复合Fe2O3纳米粒子的高分子微球的结构表征

近年来，复合有机、无机粒子的高分子微球及其特殊性质越来越引起人们的兴趣与关注［1］．获得有机、无机复合微球的方法很多，如在无机粒子存在下的乳液或无皂乳液聚会[2，3]，通过可聚合的表面活性剂在粒子表面形成胶囊化层[4]以及共沉淀法等[5]．这些无机粒子包括氧化钛、氧化铁、氧化铝及氧化硅等．Haga等[6]增发现包覆在聚合物粒子中的CdS与其本体的光电性质不同；单分散的聚合物微球可以在基片上被组装成二维乃至三维有序的结构[7]．这为信息存储、立体印刷等领域提供了新途径．因此，将无机粒子与聚合物复合成为功能化粒子是一项有…     

含C60聚苯乙烯微球的制备及光电导性能研究

目前,多功能、高性能聚合物微球的合成及应用已成为研究热点.制备聚合物微球的方法有乳液聚合法、分散聚合法、无皂乳液聚合法、超微乳液聚合法和悬浮聚合法等.制备微米级微球通常采用乳液聚合法和分散聚合法.     

不良溶剂氛围中用breath figures法制备聚合物微球

通过使用操作简单、不需去除模板也不需使用乳化剂的breath figures(BFs)法,在多种非水氛围中制得聚合物微球,如丙烯腈-丙烯酸甲酯-苯乙烯三元共聚物(ASA)和聚丁二酸丁二醇酯(PBS)等;并研究了聚合物溶液浓度、不同氛围等对微球形貌的影响.结果表明,以甲醇、乙醇和正己烷为氛围时均可制得聚合物微球,而在乙酸中得到的是聚合物多孔膜.在乙醇氛围中随着聚合物浓度的增加,微球逐渐黏结,均一性变差;随着乙醇氛围中水含量的增加,形貌由微球过渡到微孔膜.     

微波合成均分散高分子微球及其机理

微米级大粒径单分散高分子微球在标准计量、情报信息、分析化学等许多领域都有广泛的应用前景［１］,在临床检验和诊断、免疫技术、细胞学研究以及血液循环等生物医学领域也发挥了极大作用［２］．在微球的各种特性中,影响其应用的重要因素是微球的尺寸、分散性及形态等,因此对微球的尺寸和均匀性的控制就显得十分重要,对其形成机理的研究也很有意义,对此已有许多实验和理论的报导［３－６］．在微波辐射条件下,采取种子聚合法合成高分子微球,可以得到不同尺寸的粒子,并且有很好的分散性,比普通加热条件下反应时间大大缩短,所得数…     

热敏性高分子包裹的磁性微球的合成

磁性高分子微球由于其在外加磁场作用下简单、快速易行的磁分离特性，其在细胞分离、固定化酶、靶向药物等领域的应用研究日益活跃，并显示出较好的应用前景［１］．有关文献报道了制备磁性微球的不同方法［２］．Ｎ 异丙基丙烯酰胺（Ｎ ｉｓｏｐｒｏｐｙｌａｃｒｙｌａ...     

用微波加热法制备纳米级磷酸钴球粒

用微波加热法制备纳米级磷酸钴球粒董吉溪，张文敏（安徽师范大学化学系芜湖２４１０００）纳米级磷酸盐粒子的制备方法中有均相沉淀法￣［１］，但此方法须经长时间高温陈化过程。Ｋａｎｄｏｒｉ等人指出：将含有硫酸钴的混合溶液在８０℃温度下陈化，可制得均匀分散的球...     

乳液聚合法制备亚微米级分子印迹聚合物微球

以西咪替丁为印迹分子，2-丙烯酰胺-2-甲基丙磺酸(AMPS)为功能单体，三羟甲基丙烷三甲基丙烯酸甲酯(TRIM)为交联剂，采用乳液聚合法制备了亚微米级分子印迹聚合物微球．利用扫描电镜对此聚合物微球的形貌进行了观察，探讨了影响乳液稳定性、粒径大小与分布的主要因素，重点对聚合工艺和配方进行了优化，并将所得的聚合物用作吸附剂研究了其分子识别与选择性能．研究表明，乳液聚合法能够制得单分散性较好的、平均粒径在0．169μm～0．407μm的分子印迹聚合物微球，且该微球对其印迹分子呈现出较好的特异识别与选择性能，当以苯丙氨酸为竞争分子时，分离因子可达1．70．     

种子溶胀悬浮聚合法制备分子印迹聚合物微球

 以酪氨酸为印迹分子 ,甲基丙烯酸为功能单体 ,三羟甲基丙烷三甲基丙烯酸酯 (TRIM )为交联剂 ,采用种子溶胀悬浮聚合法在水溶液中制备了一系列分子印迹聚合物微球 (MIPMs)。利用扫描电镜 (SEM)对此微球的粒径大小、粒径分布、表面孔与孔径分布等进行了分析研究 ,探讨了影响其形貌的主要因素 ,并将所得微球用作固定相研究了其分子选择吸附性能。研究表明 ,种子溶胀悬浮聚合法能够制得单分散性较好的、表面带有微孔的分子印迹聚合物微球 ,且该微球呈现出较好的特异吸附性能。     

