Surface characterization of styrene/2-hydroxyethyl methacrylate copolymer latex

Styrene/2-hydroxyethyl methacrylate copolymer (PS/PHEMA) latex was prepared without soap. From an electron micrograph, this latex was found to be highly monodisperse. The surface characterization of PS/PHEMA latex was compared with that of polystyrene (PS) latex. Conductometric titration curves of these latexes revealed that both strong and weak acid groups existed on the latex surface. It was found that pH dependence of surface charges for these latexes was not very pronounced whereas negative values of ζ- potentials for PS/PHEMA latex were smaller than that for PS latex over the whole range of measured pH. This was interpreted on the basis of the difference in the structure of the electrical double layer for these latexes. Methylene Blue adsorption onto PS and PS/PHEMA latexes was measured as a function of pH, too. The pH dependence of the dye adsorption onto these latexes was hardly discernible. However, the amount of Methylene Blue adsorbed was somewhat greater onto PS latex than onto PS/PHEMA latex. This result might be attributed to the strength of hydrophobic interaction between dye and latex. It was suggested that PS/PHEMA latex was more hydrophilic than PS latex in spite of having about the same surface charge as PS latex.     

Formation of dual-responsive polystyrene/polyaniline microspheres with sea urchin-like and core-shell morphologies

In the present work, a simple and effective approach has been employed to fabricate the polystyrene/polyaniline (PS/PANI) composite microspheres with various morphologies. PS/PANI composite microspheres exhibiting different structures such as sea-urchin like, core-shell structure, have been synthesized by seeded emulsion polymerization with polystyrene microspheres as seeds. In particular, the sea urchin-like PS/PANI composite microspheres, with radial array nanofibers on the surface, have demonstrated the switchable wettability between superhydrophilicity (0°) and superhydrophobicity (152°) under the response of either electrical potential or pH. This intelligible approach can produce sea urchin-like PS/PANI composite microspheres in bulk. The growth mechanism of sea urchin-like PS/PANI composite microspheres has also been elucidated. Following the dissolution of the PS template, the sea urchin-like polyaniline (PANI) hollow microspheres are obtained.     

Pickering乳液聚合法CdS/PS荧光复合微球的制备与表征

通过水相合成法制备水溶性硫化镉(CdS)纳米晶,以CdS纳米晶固体粒子为乳化剂,进行Pickering乳液聚合制得CdS/PS荧光复合微球。通过SEM、XRD、FTIR、UV-vis、PL对CdS/PS荧光复合微球的微观结构、结晶情况及光学性能进行了分析和表征。结果表明,该复合微球具有以PS为核、CdS纳米晶为壳的核壳结构;复合微球的平均粒径为450nm;在复合微球中,CdS纳米晶仍然保持其量子尺寸效应,复合微球表现出了较好的荧光性能。     

Synthesis and characterization of uniform polyepoxide micrometer sized particles by redox graft polymerization of glycidyl methacylate on oxidized polystyrene and polydivinylbenzene microspheres for enzyme immobilization

Polystyrene template microspheres of narrow size distribution were prepared by dispersion polymerization of styrene in 2-methoxyethanol. Uniform polystyrene/poly(divinyl benzene) composite microspheres were formed by a single-step swelling process of the polystyrene template microspheres with dibutyl phthalate droplets containing divinyl benzene and benzoyl peroxide, followed by polymerization at 73 °C. Uniform poly(divinyl benzene) microspheres of higher surface area were produced by dissolution of the template polystyrene part of the former composite microspheres with methylene chloride. Hydroperoxide conjugated polystyrene and poly(divinyl benzene) microspheres were produced by controlled ozonolysis of these microspheres. Polyepoxide conjugated microspheres were then formed by redox graft polymerization of glycidyl methacylate on the hydroperoxide-conjugated microspheres. Microspheres with different properties, e.g., size, size distribution, shape, surface morphology, surface area, etc., have been prepared by changing various parameters belonging to the ozonolysis and the grafting polymerization processes, e.g., ozonolysis conditions and monomer volume. Trypsin was then covalently bound to the polyepoxide conjugated microspheres by interacting the epoxide groups of the particles with primary amino groups of the enzyme. A comparison between the enzymatic activity of the conjugated and the free trypsin was also established.     

