Monodisperse glycidyl-functional polymer particles in the micron-size range by seeded polymerization

Polymer particles having glycidyl ether groups were prepared through seeded polymerization in aqueous medium. The polystyrene seed particles were swollen with a mixture of n-butyl methacrylate, glycidyl methacrylate, ethylene glycol dimethacrylate, and benzoyl peroxide initiator. The particles produced after polymerization were characterized regarding the particle morphology and functionality. Optical microscopy and scanning electron microscopy showed that the particles are in the size range of 13–14 μm and are highly monodisperse with heterophase structures. Actually, the high content of glycidyl methacrylate in the second monomer mixture caused the particle phase to be homogeneous. This effect was explained in terms of the surface tension of each polymer phase. Moreover, the cross-linking of the seed particles had a significant effect on the final particle morphology. From the HCl–dioxane back titration method, it was found that about 20–30% of glycidyl ether groups still remained on the final particles. Received: 25 February 2000 Accepted: 10 November 2000     

Preparation of micron-sized monodispersed highly monomer- “adsorbed” polymer particles having snow-man shape by utilizing the dynamic swelling method with tightly cross- linked seed particles

Micron-sized, monodispersed highly styrene-“adsorbed” particles having snow-man shape were prepared by the dynamic swelling method (DSM) with tightly cross-linked polymer seed particles as follows. First, 3.8 μm-sized monodispersed polystyrene (PS)/ poly(divinylbenzene) (PDVB) (PS/PDVB = 1/10 wt. ratio) composite particles produced by seeded polymerization utilizing DSM were dispersed in an ethanol/water (6/4, w/w) solution dissolving styrene monomer, and poly(vinyl alcohol) as a stabilizer. Second, water was subsequently added to the dispersion with a micro-feeder at a rate of 2.88 ml/h at room temperature. The cross-linked seed particles adsorbed a large amount of styrene onto the surfaces and resulted in mono-dispersed highly styrene-“adsorbed” snow-man shape particles having about 10 μm in diameter. Received: 16 April 1998 Accepted: 9 June 1998     

Bioligand carriers based on methyl methacrylate copolymers with <Emphasis Type="Italic">N</Emphasis>-vinylformamide or glycidyl methacrylate

Emulsifier-free emulsion copolymerization of methyl methacrylate with N-vinylformamide and glycidyl methacrylate initiated by a cationic or anionic azoinitiator in the presence of dextran is used to produce monodisperse polymer particles with a developed multifunctional surface. As a result, monodisperse particles are obtained with a diameter of 350–660 nm, the surface layer of which contains, in addition to carboxyl groups, amino or epoxy groups. The conditions are determined for the formation of multifunctional hydrophilic particle surface via the hydrolysis of comonomer units and residual groups of initiators. The limiting values of bovine serum albumin chemisorption (2.4 and 1.0 mg/m² on the particles of methyl methacrylate copolymers with glycidyl methacrylate or N-vinyl formamide, respectively) indicate that the obtained particles have sufficient sorption capacity to be applied as carriers for immunoreagents.     

Preparation of micron-size monodisperse polymer particles having highly crosslinked structures and vinyl groups by seeded polymerization of divinylbenzene using the dynamic swelling method

Micron-size monodisperse polystyrene/polydivinylbenzene (PS/PDVB) composite particles having highly crosslinked structures and vinyl groups were prepared as follows. First, 1.9 m-size monodisperse PS seed particles produced by dispersion polymerization were dispersed in ethanol/water (70/30, w/w) solution which dissolved divinylbenzene (DVB) monomer, benzoyl peroxide as an initiator and poly(vinyl alcohol) as a stabilizer. The PS seed particles were swollen with a large amount of DVB monomers to 4.3 m in diameter while keeping good monodispersity by the dynamic swelling method, where water was slowly added, continuously, with a micro feeder into the dispersion. And then, the seeded polymerization of the absorbed DVB was carried out.Part CXXXV of the series Studies on Suspension and Emulsion     

