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Polystyrene Microbeads by Dispersion Polymerization: Effect of Solvent on Particle Morphology  [PDF]
Lei Jinhua,Zhou Guangyuan
International Journal of Polymer Science , 2014, DOI: 10.1155/2014/703205
Abstract: Polystyrene microspheres (PS) were synthesized by dispersion polymerization in ethanol/2-Methoxyethanol (EtOH/EGME) blend solvent using styrene (St) as monomer, azobisisobutyronitrile (AIBN) as initiator, and PVP (polyvinylpyrrolidone) K-30 as stabilizer. The typical recipe of dispersion polymerization is as follows: St/Solvent/AIBN/PVP = 10?g/88?g/0.1?g/2?g. The morphology of polystyrene microspheres was characterized by the scanning electron microscopy (SEM) and the molecular weights of PS particles were measured by the Ubbelohde viscometer method. The effect of ethanol content in the blend solvent on the morphology and molecular weight of polystyrene was studied. We found that the size of polystyrene microspheres increased and the molecular weight of polystyrene microspheres decreased with the decreasing of the ethanol content in the blend solvent from 100?wt% to 0?wt%. What is more, the size monodispersity of polystyrene microspheres was quite good when the pure ethanol or pure 2-Methoxyethanol was used; however when the blend ethanol/2-Methoxyethanol solvent was used, the polystyrene microspheres became polydisperse. We further found that the monodispersity of polystyrene microspheres can be significantly improved by adding a small amount of water into the blend solvent; the particles became monodisperse when the content of water in the blend solvent was up to 2?wt%. 1. Introduction Micrometer-size monodisperse polymer particles have a wide variety of scientific and technological applications, such as standard calibration, biomedical and clinical diagnosis, high-performance liquid chromatography (HPLC) fillers, catalyst carriers, coatings and ink additives, information storage materials, and colloidal crystals [1, 2]. Micron-size monodisperse particles were usually difficult to obtain because this size is in-between the diameter range of particles produced by conventional emulsion polymerization (0.06–0.7?μm) in a batch process [3–6] and suspension polymerization (50–1000?μm) [7–11]. Dispersion polymerization is an attractive method for producing micron-size monodisperse polymer particles in a single batch process. Great progress in this field has been achieved over the past three decades [12–21]. Dispersion polymerization in organic hydrocarbon media was first developed by Barrett [22]. Dispersion polymerization may be defined as a type of precipitation polymerization in which one carries out the polymerization of a monomer in the presence of a suitable polymeric stabilizer soluble in the reaction medium. The solvent selected as the reaction
Effect of different ligands on the controlled polymerization of monodisperse polystyrene nanospheres by atom transfer radical polymerization in an aqueous emulsion
E. J. Tang,B. Y. Tian,P. J. Hu,M. Yuan
eXPRESS Polymer Letters , 2012, DOI: 10.3144/expresspolymlett.2012.89
Abstract: Polystyrene nanospheres have been synthesized by atom transfer radical polymerization (ATRP) to control the molecular weight distribution in the aqueous system. The crucial factor in such a system is the ligand that adjusts the solubility of the catalyst in different phases to control the concentration of both the activator and the deactivator in reaction phase. The effect of different ligands including ethylenediamine, 1,10-phenanthroline (phen) and 4,4-dinonyl-2, 2-bipyridyl (dNbpy) on the catalytic solubility in the organic and aqueous phase has been investigated. The molecular weight distribution of polymer obtained in this way was analyzed by gel permeation chromatography (GPC). It showed that the obtained polymer particles presented a broad molecular weight distribution (polydispersity index 1.78) with ethylenediamine as the ligand, but the polymerization rate was high and conversion reached 96.8%. The molecular weight distribution of polystyrene was narrowest with dNbpy as ligand, but the conversion was lowest and only achieved to 69%. Possible reasons were the influence of the structure of three different ligands on the control of ATRP reaction. SEM and GPC indicated that the polystyrene nanospheres presented regular sphere with a diameter of about 120 nm and uniform molecular weight distribution, which possessed a significant potentials in drug carrier field.
Polystyrene/nano-SiO2 composite microspheres fabricated by Pickering emulsion polymerization: Preparation, mechanisms and thermal properties
W. H. Zhang,X. D. Fan,W. Tian,W. W. Fan
eXPRESS Polymer Letters , 2012, DOI: 10.3144/expresspolymlett.2012.57
Abstract: We report the preparation, mechanisms and thermal properties of core-shell structured polymer/inorganic nanoparticle composite microspheres prepared by Pickering emulsion polymerization. Stable Pickering emulsion was firstly fabricated by using surface-modified nano-SiO2 particles as stabilizer. And then, two kinds of polystyrene/nano-SiO2 (PS/SiO2) composite microspheres with different sizes and morphologies were synthesized using hydrophobic azobisisobutyronitrile (AIBN) and hydrophilic ammonium persulfate (APS) as initiator, respectively. The possible mechanisms of Pickering emulsion polymerization initiated by different initiators were proposed according to the results of transmission electron microscope (TEM) and scanning electron microscope (SEM). The chemical structure and molecular weight of the composite microspheres were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD) and gel permeation chromatography coupled with a multi-angle laser light scattering photometer (GPC-MALLS). Thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) were used to comparatively analyze the thermal properties of nanocomposites and corresponding pure polymer. The results indicated that the decomposition temperature and glass transition temperature (Tg) of nanocomposites were elevated to a certain degree due to the existence of nano-SiO2.
Photoactive Gold Nanoparticle Soft-oxometalates (SOM) using a Keplerate for Synthesis of Polystyrene Latex Microspheres by Photo-polymerization  [PDF]
Atharva Sahasrabudhe,Soumyajit Roy
Physics , 2014, DOI: 10.1142/S2251237314400024
Abstract: A green and facile synthetic protocol for the preparation of photoactive gold nanoparticle-soft oxometalates (AuNP-SOM) using a unique Keplarate type oxomolybdate cluster viz. {Mo$_{132}$}, is reported. The as synthesized AuNP-SOMs are fully characterized by Electronic absorption spectroscopy, Raman spectroscopy and High resolution transmission electron microscopy (HR-TEM). We further demonstrate that by merely tuning the ratio of the precursors in solution it is possible to control the morphology of AuNP-SOM nanostructures. Moreover, these photoactive AuNP-SOMs are employed as photocatalysts for the photopolymerization of styrene to generate colloidal monodisperse polystyrene microspheres in a controllable way in the absence of any external co-initiator or inert atmosphere. Effect of styrene concentration on the size of microspheres is studied using DLS and optical microscopy. Finally, the role of AuNP-SOMs as efficient photocatalyst is established through several control experiments and a reaction pathway is proposed.
PREPARATION OF POLYSTYRENE SEEDS AND PETAL-LIKE COMPOSITE POLYMER PARTICLES
PSt种子与“花瓣”形PSt/PAN复合颗粒的制备