二氧化钛纳米管稳定Pickering乳液制备PS/TiO2纳米管复合微球

利用γ-甲基丙烯酰氧基丙基三甲氧基硅烷（KH-570）,对水热法制备的TiO₂纳米管进行了表面改性,并用改性的纳米管为稳定剂,采用Pickering乳液聚合法制备了聚苯乙烯/TiO₂纳米管复合微球。采用红外光谱（IR）、光学显微镜、高分辨透射电镜（HRTEM）、高分辨扫描电子显微镜（FESEM）、X射线光电子能谱（XPS）等分析手段,对改性前后TiO₂纳米管以及复合微球的结构和形貌进行了表征,用三相接触角仪测试并优化了TiO₂纳米管的表面润湿性。研究结果表明,当m_KH-570/m_TiO2=15%时,改性TiO₂纳米管表面润湿性最佳,能很好地稳定Pickering乳液聚合,聚合后可以得到壳层为致密均匀TiO₂纳米管,核为聚苯乙烯的复合微球。     

Fabrication of anisotropic janus composite particles based on natural renewable urushiol

Urushiol praseodymium‐polystyrene (UPr‐PS) Janus composite particles were synthesized by emulsion swelling assisted protruding from UPr/PS core‐shell composite microspheres. The effects of sulfonated time and the outer electronic configuration of metal on the shell of urushiol metal/PS composite microspheres, together with the effects of monomer type, monomer dosage and swelling time on the swelling behaviour, were studied. The morphology, chemical composition and thermal performance of UPr/PS core‐shell composite microspheres and UPr‐PS Janus composite particles were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X‐ray analyzer (EDX), Thermogravimetric analysis (TG) and infrared spectrometer (IR). Results showed that the morphology could be controlled by the metal kind, the sulfonated time, the monomer type, the monomer dosage and the swelling time. Attributing to the novel anisotropic structure, the UPr‐PS Janus composite particles will be expected to be applied in oriented catalyst. POLYM. ENG. SCI., 59:411–417, 2019. © 2018 Society of Plastics Engineers     

Synthesis and properties of amphiphilic nonspherical SPS/PS composite particles by multi-step seeded swelling polymerization

Amphiphilic nonspherical particles have asymmetric surface physical and chemical properties. Such a unique structure makes them suitable for applications in many areas, such as chemical and biological sensors, colloidal surfactants, self-assembly, building blocks of complex superstructures, and materials engineering. In this study, amphiphilic sulfonated polystyrene/polystyrene (SPS/PS) composite particles with controllable morphologies are synthesized by combining modified treatment and multistage seeded swelling polymerization. Core-shell SPS particles were first obtained by modifying cross-linked PS particles with concentrated sulfuric acid, and the surface of SPS particles was a hydrophilic sulfonated polystyrene layer. With further twice seeded swelling polymerization, new hydrophobic PS oil phase sprouted on the strong hydrophilic surface even without any surfactant assistance in aqueous media. The morphologies of these SPS/PS composite particles could be adjusted by changing the crosslinking density of the seed microspheres, the sulfonation temperature and the swelling ratio of monomer/seed. These polymer composite particles can be used as solid surfactants.     

Synthesis of Low-Density Heat-Resisting Polystyrene/Graphite Composite Microspheres Used as Water Carrying Fracturing Proppants

Low-density heat resistamt, low-cost polystyrene (PS)/graphite microspheres were successfully synthesized via in situ suspension polymerization. Scanning electron microscopy (SEM) indicated that PS/graphite composite microspheres had good sphericity, and graphite particles were evenly dispersed in microspheres. Furthermore, density analysis illustrated that the density of composites was about 1.025–1.185 g/cm³ with good suitability for carrying water. Thermodynamic testing revealed that the thermostability of the composite was dramatically improved by the introduction of graphite, which is used deep underground. In addition, the percentage of damage decreased to 1.3% with graphite ratio of 2.5% at 68 MPa. Therefore, PS/Graphite composite microspheres possess entirely feasible applications in oil exploitation as pure water carrying petroleum proppants.     

