分散聚合及单分散聚合物微球制备技术

分散聚合是一种新的聚合方法 ,反应开始前 ,单体、引发剂和分散剂均溶解在介质中 ,随着反应的进行 ,当聚合物链达到临界值时便会从介质中分离出来 ,并借助于分散剂稳定地悬浮在介质中。分散聚合方法已被应用于许多领域 ,如涂料工业、生物工程、医学、信息产业、化学工业等。介绍了分散聚合及单分散聚合物微球制备技术的进展 ,并对其聚合机理及聚合反应影响因素进行了概述。     

分散聚合法制备单分散聚苯乙烯微球

用分散聚合法,在乙醇/水介质中,以苯乙烯为单体,偶氮二异丁腈为引发剂,聚乙烯吡咯烷酮为分散剂制备了聚苯乙烯(PS)微球。探讨了制备条件对微球形貌、粒径及粒径分布的影响。结果表明,在合适条件下,可以制备粒径在1μm左右,粒径分布在1.04~1.08,表面光滑且互不粘连的单分散PS微球。     

单分散亚微米级聚合物微球的研究进展

本文综述了单分散亚微米级聚合物微球的自由基聚合主要制备方法,包括分散聚合、RAFT分散聚合、乳液聚合和无皂乳液聚合,讨论了溶剂、引发剂、单体、分散剂、乳化剂、搅拌和温度的选择及其对聚合物微球粒径和单分散性的影响以及粒径控制机理.     

大粒径单分散聚合物微球的合成及应用

大粒径单分散聚合物微球是近20年来开发出来的用途很广的球形高分子粒子,它可以用分散聚合、溶胀法、无皂乳液聚合等方法制备。本文对其在国内外的发展溉况进行了评述。     

分散聚合制备单分散聚合微球

分散聚合是近年发展起来的制备大粒径单分散高分子微球的聚合新方法,体现着无法比拟的优越性,可以制备多种带有功能基团的微球,应用广泛。本文介绍了分散聚合的机理特点和影响合成的因素,概述了对单分散微球几种常用的表征方法。     

辐射引发分散聚合反应制备聚合物微球研究进展

介绍了辐射作用原理、辐射引发分散聚合反应技术和机理、及其最新研究进展：重点阐述了超声、紫外光、γ射线、微波辐射在分散聚合中的应用。     

分子印迹和单分散聚合物微球的研究进展

阐述了分子印迹的概念,发展历史,印迹的原理以及分子印迹在分离、催化、传感器等方面的应用。在分子印迹聚合物的传统制备方法和存在的问题中引出分散聚合。简述了传统制备聚合物微球的一些方法特点和分散聚合法的优越性。最后讨论了用分散聚合制备分子印迹聚合物微球可能存在的一些困难。     

大粒径单分散聚合物微球的制备及其在LCD中的应用进展

单分散聚合物微球的制备和应用是近年来人们研究的热点。综述了单分散聚合物微球的制备方法和研究进展,具体介绍了分散聚合和种子聚合。并对其在液晶显示器(Liquid Crystal Display,LCD)中的应用进行了介绍,对其未来的研究方向和应用前景进行了展望。     

单分散聚合物微球的制备及功能化研究进展

综述了单分散聚合物微球常用的制备方法(乳液聚合法、种子聚合法、分散聚合法、沉淀聚合法、悬浮聚合法和膜乳化法等),介绍了单分散聚合物微球的功能化研究进展,包括磁性微球、多孔微球、温度/pH响应微球、阳离子微球以及微球官能团化等等。最后提出了多种聚合方法的相互结合是制备功能性单分散聚合物微球的一大趋势,开发多功能的单分散聚合物微球、实现批量生产是其近期的重点研究方向。     

微米级单分散聚苯乙烯微球的制备

以苯乙烯(St)为单体、偶氮二异丁腈(AIBN)为引发剂、聚乙烯吡咯烷酮(PVP)为分散稳定剂,在乙醇-水反应介质中,采用分散聚合法制备了微米级单分散聚苯乙烯(PS)微球。分别用电镜扫描和激光粒度仪表征了PS微球表面形貌、粒径及粒度分布,探讨了影响PS微球粒径及粒度分布的诸多因素。结果表明,AIBN用量(以单体质量计,下同)大于5.0%或PVP用量(以单体质量计,下同)小于2%时,PS粒子间有聚并现象;当St浓度为10%、AIBN用量为2.5%、PVP用量为5.5%、醇水质量比为90∶10、聚合温度为70℃时,制备的PS微球粒径为1.612μm、粒度分散系数为0.357,微球单分散性及球形度最佳。     

Production of micron-size monodisperse polymer particles by seeded polymerization utilizing dynamic swelling method with cooling process

Monodisperse polystyrene particles (6.6 μm diameter) were produced by seeded polymerization utilizing the dynamic swelling method with cooling process as follows. Monodisperse polystyrene seed particles (1.8 μm diameter) were dispersed in ethanol/water (3/4 w/w) medium containing styrene monomer, benzoyl peroxide as initiator and poly(vinyl alcohol) as stabilizer at 65d?C. By lowering the temperature to ?5d?C at a speed of ?1d?C/min the polystyrene seed particles were swollen from 1.8 to 7.7 μm by the absorption of styrene monomer, keeping the high monodispersity. An appropriate amount of water was then added to the dispersion at ?5d?C to depress the redissolution of styrene from the swollen particles into the medium. By elevating the temperature the seeded polymerization was carried out at 70d?C. The production of submicron-size polystyrene new particles as a by-product was depressed by the addition of NaNO₂ to the medium.     

