两步种子溶胀聚合研究进展*

由两步种子溶胀聚合法制备的聚合物微球尺寸均一可控,制备的多孔微球孔径、孔分布可控,被广泛应用于色谱柱填料、离子交换树脂、生物分离和催化剂载体等领域。本文介绍了两步种子溶胀聚合的聚合工艺;阐述了两步种子溶胀聚合的溶胀机理以及用该法制备多孔微球的致孔机理;进一步分析了影响两步种子溶胀聚合的各种因素：包括聚合过程的控制以及聚合配方的控制因素等;简要综述了通过该方法所制备的多孔聚合物微球,并对两步种子溶胀聚合方法今后的发展进行了展望。     

光致变色多孔聚苯乙烯功能微球的制备和性能

以甲苯/庚烷为致孔剂,利用分散聚合技术制备了多孔交联聚苯乙烯微球.研究了聚合单体、引发剂、稳定剂、交联剂等对微球平均粒径的影响,并初步评价了其在常温常压下吸附光致变色材料后的光致变色性能.结果表明,在最佳条件下制得的多孔聚合物微球平均粒径为1 μm;吸附光致变色材料后,其在紫外或日光照射下具有快速可逆的光致变色功能.利...     

高分子多孔微球产品的制备及其在类病毒颗粒分离纯化中的应用

高分子多孔微球在医药领域的分离纯化中应用广泛,是重要的化工产品。高分子多孔微球的形成是一个复杂的过程,利用聚合物与有机溶剂致孔剂的相分离,可得到小于100 nm孔径的多孔微球;而水和疏水性聚合物之间相分离程度远大于有机溶剂与聚合物间的相分离程度,因此可获得大于100 nm孔径的多孔微球。针对不同应用领域选择不同的方法,设计并制备出合理的微球结构,对多孔微球的实际应用十分关键。本综述介绍了纳孔、介孔、大孔微球产品的制备方法悬浮聚合和种子聚合法,重点介绍本课题组制备超大孔微球的方法--反胶团溶胀法和W/O/W复乳法,上述两种方法解决了常规方法难以制备大孔径微球产品的问题,拓展了多孔微球在类病毒颗粒等大尺寸蛋白分离纯化领域的应用。在此基础上,以HB-VLPs为模型对比了不同孔径微球对类病毒颗粒吸附量、回收率、结构、以及纯化效果的差异,揭示超大孔微球产品在类病毒颗粒分离纯化中的优势。     

季戊四醇三丙烯酸酯-丙烯酸丁酯共聚微球的合成及孔结构特性研究

以季戊四醇三丙烯酸酯、丙烯酸丁酯为共聚单体,乙酸丁酯为致孔剂,用悬浮聚合法合成了-系列不同表面结构的共聚微球.使用扫描电镜、BET氮气吸附,傅立叶红外光谱等分析手段,对微球进行了结构测定,并研究了单体与致孔剂比例、两种单体比例及不同致孔剂对于聚合物孔结构的影响.经过合成条件的筛选,得到了平均孔径为100nm左右的球形聚合物.     