用原子转移自由基聚合法合成末端含碳笼烯-60的窄分子量分布聚苯乙烯

Ｃ６０是碳笼烯一族的代表,其独特的球笼形空间结构和电子结构决定了其有许多奇异的性质［１］．关于Ｃ６０的化学反应性的研究方兴未艾［２］,其中Ｃ６０的高分子衍生物的合成也是关注所在．迄今关于含Ｃ６０的高聚物的合成已有许多报道［３,４］,而关于窄分布的含Ｃ６０高聚物的合成的研究尚少．Ｆｒｅｙ等［５］将阴离子聚合所得的聚苯乙烯链的末端转变为氨基,再与过量的Ｃ６０发生单电子转移加成反应制得窄分布的以Ｃ６０封端的聚苯乙烯．Ａｓｔｒｕｓ等［６］将活性阳离子聚合所得的六臂星形聚苯乙烯的末端转化为氨基,得到Ｃ６０…     

纳米超微电极的研究（Ⅳ）—超微金柱电极的制作与表征

纳米超微电极的研究（Ⅳ）──超微金柱电极的制作与表征张学记，万其进，张悟铭，周性尧（武汉大学化学系，武汉，４３００７２）关键词微电极，纳米超微电极，伏安法，离子束，金纤维最近，纳米超微电极［１～５］的研制成功，使超微电极的研究进入一个新阶段，给电化学...     

Model filled polymers. V. Synthesis of crosslinked monodisperse polymethacrylate beads

Monodisperse polymethacrylate beads of varied size and crosslink density are prepared by emulsion copolymerization of methacrylate and divinyl monomers in the absence of emulsifiers. The sizes of polybutyl and polyethyl methacrylate beads decreased with increasing polymerization temperature, while polymethyl methacrylate beads were largely unchanged in size. The molar mass of polymer in polymethyl metnacrylate beads markedly exceeded that in polystyrene beads. The rate of polymerization increased, and bead size decreased, with increasing initiator concentration or decreasing monomer concentration. The polymethacrylate beads are used as filler particles in polymer composites.     

Preparation of macroporous functionalized polymer beads by a multistep polymerization and their application in zirconocene catalysts for ethylene polymerization

Macroporous functionalized polymer beads of poly(4‐vinylpyridine‐co‐1,4‐divinylbenzene) [P(VPy‐co‐DVB)] were prepared by a multistep polymerization, including a polystyrene (PS) shape template by emulsifier‐free emulsion polymerization, linear PS seeds by staged template suspension polymerization, and macroporous functionalized polymer beads of P(VPy‐co‐DVB) by multistep seeded polymerization. The polymer beads, having a cellular texture, were made of many small, spherical particles. The bead size was 10–50 μm, and the pore size was 0.1–1.5 μm. The polymer beads were used as supports for zirconocene catalysts in ethylene polymerization. They were very different from traditional polymer supports. The polymer beads could be exfoliated to yield many spherical particles dispersed in the resulting polyethylene particles during ethylene polymerization. The influence of the polymer beads on the catalytic behavior of the supported catalyst and morphology of the resulting polyethylene was investigated. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 873–880, 2003     

Preparation and functionalization of reactive monodisperse macroporous poly(chloromethylstyrene-co-styrene-co-divinylbenzene) beads by a staged templated suspension polymerization

Reactive monodisperse porous poly(chloromethylstyrene-co-styrene-co-divinylbenzene) beads have been prepared by a staged templated suspension polymerization method with different concentrations of linear polystyrene porogen and chloromethylstyrene in the polymerization mixture. The presence of a small amount of linear polystyrene in the polymerization mixture leads to a dramatic increase in both the pore size and the pore volume of the resulting beads. In contrast, addition of chloromethylstyrene leads to lower surface areas and smoother surfaces due to the reduced compatibility between the polystyrene porogen and the newly formed crosslinked chains. The modification of chloromethylstyrene beads by Gabriel synthesis to obtain aminated beads has also been studied. The final number of primary amino groups is related to the starting concentration of functional benzyl chloride moieties rather than to the porous properties. Both π-basic and π-acidic type chiral selectors, (R)-1-(1-naphthyl)-ethylamine and (R)-N-(3,5-dinitrobenzoyl)phenylglycine, respectively, have been attached to the amino functionalized beads, and the resulting chiral beads have been used in the model HPLC separations of enantiomers. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2631–2643 1997     

带羧基单分散彩色微球的制备

采用两步活性溶胀种子聚合法, 制备了可用于免疫检测的3种不同颜色的表面带有羧基功能基的粒径在400—800 nm之间的彩色单分散微球. 先用无皂乳液聚合法制备出单分散聚苯乙烯种子, 然后用邻苯二甲酸二正丁酯(DBP)作为溶胀剂对微球进行溶胀, 溶涨后的种子模板再用混溶的苯乙烯、二乙烯苯、丙烯酸、双键彩色染料以及引发剂(BPO)溶胀, 升温聚合后得到理想的单分散微球. 考察了DBP和单体用量、各单体配比及染料对微球的形貌和单分散性的影响.     