原位乳液聚合法制备二氧化钛/聚苯乙烯复合微球

采用原位乳液聚合法制备了TiO2 PS(二氧化钛 聚苯乙烯)复合微球,探索了复合微球的制备条件,并采用红外、透射电镜和差热分析等分析手段对其结构进行了表征。结果表明,采用原位乳液聚合法可制备出粒径分布均一的不同粒径的TiO2 PS复合微球,反应条件对微球的形成及粒径影响很大,介质pH>7以及乳化剂用量小于临界胶束浓度是形成复合微球的必要条件;复合微球粒径随苯乙烯浓度增加而增大。     

聚苯乙烯/无机粒子(核/壳)复合微球的制备与研究进展

综述了近年来国内外聚苯乙烯(PS)/无机粒子(核/壳)复合微球的制备方法,如化学沉积法、静电自组装法和化学镀法等,简述了PS/无机粒子(核/壳)复合微球的优异性能及其应用,展望了PS/无机粒子(核/壳)复合微球的发展前景。     

Preparation of monodisperse magnetic polystyrene microspheres and its surface chemical modification

Monodisperse magnetic polystyrene (PS) microspheres were prepared in the presence of PS seed particles and styrene‐based magnetic colloid by the method of magnetic colloid swelling polymerization. The PS seed particles were prepared in advance by soap‐free emulsion polymerization. Styrene‐based magnetic colloid was used for swelling the PS seed particles in the magnetic colloid swelling polymerization process. After polymerization, functional amino groups were introduced onto the surface of the magnetic PS microspheres by surface Friedel‐Crafts acylation reaction. The morphology, size distribution, and magnetic properties of magnetic PS microspheres were characterized with scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM), respectively. SEM showed that the magnetic PS microspheres had an average size of 1078 nm with a narrow size distribution. VSM showed that the magnetic PS microspheres were superparamagnetic, and saturation magnetization was found to be 5.714 emu/g. The concentration of functional amino groups on the surface of magnetic PS microspheres was measured by atomic absorption spectroscopy and UV−Vis spectroscopy, and the concentration of amino groups was found to be 0.168 mmol/g. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

聚合物/SiO2核壳结构单分散微球的制备

聚合物/SiO2核壳结构单分散微球比聚合物微球具有更好的稳定性,有望在较高的温度和有机溶剂中得到使用.为了制备出这种微球,作为模板的聚合物微球首先进行表面胺化处理,然后正硅酸乙酯被诱导在其表层水解缩合从而形成SiO2壳层;采用扫描电子显微镜(SEM)、傅里叶红外光谱仪(FTIR)、激光粒度仪,烧蚀质量损失等手段分析表征...     

Heparin‐immobilized poly(2‐hydroxyethylmethacrylate)‐based microspheres

Poly(2‐hydroxyethylmethacrylate) (PHEMA)‐based microspheres (150–200 µm in diameter) were produced by a modified suspension polymerization of different type of comonomers—namely, acrylic acid, dimethylaminoethyl‐methacrylate, and methylmethacrylate. These microspheres were activated with cyanogen bromide (CNBr) at pH 11.5, and heparin molecules were then immobilized through covalent bonds. The amount of immobilized heparin was controlled by changing the initial concentration of CNBr and heparin. The increase in the initial concentrations of both CNBr and heparin caused an increase in the amount of heparin immobilized onto microspheres for all polymer surfaces. The maximum heparin immobilization was observed on the PHEMA homopolymer microspheres (180 mg/g). The plain and heparin‐immobilized microspheres were contacted with blood in in vitro systems and in ex vivo animal experiments. Loss of the blood cells and clotting times were followed. Anticoagulant effect of the immobilized heparin was clearly observed with blood coagulation experiments. Loss of cells in the blood contacting with heparin‐immobilized microspheres was significantly lower than those observed with the plain microspheres. Bovine serum albumin adsorption onto the microspheres containing heparin on their surfaces was also studied. High albumin adsorption values (up to 127 mg/g) were observed in which the heparin‐immobilized PHEMA microspheres were used. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 655–662, 1999     

