时具有聚酰亚胺的优异性能(热稳定性、耐溶剂、耐磨性等)和高分子微球在尺寸和结构上的优势,将在催化载体、分离纯化、离子交换等领域有着广阔的应用前景。目前,聚酰亚胺微球的实验研究主要包括:聚酰亚胺实体微球、聚酰亚胺/无机粒子纳米复合微球、聚酰亚胺多孔微球、聚酰亚胺中空微球;制备的方法主要是悬浮聚合法、分散聚合法、再沉淀法等。但是这些制备方法存在过程繁琐、粒子粘结、粒径难控、使用大量的稳定剂等问题。 采用沉淀聚合法制备聚酰亚胺微球,具有过程简单、且不需添加如何稳定剂等特性。在沉淀聚合法制备聚酰亚胺微球过程中,实验考查了几个方面:①沉淀聚合法制备聚酰胺酸微球的影响因素;②聚酰胺酸亚胺化制备聚酰亚胺微球的工艺条件优化;③聚酰亚胺微球的热性能研究。研究表明: (1)沉淀聚合法制备聚酰胺酸微球 分别以四种不良溶剂(甲醇、乙醇、四氢呋喃、丁酮)作为反应体系,制备出四种聚酰胺酸微球。结果显示,以丁酮为溶剂时得到的PAA粒子具有最好的球形形貌;且粒径分布较窄,平均粒径为8.8μm。 丁酮(MEK)与N-甲基吡咯烷酮(NMP)混合溶剂为反应体系(MEK与NMP的体积比20:1、18:1、15:1、13:1、10:1、8:1)时,制备出的聚酰胺酸微球。结果显示当MEK与NMP的体积比为8:1时,粒子具有最好的球型形貌;且为粒径最大,平均粒径为16.5μm。 (2)聚酰胺酸亚胺化制备聚酰亚胺微球的工艺条件优化 采用两种不同的加热形式将聚酰胺酸微球亚胺化,即等温度梯度加热(由室温梯度加热到350℃,从100℃开始停30min,后每升温50℃停留30min)和等时间间隔加热(由室温直接加热到350℃,每隔15min取一次样,总共去5次样),最后得到PI微球。结果显示由等温度梯度加热得到的PI微球形貌、粒径分布、反应程度均优于等时间间隔加热得到的PI微球;等温度梯度加热得到的PI微球的平均粒径为8.8μm,粒径分布较窄。 (3)聚酰亚胺微球的热性能 本文尝试对聚酰亚胺微球的热性能为做了初步的研究,利用凝胶渗透色谱(GPC)分析了三个分子量不同的PI微球,再以DSC对其进行分析。结果表明数均分子量大的聚酰亚胺(abc)微球,其玻璃化温度(Tg)也较高(abc)。
[Abstract]:Polyimide microspheres have both excellent properties of polyimide (thermal stability, solvent resistance, wear resistance, etc.) and advantages in size and structure of polymer microspheres. Ion exchange and other fields have broad application prospects. At present, the experimental research of polyimide microspheres mainly includes: polyimide solid microspheres, polyimide / inorganic particles nanocomposite microspheres, polyimide porous microspheres, polyimide hollow microspheres; The main preparation methods are suspension polymerization, dispersion polymerization, reprecipitation and so on. However, there are some problems in these preparation methods, such as cumbersome process, particle bonding, particle size control, and the use of a large number of stabilizers. The preparation of polyimide microspheres by precipitation polymerization has the advantages of simple process and no need to add stabilizers. In the process of preparing polyimide microspheres by precipitation polymerization, the following aspects were investigated: (1) the factors affecting the preparation of polyamide acid microspheres by precipitation polymerization, (2) the optimization of the process conditions for the preparation of polyimide microspheres by polyamide-imidization; Thermal properties of polyimide microspheres were studied. The results showed that: (1) four polyamide acid microspheres were prepared by precipitation polymerization with four kinds of bad solvents (methanol, ethanol, tetrahydrofuran, butanone) as reaction systems. The results showed that the PAA particles with butanone as solvent had the best spherical morphology, and the particle size distribution was narrow, and the average particle size was 8.8 渭 m. Polyamide acid microspheres were prepared in the mixed solvent of butanone (MEK) and N-methylpyrrolidone (NMP) (volume ratio of MEK to NMP was 20: 1 18: 1 15: 1 13: 1 10: 1 1: 8: 1). The results show that when the volume ratio of MEK to NMP is 8:1, the particle has the best spherical morphology, and the particle size is the largest, the average particle size is 16.5 渭 m. (2) the process conditions for the preparation of polyimide microspheres by imidization of polyamide acid were optimized. Two different heating methods were used to prepare polyimide microspheres, I. e., equal temperature gradient heating (from room temperature gradient to 350 鈩，
本文编号：2303752
[Abstract]:Polyimide microspheres have both excellent properties of polyimide (thermal stability, solvent resistance, wear resistance, etc.) and advantages in size and structure of polymer microspheres. Ion exchange and other fields have broad application prospects. At present, the experimental research of polyimide microspheres mainly includes: polyimide solid microspheres, polyimide / inorganic particles nanocomposite microspheres, polyimide porous microspheres, polyimide hollow microspheres; The main preparation methods are suspension polymerization, dispersion polymerization, reprecipitation and so on. However, there are some problems in these preparation methods, such as cumbersome process, particle bonding, particle size control, and the use of a large number of stabilizers. The preparation of polyimide microspheres by precipitation polymerization has the advantages of simple process and no need to add stabilizers. In the process of preparing polyimide microspheres by precipitation polymerization, the following aspects were investigated: (1) the factors affecting the preparation of polyamide acid microspheres by precipitation polymerization, (2) the optimization of the process conditions for the preparation of polyimide microspheres by polyamide-imidization; Thermal properties of polyimide microspheres were studied. The results showed that: (1) four polyamide acid microspheres were prepared by precipitation polymerization with four kinds of bad solvents (methanol, ethanol, tetrahydrofuran, butanone) as reaction systems. The results showed that the PAA particles with butanone as solvent had the best spherical morphology, and the particle size distribution was narrow, and the average particle size was 8.8 渭 m. Polyamide acid microspheres were prepared in the mixed solvent of butanone (MEK) and N-methylpyrrolidone (NMP) (volume ratio of MEK to NMP was 20: 1 18: 1 15: 1 13: 1 10: 1 1: 8: 1). The results show that when the volume ratio of MEK to NMP is 8:1, the particle has the best spherical morphology, and the particle size is the largest, the average particle size is 16.5 渭 m. (2) the process conditions for the preparation of polyimide microspheres by imidization of polyamide acid were optimized. Two different heating methods were used to prepare polyimide microspheres, I. e., equal temperature gradient heating (from room temperature gradient to 350 鈩，
本文编号：2303752
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