Model filled polymers. VIII. Synthesis of crosslinked polymeric beads by seed polymerization

Monodisperse crosslinked polystyrene (PS) and polymethacrylate (PMA) beads of sizes greater than 1 μm in diameter are prepared by particle nucleation onto pre-existing polymer seeds in a multistage emulsion polymerization, in the absence of emulsifier. An adequate seed number concentration, which decreases with increasing seed size, is necessary to achieve monodisperse beads. Monodisperse multicomposition beads are prepared by polymerizing styrene onto PMA seeds, but not by polymerizing methyl methacrylate onto PS seeds. Phase separation in growing seed particles or surface polymerization following free radical capture may lead to the formation of asymmetric shaped particles.     

Cross-linked starch nanoparticles stabilized Pickering emulsion polymerization of styrene in w/o/w system

Here, we present a method to synthesize expandable spherical polystyrene beads containing well-dispersed water microdroplets. The beads, 2–3 mm in diameter, were prepared through surfactant-free Pickering emulsion polymerization in water-in-oil-in-water (w/o/w) system using cross-linked starch nanoparticles (CSTN) as emulsifier. The CSTNs were in situ surface-modified by styrene maleic anhydride copolymer as confirmed by infrared spectroscopy and contact angle analysis. The entrapped water microdroplets with the average size of 3–4 μm were shown to be surrounded by a dense layer of the CSTN. The number droplet density as well as water encapsulation efficiency in the polystyrene beads increased with the CSTN concentration. Furthermore, regardless of CSTN content, all samples exhibited high encapsulation stability of over 68 % after 3 months. These characteristics along with good expansion behavior suggest the synthesized beads as expandable polystyrene containing water as a green blowing agent.     

Organized monolayer of thermosensitive microgel beads prepared by double-template polymerization

A 2D close-packed array of thermosensitive microgel beads was prepared by the double-template polymerization method. First, a 2D colloidal crystal of silica beads with 10 microm diameter was obtained by the solvent evaporation method. This monolayer of colloidal crystals can serve as the first template for the preparation of macroporous polystyrene. The macroporous polystyrene trapping the crystalline order can be used as a negative template for fabricating gel beads arrays. A functional surface using thermosensitive poly(N-isopropylacrylamide) gel beads array was fabricated by the double-template polymerization method.     

Synthesis of polystyrene beads loaded with dual luminophors for self-referenced oxygen sensing

Dispersion polymerization has been successfully applied to synthesize monodisperse polystyrene beads loaded with SiOEP and PtOEP for self-referenced oxygen sensing. The polystyrene beads became larger in size as the concentration of initiator was increased due to the reduction of primary particles precipitated from the polymerization medium. The dual luminophors showed similar absorption spectra but two distinctive emission spectra with peaks at 580 and 650 nm for SiOEP and PtOEP, respectively. While the emission of SiOEP exhibited no response to oxygen, the luminescence intensity of PtOEP was monotonically dependent on the concentration of oxygen. From the Stern-Volmer plot, we observed a linear correlation between the intensity ratio of SiOEP at 580 nm to PtOEP at 650 nm and the concentration of oxygen, which could be used to reliably monitor the partial pressure of oxygen in a system.     

Synthesis of Latex Particles with Surface Functional Groups and Their Applications for the Fabrication of Porous Materials

In this study, monodisperse latex particles with specific surface functional groups were synthesized by emulsifier-free emulsion polymerization. Amidine or carboxylated polystyrene nanospheres with narrow size distribution were prepared by emulsion polymerization using AIBA (α,α′-zodiisobutyramidine dihydrochloride) as amine-containing initiator or acrylic acid as carboxyl-containing comonomer, respectively. Factors affecting the particle size and distribution were systemically studied by changing the amount of initiator or monomer, the polymerization temperature, and the stirring speed of emulsion polymerization reactor. Monodisperse polymethylmethacrylate beads were also synthesized by soapless emulsion polymerization using methacrylic acid or aminoethylmethacrylate hydrogen hydrochloride as comonomer for the surface functionalization of the particles. As applications of the latex beads, the polymeric particles were adopted as templating materials for the fabrication of macroporous titania film and meso-macroporous silica particles by colloidal templating method.     

Pore size in one‐step swelling and polymerization of monodisperse polymer beads

Crosslinked polystyrene beads were prepared at low swelling ratios by one‐step swelling and polymerization method. Pore size of the beads was observed based on the GPC calibration curves. It is found that: (1) the pore size increases as the swelling ratio decreases; (2) when a good solvent is used as the porogen the pore size increases with the crosslinking monomer content; and (3) at high crosslinking monomer content the pore size does not depend on the porogen solubility. The effects are discussed in terms of polymer miscibility, including phase separation between the seed and bead polymers. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3270–3277, 2000