二氧化钛接枝聚(苯乙烯-二乙烯苯)/马来酸酐多孔纳米复合微球的制备及表征 二氧化钛接枝聚(苯乙烯-二乙烯苯)/马来酸酐 多孔纳米复合微球的制备及表征

中孔聚合物微球, 由于具有大的比表面积、小的孔径和孔容, 并有与外界环境介质相通的多孔孔道等特点而被应用于化妆品活性物和药物的缓释载体, 以提高药物及化妆品活性物的安全性和使用效率. 在早期的工作中, 我们报道了聚苯乙烯-二乙烯苯[P(St- DVB)]多孔聚合物微球的制备及其在化妆品活性物缓释中的应用[4]. [P(St-DVB)]多孔聚合物微球用于化妆品活性物的负载取得了较好的缓释效果, 但是此种多孔聚合物微球在负载如Pasorl-1789类易光解的活性组分时, 由于聚合物本身的透明性, 当在紫外线等强光照射下, 易光解的活性物就会发生分解, 最终导致失去活性作用, 因此纯的聚合物微球对易光解的活性物起不到良好的保护和缓释. 纳米二氧化钛由于具有良好的紫外吸收和折射能力及无毒等优点而广泛地应用于化妆品的物理防晒剂. 因此, 将纳米二氧化钛均匀地覆盖在多孔聚合物微球的表面可以在聚合物微球表面形成一道阻挡紫外线的屏障, 有效防止负载于多孔聚合微球内部的活性物的分解. 本文通过开环反应方法制备了二氧化钛接枝聚(苯乙烯-二乙烯苯)/马来酸酐中孔复合微球. 首先用氨基基团对纳米二氧化钛粒子表面进行修饰, 一方面防止其团聚, 另一方面使纳米粒子具有与聚合物微球产生共价键合的基团. 然后对多孔聚合物粒子表面进行马来酸酐修饰, 使其在保持原有的多孔形貌的基础上产生可与纳米粒子表面氨基开环反应的马来酸酐基团. 制得的多孔纳米复合微球经红外光谱、扫描电镜、透射电镜、X光衍射能谱及紫外分光光度计等表征, 结果表明, 纳米复合微球表面均匀地覆盖了纳米二氧化钛粒子, 复合粒子比纯聚合物粒子和未经修饰的二氧化钛粒子具有更好的紫外吸收效果. 将制得的复合微球用于对活性物Parsol 1789 (一种化妆品活性组分, 见光易氧化)的负载和缓释结果表明, 纳米复合多孔微球对负载于多孔网络中的活性物具有屏蔽紫外防止氧化和缓释作用.     

二氧化钛接枝聚(苯乙烯-二乙烯苯)/马来酸酐多孔纳米复合微球的制备及表征

中孔聚合物微球,由于具有大的比表面积、小的孔径和孔容,并有与外界环境介质相通的多孔孔道等特点而被应用于化妆品活性物和药物的缓释载体,以提高药物及化妆品活性物的安全性和使用效率.在早期的工作中,我们报道了聚苯乙烯-二乙烯苯[P(St-DVB)]多孔聚合物微球的制备及其在化妆品活性物缓释中的应用[4].[P(St-DVB)]多孔聚合物微球用于化妆品活性物的负载取得了较好的缓释效果,但是此种多孔聚合物微球在负载如Pasorl-1789类易光解的活性组分时,由于聚合物本身的透明性,当在紫外线等强光照射下,易光解的活性物就会发生分解,最终导致失去活性作用,因此纯的聚合物微球对易光解的活性物起不到良好的保护和缓释.纳米二氧化钛由于具有良好的紫外吸收和折射能力及无毒等优点而广泛地应用于化妆品的物理防晒剂.因此,将纳米二氧化钛均匀地覆盖在多孔聚合物微球的表面可以在聚合物微球表面形成一道阻挡紫外线的屏障,有效防止负载于多孔聚合微球内部的活性物的分解.本文通过开环反应方法制备了二氧化钛接枝聚(苯乙烯-二乙烯苯)/马来酸酐中孔复合微球.首先用氨基基团对纳米二氧化钛粒子表面进行修饰,一方面防止其团聚,另一方面使纳米粒子具有与聚合物微球产生共价键合的基团.然后对多孔聚合物粒子表面进行马来酸酐修饰,使其在保持原有的多孔形貌的基础上产生可与纳米粒子表面氨基开环反应的马来酸酐基团.制得的多孔纳米复合微球经红外光谱、扫描电镜、透射电镜、X光衍射能谱及紫外分光光度计等表征,结果表明,纳米复合微球表面均匀地覆盖了纳米二氧化钛粒子,复合粒子比纯聚合物粒子和未经修饰的二氧化钛粒子具有更好的紫外吸收效果.将制得的复合微球用于对活性物Parsol1789(一种化妆品活性组分,见光易氧化)的负载和缓释结果表明,纳米复合多孔微球对负载于多孔网络中的活性物具有屏蔽紫外防止氧化和缓释作用.     