WANG Hongyan,NI Zhongbin,YANG Cheng,LIU Xiaoya,CHEN Mingqing,
王红艳
,倪忠斌,杨成,刘晓亚,陈明清

高分子学报 , 2007,
Abstract: The monodisperse submicron-size polystyrene(PSt) microspheres were prepared by emulsifier-free emulsion polymerization of styrene(St) using potassium persulfate(KPS) as initiator in ethanol-water mixed solvents.The effects of the concentration of KPS and St,polymerization temperature and the composition of the solvent on the size and morphology of PSt microspheres were investigated by scanning electron microscopy(SEM).The results indicate that the above factors evidently affect the diameter of the microspheres.The petal-like composite polymer particles were produced by emulsifier-free seeded emulsion polymerization in the presence of PSt seeds,styrene and acrylonitrile(AN) monomers using poly(ethylene glycol)(PEG) which has a methacryloyl group in the polymer end as reaction stabilizer.Such nonspherical shapes were controllable by change the ratio of St to AN.Such a surface morphology may provide a valuable information to elucidate the formation mechanism of the petal-like particles prepared by emulsifier-free seeded emulsion polymerization in the presence of PEG macromonomers.The result ulteriorly proved the formation mechanism of the unusual morphology for dispersion copolymerization system.
Preparation of monodisperse, superparamagnetic, luminescent, and multifunctional PGMA microspheres with amino-groups
WeiCai Wang,Qi Zhang,BingBo Zhang,DeNa Li,XiaoQing Dong,Lei Zhang,Jin Chang
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-007-0512-6
Abstract: Micron-sized, monodisperse, superparamagnetic, luminescent composite poly(glycidyl methacrylate) (PGMA) microspheres with functional amino-groups were successfully synthesized in this study. The process of preparation was as follows: preparation of monodisperse poly(glycidyl methacrylate) microspheres by dispersion polymerization method; modification of poly(glycidyl methacrylate) microspheres with ethylene diamine to form amino-groups; impregnation of iron ions (Fe2+ and Fe3+) inside the microspheres and subsequently precipitating them with ammonium hydroxide to form magnetite (Fe3O4) nanoparticles within the polymer microspheres; infusion of CdSe/CdS core-shell quantum dots (QDs) into magnetic polymer microspheres. Scanning electron microscopy (SEM) was used to characterize surface morphology and size distribution of composite microspheres. The average size of microspheres was 1.42 μm with a size variation of 3.8%. The composite microspheres were bright enough and easily observed using a conventional fluorescence microscope. The composite microspheres were easily separated from solution by magnetic decantation using a permanent magnet. The new multifunctional composite microspheres are promising to be used in a variety of bioanalytical assays involving luminescence detection and magnetic separation.
Preparation of monodisperse, superparamagnetic, luminescent, and multifunctional PGMA microspheres with amino-groups
WANG WeiCai,ZHANG Qi,ZHANG BingBo,LI DeNa,DONG XiaoQing,ZHANG Lei,CHANG Jin,

