【摘要】： 聚酰亞胺微球同時(shí)具有聚酰亞胺的優(yōu)異性能(熱穩(wěn)定性、耐溶劑、耐磨性等)和高分子微球在尺寸和結(jié)構(gòu)上的優(yōu)勢,將在催化載體、分離純化、離子交換等領(lǐng)域有著廣闊的應(yīng)用前景。目前,聚酰亞胺微球的實(shí)驗(yàn)研究主要包括:聚酰亞胺實(shí)體微球、聚酰亞胺/無機(jī)粒子納米復(fù)合微球、聚酰亞胺多孔微球、聚酰亞胺中空微球;制備的方法主要是懸浮聚合法、分散聚合法、再沉淀法等。但是這些制備方法存在過程繁瑣、粒子粘結(jié)、粒徑難控、使用大量的穩(wěn)定劑等問題。 采用沉淀聚合法制備聚酰亞胺微球,具有過程簡單、且不需添加如何穩(wěn)定劑等特性。在沉淀聚合法制備聚酰亞胺微球過程中,實(shí)驗(yàn)考查了幾個(gè)方面:①沉淀聚合法制備聚酰胺酸微球的影響因素;②聚酰胺酸亞胺化制備聚酰亞胺微球的工藝條件優(yōu)化;③聚酰亞胺微球的熱性能研究。研究表明: (1)沉淀聚合法制備聚酰胺酸微球 分別以四種不良溶劑(甲醇、乙醇、四氫呋喃、丁酮)作為反應(yīng)體系,制備出四種聚酰胺酸微球。結(jié)果顯示,以丁酮為溶劑時(shí)得到的PAA粒子具有最好的球形形貌;且粒徑分布較窄,平均粒徑為8.8μm。 丁酮(MEK)與N-甲基吡咯烷酮(NMP)混合溶劑為反應(yīng)體系(MEK與NMP的體積比20:1、18:1、15:1、13:1、10:1、8:1)時(shí),制備出的聚酰胺酸微球。結(jié)果顯示當(dāng)MEK與NMP的體積比為8:1時(shí),粒子具有最好的球型形貌;且為粒徑最大,平均粒徑為16.5μm。 (2)聚酰胺酸亞胺化制備聚酰亞胺微球的工藝條件優(yōu)化 采用兩種不同的加熱形式將聚酰胺酸微球亞胺化,即等溫度梯度加熱(由室溫梯度加熱到350℃,從100℃開始停30min,后每升溫50℃停留30min)和等時(shí)間間隔加熱(由室溫直接加熱到350℃,每隔15min取一次樣,總共去5次樣),最后得到PI微球。結(jié)果顯示由等溫度梯度加熱得到的PI微球形貌、粒徑分布、反應(yīng)程度均優(yōu)于等時(shí)間間隔加熱得到的PI微球;等溫度梯度加熱得到的PI微球的平均粒徑為8.8μm,粒徑分布較窄。 (3)聚酰亞胺微球的熱性能 本文嘗試對聚酰亞胺微球的熱性能為做了初步的研究,利用凝膠滲透色譜(GPC)分析了三個(gè)分子量不同的PI微球,再以DSC對其進(jìn)行分析。結(jié)果表明數(shù)均分子量大的聚酰亞胺(abc)微球,其玻璃化溫度(Tg)也較高(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，

本文編號(hào)：2303752