反相非水乳液制备多孔聚酰亚胺微球

在Span85/N,N-二甲基甲酰胺/液体石蜡稳定反相非水乳液体系中,以均苯四甲酸酐和4,4’-二氨基二苯醚为单体,选用甲醇、二硫化碳作为致孔剂,制备多孔聚酰亚胺(PI)微球.通过SEM、量子化学模拟、粒径测试等手段考察致孔剂种类、致孔剂用量、吡啶/酸酐滴加速度及反应温度和单体浓度对致孔的影响.结果表明,选用二硫化碳、甲醇为致孔剂时所制得的微球形貌良好,但CS2为致孔剂时,所得到的微球孔道很少;而甲醇为致孔剂时,则得到了孔道明显的多孔PI微球.致孔的最佳条件为反应温度20℃,单体浓度10%,吡啶/酸酐滴加速度0.5 s/滴时,才可得到的形貌良好、分布均一的多孔PI微球.而且随着甲醇/液体石蜡的体积比增加,多孔PI微球比表面积也随着增大,最大可达29.38 m2/g.所得产物粒径分布在20~30μm之间,热稳定性良好,其起始热分解温度为517℃.     

二氧化钛接枝聚（苯乙烯-二乙烯苯）/马来酸酐多孔纳米复合微球的制备及表征（摘要）

中孔聚合物微球,由于具有大的比表面积、小的孔径和孔容,并有与外界环境介质相通的多孔孔道等特点而被应用于化妆品活性物和药物的缓释载体,以提高药物及化妆品活性物的安全性和使用效率.在早期的工作中,我们报道了聚苯乙烯-二乙烯苯[P（St-DVB）]多孔聚合物微球的制备及其在化妆品活性物缓释中的应用[4].[P（St-DVB）]多孔聚合物微球用于化妆品活性物的负载取得了较好的缓释效果,但是此种多孔聚合物微球在负载如Pasorl-1789类易光解的活性组分时,由于聚合物本身的透明性,当在紫外线等强光照射下,     

贯通多孔聚合物微球的制备及其应用

采用高内水相双重乳液模板法制备贯通多孔聚合物微球,并将其应用于催化剂负载和Cu2+吸附.首先,通过增加水相,使单一小分子表面活性剂12-丙烯酰氧-9-油酸(AOA)稳定的反相高内相乳液(W/O HIPEs)发生相转变,一步制备出高内水相双重乳液;然后以此为模板,采用辐射法和引发剂引发聚合两种方式制备聚(苯乙烯-二甲基丙烯酸乙二醇酯)微球.通过扫描电镜观察发现,采用辐射法聚合能够得到贯通多孔的聚合物微球,而化学法聚合只能得到中空的封闭微球.将贯通多孔微球水解使其羧基化,用于铜离子的吸附.结果表明水解后多孔微球对Cu2+的吸附量随p H值的增加先增后减,在p H=5时达到最高值175 mg/g(2.75 mmol/g).此外,利用原位生成的方式,在贯通多孔微球上负载Pd纳米粒子,并将其用于催化肉桂醛加氢反应.结果表明水解多孔微球比未水解多孔微球具有更高的催化效率;热重分析和透射电子显微镜观察显示,水解多孔微球比未水解多孔微球能够负载更多的Pd纳米粒子,且纳米粒子分散更均匀.     

基于聚合物的轻质微球的制备和应用

具有密度低、比表面积高、稳定性好、表面渗透能力强和负载能力高等特点的轻质微球得到了国内外研究者的关注。本文综述了基于聚合物轻质微球的最新研究进展,详细介绍了中空微球和多孔微球的制备方法,主要包括种子溶胀法、模板法、悬浮聚合法、层层自组装法、表面分子印迹法和液-液相分离法,阐述了轻质微球在生化医学、涂料、废水处理、生物传感器及电子信息领域等方面的应用进展,指出了有效控制中空微球内腔结构,调控多孔微球的孔结构是未来的研究方向。     

超临界CO2在高分子合成与制备中的应用

介绍超临界二氧化碳流体作为介质在高分子合成与制备中的研究进展。文中表明，可在超临界二氧化碳中实施氟代单体的自由基溶液聚合、甲基丙烯酸甲酯的分散聚合、丙烯酸的沉淀聚合、丙烯酰胺的反相乳液聚合以及异丁基乙烯基醚的阳离子聚合等多种聚合反应，可用超临界二氧化碳溶胀聚合法制备梯度共混物。此外，超临界二氧化碳还可用于聚合物分级和聚合物微孔、微纤与微球材料的制备等，显示出超临界二氧化碳是一种对环境无污染且价廉的     