科学通报(英文版) , 2008,
Abstract: Micron-sized, monodisperse, superparamagnetic, luminescent composite poly(glycidyl methacrylate) (PGMA) microspheres with functional amino-groups were successfully synthesized in this study. The process of preparation was as follows: preparation of monodisperse poly(glycidyl methacrylate) microspheres by dispersion polymerization method; modification of poly(glycidyl methacrylate) microspheres with ethylene diamine to form amino-groups; impregnation of iron ions (Fe2+ and Fe3+) inside the microspheres and subsequently precipitating them with ammonium hydroxide to form magnetite (Fe3O4) nanoparticles within the polymer microspheres; infusion of CdSe/CdS core-shell quantum dots (QDs) into magnetic polymer microspheres. Scanning electron microscopy (SEM) was used to characterize surface morphology and size distribution of composite microspheres. The average size of microspheres was 1.42 μm with a size variation of 3.8%. The composite microspheres were bright enough and easily observed using a conventional fluorescence microscope. The composite microspheres were easily separated from solution by magnetic decantation using a permanent magnet. The new multifunctional composite microspheres are promising to be used in a variety of bioanalytical assays involving luminescence detection and magnetic separation. Supported by the National Natural Science Foundation of China (Grant No. 50373033)
分散聚合制备聚苯乙烯微球及影响因素研究
Preparation and Effects of Polystyrene Microspheres by Dispersion Polymerization
 [PDF]

周珑, 戴金辉, 展飞
Material Sciences (MS) , 2013, DOI: 10.12677/MS.2013.31008
Abstract:
以聚乙烯吡咯烷酮为分散剂,水及无水乙醇为反应介质,偶氮二异丁腈引发剂,采用分散聚合的方法,制备出了一系列亚微米级的PS微球,分析了单体、引发剂、分散剂的用量,反应介质组成和搅拌速度对产物粒径及粒径分布的影响。结果表明,利用分散聚合,初步实现了PS粒径的可控,反应物组成对微球粒径及分布起主要作用,而搅拌速率只对微球粒径有影响,对粒径分布影响不大。
Polystyrene microspheres sized in sub micron were prepared by a dispersion polymerization with PVP as dispersant, H2O and ethanol as reaction medium, AIBN as initiator. The effects of H2O-ethanol ratio, string speed and amount of styrene, AIBN and PVP on particle size and distribution were discussed. Results show that PS spheres size could be preliminarily control. The component of reactant is the main effect of size and distribution, meanwhile, spin rate only effects sphere size.
PBA HOLLOW MICROSPHERES PREPARED THROUGH ULTRASONICALLY INITIATED ENCAPSULATION EMULSION POLYMERIZATION
超声辐照乳液聚合制备聚丙烯酸正丁酯空心微球

GUO Shengwei,WANG Qi,ZHAO Yue,
郭生伟
,王琪,赵越

高分子学报 , 2009,
Abstract: An efficient,clean and simple preparation method of polymer hollow microspheres was provided.Ultrasonic irradiation was applied to prepare hollow polymer microspheres,which provided multi-functions of intensive dispersion,agitation,emulsification and initiation.As a result,poly(butyl acrylate)(PBA)hollow microspheres were prepared by ultrasonically initiated encapsulation emulsion polymerization.The structure and size distribution of the obtained products were investigated by transmission electron microscop...
Mathematical modeling of polystyrene particle size distribution produced by suspension polymerization
Machado, R.A.F.;Pinto, J.C.;Araújo, P.H.H.;Bolzan, A.;
Brazilian Journal of Chemical Engineering , 2000, DOI: 10.1590/S0104-66322000000400004
Abstract: particle size distribution (psd) of polystyrene particles produced by suspension polymerization is of fundamental importance in determining suspension stability and product quality attributes. within a population balance framework, a model is proposed for suspension polymerization reactors to describe the evolution of the psd. the model includes description of breakage and coalescence rates in terms of reaction kinetics and rheology of the dispersed phase. the model is validated with experimental data of styrene suspension polymerization.
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