单分散大粒径交联聚苯乙烯微球的制备及功能化改性的研究进展

单分散的聚合物功能微球具有许多突出优点,如比表面积大、表面反应能力强等。系统地分析和综述了单分散交联聚苯乙烯功能微球的制备方法及应用的最新研究进展,并对该类功能材料的发展前景进行了预测。     

多孔聚合物微球的制备及其在化妆品中的应用进展

简要介绍了单分散多孔聚合物微球的应用,重点综述了多孔聚合物微球用作化妆品活性物载体时所起的控释和缓释作用;讨论了多孔聚合物微球的合成手段,包括悬浮聚合法、分散聚合法和种子溶胀法,种子溶胀法中的动态溶胀法和二步溶胀法更易得到粒径均一的多孔聚合物微球;同时介绍了其成孔机理和性能表征;最后提出了多孔聚合物合成以及在化妆品应用中目前存在的问题、发展方向和应用前景。     

乳液聚合法合成水杨酸分子印迹聚合物微球

以水杨酸为模板分子,乙二醇二甲基丙烯酸酯为交联剂,采用乳液聚合法制备了水杨酸分子印迹聚合物微球（SMIP）,采用紫外差示光谱分析了模板分子与功能单体的相互作用,以荧光分光光度计为检测手段,讨论了不同功能单体、模板分子与功能单体的摩尔比、交联剂用量、洗脱液类型等对SMIP吸附性能的影响,并进一步考察了SMIP的形貌和粒径分布。研究结果表明,以丙烯酰胺为功能单体合成的SMIP表现出较好的吸附性能,印迹因子可达1.61,而且微球呈单分散性,平均粒径约60 nm。     

Formation of monodisperse polyacrylamide particles by radiation‐induced dispersion polymerization. I. Synthesis and polymerization kinetics

Highly monodisperse polyacrylamide (PAM) microparticles were directly prepared by radiation‐induced dispersion polymerization at room temperature in an aqueous alcohol media using poly(N‐vinylpyrrolidone) (PVP) as a steric stabilizer. Monomer conversion was studied dilatometrically and polymer molecular weight was determined viscometrically. The gel effect was found evidently from the polymerization kinetics curves. The influence of the dose rate, monomer concentration, stabilizer content, medium polarity, polymerization temperature on the polymerization rate, and the molecular weight of the polymer was examined. The polymerization rate (Rp) can be represented by Rp ∝ D^0.15[M]^0.86[S]^0.47[A/W]^0.64 and the molecular weight of the polymer can be represented by M_w ∝ D^?0.19 [M]^1.71[S]^0.43[A/W]^0.14 at a definite experimental variation range. The overall activation energy for the rate of polymerization is 10.57 kJ/mol (20–35°C). Based on these experimental results, the polymerization mechanisms were discussed primarily. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2567–2573, 2002     

Formation of monodisperse polyacrylamide particles by dispersion polymerization: particle size and size distribution

Highly monodisperse polyacrylamide microparticles were directly prepared by dispersion polymerization in aqueous alcoholic media initiated by 2,2′‐azobisisobutyronitrile using poly(N‐vinylpyrrolidone) as a steric stabilizer. Monomer conversion was studied dilatometrically and polymer molecular weight was determined viscometrically. The hydrodynamic diameter of polymer particles and its distribution were measured with a dynamic laser light scattering spectrometer. The number of the nuclei produced in the early stage of the polymerization was found to be constant during the remainder of the polymerization. The influences of various polymerization parameters, such as initiator concentration, monomer concentration, stabilizer content, medium polarity, and polymerization temperature on the particle size and size distribution were systematically investigated. Copyright © 2003 Society of Chemical Industry     

The influence of water on size of the monodisperse polystyrene microspheres prepared by dispersion polymerization

Polystyrene microspheres with uniform sizes have a wide range of applications in biomedical engineering. However, detailed and systematic investigations on the influence of water content on alcohol/water systems are relatively scarce. In this study, the impact of trace water content on microsphere size was comprehensively examined, and a systematic exploration of the varying effects of different hydration levels on particle nucleation and growth mechanisms was conducted. When the water content increased from 0.1% to 0.4%, the microsphere diameter rapidly decreases from 3.6 to 2.71 μm. Correspondingly, the molecular weight increased from 29,797 to 69,186. However, within the water content range of 0.5%–14.5%, alterations in water content induced only slight variations in the microsphere diameter. The microsphere size, molecular weight, conversion rate, and reaction rate were compared in two stages. It was observed that the diminishing influence of water on the system was due to the changes in the main polymerization sites. Subsequently, the addition of water content up to 33.5% revealed an exponential decrease in the microsphere size with increasing water content in ethanol. This pattern was also observed in methanol and isopropanol, demonstrating its universality and predictability, making it applicable for precise prediction of microsphere size in different solvents.     

单分散St-PEG200DMA交联共聚微球的合成

以苯乙烯（St）为主单体,PEG200DMA(polyethelyene glycol 200-dimethacrylae)为交联剂,偶氮二异丁腈（AIBN）为引发剂,聚乙烯吡咯烷酮（PVP）为稳定剂,利用一次投料分散聚合的方法合成了交联的St-PEG200DMA共聚微球.实验发现,共聚单体PEG200DMA的投料量对微球的粒径影响不大,但对其形态影响显著.当交联剂的投料量到单体的2.5％时,得到了单分散性好的“花瓣状”微球,这种特异的表面形貌是由交联剂的链段结构决定的.