Control of heterogeneous structure of porous polymer microspheres prepared from polymerization system and preformed polymer system

The studies on control of heterogeneous structure of porous polymer microspheres prepared for suspension polymerization system and preformed polymer system in author’s research group were reviewed. Firstly, the phase-separation behavior in O/W suspension polymerization system for preparation of porous poly(divinylbenzene) microspheres was quantitatively studied by combining transmittance and gelation point measurement, from which the morphology can be manipulated. The same method can be employed to study the pore size control in W/O hydrophilic polymerization system. Because the simple porous microsphere could not satisfy new applications, we developed new methods to prepare gigaporous microsphere, which possessed much larger pores than those obtained by general diluents, for chromatographic separation media, as well as hollow-porous microsphere for construction of cell-like microreactor. Furthermore, in order to overcome the difficulty of heterogeneous structure control for preformed polymer system, we developed special methods to obtain porous, hollow-porous, and hollow chitosan microspheres. Finally, some application results by utilizing special morphologies were introduced.     

Pore structural studies of monodisperse porous polymer particles

Monodisperse polystyrene latex particles with molecular weight on the order of 10⁶ were used as inert diluents for the preparation of monodisperse porous styrene-divinylbenzene copolymer particles via seeded emulsion polymerization techniques. Mercury porosimetry and nitrogen adsorption-desorption isotherms were used to assess pore structure and pore size distribution. Pore size distribution was very sensitive to the molecular weight of the polystyrene latex particles used as inert diluent. Qualitative evidence from the techniques used indicated that the monodisperse porous polymer particles were macroporous (average pore diameter > 500 Å) in nature. As the molecular weight of the linear polymer decreased, the porous structure of the polymer particles ranged in complexity across the spectrum of macro/mesopore structures. Scanning electron microscope results indicated the existence of voids between the microspheres and their agglomerates within the porous polymer particle, and nitrogen adsorption isotherms confirmed that the pores were due to interstices between these crosslinked microspheres and agglomerates.     

超临界二氧化碳中的高分子合成

近年来,超临界二氧化碳（sc-CO2）在聚合反应中的应用受到了越来越多的关注。本文主要综述了以sc-CO2为反应介质的自由基聚合、阳离子聚合、过渡金属催化聚合、热致开环聚合、溶胶-凝胶聚合以及氧化耦合聚合的研究概况。一系列研究结果表明sc-CO2是非常有前途的反应溶剂,在高分子合成领域将会有更加广阔的应用前景。     

超临界二氧化碳对不同聚合方法制备的交联聚合物微球的塑化研究

采用分散聚合和无皂乳液聚合的方法,我们制备了粒径不同的交联聚合物微球。通过改变超临界二氧化碳的压力、处理微球的时间以及实验的温度,我们可以实现对这些微球塑化程度的调节。研究发现,随着超临界二氧化碳压力的升高,其对聚合物微球的塑化能力呈现出先增强后降低的趋势。文中我们对这种现象出现的机理也进行了相应的讨论。随着体系温度的升高或者延长处理微球的时间,超临界二氧化碳对两种微球的塑化能力都呈增强趋势。由于乳液聚合得到的聚合物的分子量通常会比分散聚合得到的聚合物的分子量大,因此在相同的条件下超临界二氧化碳对分散聚合法制备的微球塑化能力更强。     

Monodisperse porous polymer particles: Formation of the porous structure

Monodisperse porous styrene-divinylbenzene copolymer particles were prepared via seeded emulsion polymerization using a mixture of linear polymer (polystyrene seed) and non-solvent as inert diluent. Experimental evidence was presented to describe the mechanism of formation of porous polymer particles during the copolymerization and solvent extraction stages, in which porosity was a consequence of phase separation in the presence of diluents. Pore structure formation was investigated by changes in copolymerization kinetics, gel content, crosslinking density, particle morphology, surface area, pore volume, and pore size distribution. The process of copolymerization was presented, based on the concepts of production, agglomeration, and fixation of the interior gel microspheres of polymer particles. A portion of linear polymer used as diluent was found to participate in the network structure while the porous matrix was built-up. The influence of the removal of the linear polymer from the matrix pores during the solvent extraction process on the porous structure was also discussed.     