Chemical coating polysaccharide on gigaporous polystyrene microspheres as a high‐speed protein chromatography matrix

Permanent polysaccharide coating on gigaporous polystyrene (PS) microspheres was achieved through direct chemical grafting of dextran via a facile method, minimizing nonspecific adsorption of proteins and providing easily derivatizable groups on microspheres. Chloroacetylated PS microspheres (PS‐Cl) were first developed through acetylation, and hydrophilic dextran was directly grafted to hydrophobic PS‐Cl via a Williamson reaction (PS‐Dex). The homogeneous side‐bound dextran coating has the advantage of masking the hydrophobic surface of the PS microspheres, while maintains their original gigaporous structure. After grafting, the hydrophobic surface of the PS microspheres was effectively masked, and nonspecific protein adsorption was greatly reduced. Moreover, the hydroxyl‐rich coating can be easily derivatized through classical chemical methods. A column packed with PS‐Dex presented both good permeability and mechanical strength at high flow velocities of up to 3612 cm/h. These results implied that PS‐Dex should be an ideal matrix for high‐speed protein chromatography. POLYM. ENG. SCI., 56:1407–1414, 2016. © 2016 Society of Plastics Engineers     

Preparation and characterization of core‐shell PS/Ni composite microspheres

PS/Ni microspheres were prepared by electroless nickel plating on PS microspheres. Several parameters for plating were optimized in order to obtain integrated and uniform nickel coatings. The properties of obtained composite microspheres, such as chemical composition and crystal texture of the coating, mechanical property, density, and magnetism, were characterized by SEM, EDS, XRD, and VSM. It was revealed that several parameters, such as thiourea dosage, reaction temperature, and load, had significant influence on fabrication of integrated and homogeneous nickel shell. It was also demonstrated that the properties of the PS/Ni microspheres, such as nickel weight ratio, density, and magnetism, can be tuned by adjusting the load. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

包覆型CeO_2/SiO_2和CeO_2/聚苯乙烯复合磨料的制备及其化学机械抛光性能

以SiO2和聚苯乙烯(polystyrene,PS)微球为内核,采用液相沉淀工艺制备了具有包覆结构的CeO2/SiO2和CeO2/PS复合颗粒。利用X射线衍射仪、透射电子显微镜、场发射扫描电子显微镜、X射线光电子能谱仪、动态光散射仪和zata电位测定等手段对所制备样品进行了表征。将所制备的CeO2/SiO2和CeO2/PS复合颗粒用于硅晶片热氧化层的化学机械抛光,用原子力显微镜(atomic force microscope,AFM)观察抛光表面的微观形貌、测量表面粗糙度。结果表明:所制备的CeO2/SiO2和CeO2/PS复合颗粒呈球形,粒径在150～200nm,CeO2纳米颗粒在SiO2和PS微球内核表面包覆均匀。包覆的CeO2颗粒与SiO2内核之间形成了化学键结合。CeO2颗粒的包覆显著的改变了复合颗粒的表面电性。AFM测量结果表明:经CeO2/SiO2和CeO2/PS复合磨料抛光后的硅热氧化片表面在5μm×5μm范围内粗糙度值分别为0.292nm和0.180nm。     