Preparation and characterization of monodisperse porous silica microspheres with controllable morphology and structure

A novel method for the preparation of monodisperse porous silica microspheres with controllable morphology and structure is reported. The starting porous polymer microspheres were first functionalized with ethylenediamine (EDA) to generate amino groups. Subsequently, silica nanoparticles were deposited in the porous polymer microsphere to form polymer/silica hybrid microspheres via a modified sol‐gel process in the presence of tetra‐n‐butylammonium bromide (TBAB) or tetramethyl ammonium hydroxide (TMAH). Upon calcination of the polymer/silica hybrid microspheres, the porous silica microspheres were obtained. The morphology, inner structure, and properties of the porous silica microspheres were studied by field emission scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric analysis, and mercury intrusion method. The results show that the presence of TBAB or TMAH in the process not only prevents the agglomeration of the hybrid microspheres, but also governs the controllable morphology from a porous inner structure to a hollow‐cage structure. The obtained porous silica microspheres exhibit no shrinkage from the polymer microspheres with a yield of around 98%. These porous silica microspheres have potential applications in the fields of chromatography, catalyst, and biology. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Core-shell copper hydroxide-polysaccharide composites with hierarchical macroporosity

A new method of preparation of polymeric-inorganic porous nanocomposites with core-shell morphology allowed to stabilise copper hydroxide salts in water. A shell of inorganic salts was formed around microspheres of alginate gel by migration of the metal ions from the core of the particles. The formation of the copper hydroxide nitrate shell was controlled by the kind of mineralisation treatment. The natural polysaccharide was an effective agent of inorganic growth control. The mineral shell stabilised the hydrated polymer gel by considerably limiting the drying and induced the formation of a hierarchical macroporosity when drying the microspheres under supercritical CO₂ conditions.     

超临界CO2中的高分子合成研究进展

本文介绍以超临界CO₂流体为介质的高分子合成的研究进展。说明可在超临界二氧化碳中实施氟代单体的自由基溶液聚合、甲基丙烯酸甲酯和苯乙烯的分散聚合、丙烯酸的沉淀聚合、丙烯酰胺的反相乳液聚合以及异丁基乙烯基醚的阳离子聚合等多种聚合反应。这显示出超临界CO₂是一种对环境无污染且价廉的替代溶剂。     

Preparation and pore-size control of hydrophilic monodispersed polymer microspheres for size-exclusive separation of biomolecules by the SPG membrane emulsification technique

This paper describes an experiment directed toward the preparation of monodispersed porous polymer microspheres with a diameter of ca. 50 m, which is applicable to the chromatographic separation of biomolecules such as proteins and peptides by size exclusion. Fairly monodispersed polymer microspheres were successfully prepared by suspension copolymerization of polyethylene glycol monomethacrylate and ethylene glycol dimethacrylate as monomer and cross-linker, respectively. Monodispersed O/W emulsion was prepared by the SPG membrane emulsification technique, and was used in the subsequent droplet-swelling process in which monodispersed seed droplets were swollen by adsorbing the secondary emulsion droplets. The effects of the organic diluent in suspension polymerization and comonomer on the porous structure of the polymer microspheres were investigated by scanning electron microscopy and mercury-intrusion porosimetry, and the separation performances of polystyrene, polyethylene glycol, and various biomolecules by size-exclusion chromatography. As a result, it was evident that benzene, 1-butanol, and butyl acetate worked as nonsolvents for the polymer prepared in this study, and that polymer microspheres prepared with these solvents had larger pores. Size-exclusion chromatography revealed that the exclusive limiting molecular weight was 1.9×10⁵ when polystyrene was used as a standard polymer, and 3.5×10⁴ when polyethylene glycol was used as a standard polymer. Furthermore, we confirmed that the monodispersed polymer microspheres with defined pores clearly separated the six representative kinds of biomolecules with molecular weights ranging from 75 to 6.4×10⁵.