单分散氢氧化钙/聚苯乙烯微球的制备与表征

以葡萄糖水溶液为反应介质,在氧化钙消化成氢氧化钙的过程中,加入苯乙烯单体和引发剂,采用原位悬浮聚合法成功制备了聚苯乙烯(PS)包覆氢氧化钙[Ca(OH)2]形成Ca(OH)2/PS微球.考察了葡萄糖水溶液、苯乙烯、稳定剂聚乙烯醇以及反应温度对单分散Ca(OH)2/PS微球的粒径及粒子分散系数的影响,得出较佳合成条件.在较佳条件下制备的Ca(OH)2/PS微球平均粒径为30～40 μm,粒子分散系数为0.08～0.10.扫描电镜照片表明,Ca(OH)2/PS具有良好的球形度,表面光滑、无破损.红外光谱表征显示,产物为Ca(OH)2/PS微球.     

细乳液聚合制备二氧化钛/聚苯乙烯复合微球及其形貌分析

采用细乳液聚合法,以γ-甲基丙烯酰氧基丙基三甲基硅烷改性的TiO2粒子为核,制备了核壳结构的TiO2/聚苯乙烯(PS)复合微球。研究了超声细乳化时间、乳化剂十二烷基硫酸钠(SDS)的浓度、TiO2用量对细乳液粒径及其分布的影响。通过纳米粒度与Zeta电位分析仪、红外光谱、透射电镜等分析手段对产物进行了表征。结果表明,随着超声细乳化时间的增加,初始液滴的粒径变小。聚合后的乳胶粒粒径随着SDS浓度的增大而减小;TiO2用量不足导致乳胶粒粒径分布变宽,且出现双峰;制备所得的TiO2/PS复合微球粒度分布较为均匀,平均直径为176.5 nm,球形规整度较好。     

Composite magnetic particles: 1. Deposition of magnetite by heterocoagulation method

In this paper we report synthesis and characterization of composite polymeric particles bearing magnetite inclusions and reactive β-diketone groups on the surface. Composites were prepared by two-step method in which first step requires preparation of the functionalized polystyrene core and during second step magnetite was deposited onto core particle surface. This procedure gives a possibility to obtain composite particles with core-shell morphology and both the core size and magnetite shell thickness can be varied. Highly monodisperse PS/AAEM microspheres were synthesized by surfactant-free emulsion polymerization. Change of monomer fleet-ratio gives a possibility to change effectively the final particle size of dispersions without strong changes in particle size distribution. PS/AAEM particles were characterized by light scattering techniques (DLS, SLS) and electron microscopy (SEM) with respect to their particle size and morphology of the surface layer. Magnetite was deposited in form of nano-crystals onto PS-AAEM particle surface by heterocoagulation process. It has been established that more uniform magnetite coating was obtained at lower base amounts used for synthesis of magnetite. Amount of the magnetite on the polymeric particle surface can be effectively controlled by changing the initial FeCl₂ and FeCl₃ concentrations and/or variation of the PS/AAEM core dimensions. It has been confirmed by separation centrifugation technique, that stepwise increase of the magnetite content on the particle surface decrease gradually the stability of colloidal system. Magnetization curves for composite particles indicate that deposited magnetite content is high enough to achieve considerable magnetic response to external magnetic field.     

核-壳型聚苯乙烯/二氧化硅复合微球的制备

利用层层自组装的方法制备了粒径和组成可裁剪、具有核-壳式结构的单分散聚苯乙烯(PS)／二氧化硅(SiO2)复合微球．对复合微球进行热处理除去有机物中心，制备出壁厚可剪裁的空腔硅球，并对复合微球的热分解过程进行了研究．透射电镜(TEM)照片显示二氧化硅纳米颗粒在中心外生成均匀壳层，而煅烧后则可得到轮廓分明的球形空腔；比较PS，SiO2和复合球体及热处理后的粉体的红外光谱，可分别验证二氧化硅的成功组装和热处理过程中作为中心的PS的完全去除．在吸附相同层数的前提下，随着所选用的二氧化硅纳米粒子的粒径的增大(10-40nm)，复合微球的粒径增大，空腔球体的壁厚增加，中心粒子热分解的活化能增大．复合微球的热分解机理符合三维扩散机理．