Influence of the kind of end groups of polysterene on the production of hollow particles by suspension polymerization for divinylbenzene/toluene droplets dissolving them

Suspension polymerizations for divinylbenzene (DVB)/ toluene droplets dissolving polystyrene (PS) having different end groups were carried out. Hollow polymer particles were not obtained with PS having polar sulfate end groups, which were prepared by emulsifier-free emulsion polymerization with potassium persulfate initiator. On the other hand, they were obtained with PS having low polarity isobutyronitrile end groups, which were prepared by solution polymerization with 2,2′-azobis(isobutyronitrile) initiator. The interfacial tensions between the water and xylene/toluene (1/1, w/w) mixture solution of PS having polar groups was smaller than that having low polarity groups. From these results, it is concluded that the preferential adsorption of PDVB molecules formed by the suspension polymerization at the interface of the droplets over PS molecules, which depended on the kind of the end groups, is one of the key factors for the formation of the hollow structure. Received: 5 September 2000 Accepted: 13 December 2000     

Production of micron-sized, monodisperse, transformable rugby-ball-like-shaped polymer particles

Micron-sized, monodisperse, “rugby-ball-like” polymer particles were produced by seeded polymerization for the dispersion of (divinylbenzene/vinylbiphenyl/xylene)-swollen polystyrene particles prepared by utilizing the dynamic swelling method which the authors proposed in 1991. The shape of the composite polymer particle was reversibly transformed between a rugby-ball-like shape and a spherical one by absorbing/releasing toluene. Received: 24 January 2001/Accepted: 18 April 2001     

Production of hollow polymer particles by suspension polymerization

 Polymer particles having single hollow in the inside were successfully prepared by suspension polymerization for divinylbenzene/ toluene droplets dissolving polystyrene (PS) in an aqueous solution of poly(vinyl alcohol). Such a hollow polymer particle was not obtained without PS. The hollow structure was affected by the molecular weight and the concentration of PS. Received: 3 December 1997 Accepted: 27 March 1998     

Surface modification of monodisperse hydroxyl functionalized polymeric microspheres using ceric ammonium nitrate

The surface modification of monodisperse hydroxyl functionalized polymeric microspheres was carried out by utilizing a redox initiation system. Styrene, divinylbenzene and hydroxyethyl methacrylate were used as the second monomer in the seeded polymerization. An excessive amount of the second monomer emulsion was swollen into the polystyrene (PS) seed particles completely by controlling the medium solvency and swelling temperature. The hydroxyl functional groups were radicalized by the ceric ammonium nitrate in nitric acid solution, and the methyl methacrylate was reacted uniformly on the surface of microspheres. From the SEM, and FE-TEM measurements, highly monodisperse microspheres having a smooth surface, and polymethylmethacrylate (PMMA) coating layer were observed, respectively. The surface characteristics of the PS seed particles, hydroxyl functionalized and surface-modified polymeric microspheres were confirmed by utilizing FT-IR, XPS and thermal analysis.     

Influence of particle diameter on the morphology of micron-sized, monodispersed composite polymer particles produced by seeded polymerization for the dispersion of highly monomer-swollen polymer particles

 Micron-sized, monodispersed polystyrene (PS)/poly (n-butyl methacrylate) (PBMA) composite particles, in which the PS domain(s) were dispersed in a PBMA continuous phase, were produced by seeded polymerization for dispersions of n-butyl methacrylate (BMA) swollen PS particles in a wide range of PS/BMA ratios in the presence of NaNO₂ as a water-soluble inhibitor. Moreover, in order to change the diameter of the composite particles at same PS/BMA ratio, PS/PBMA (1/150 w/w) composite particles were produced using five kinds of PS particles in a range of diameters from 0.64 to 3.27 μm as seeds. The percentages of the PS/PBMA composite particles having double and triple and over PS domains, which were thermodynamically unstable morphologies, increased with the increase in the diameter of BMA swollen PS particles. There was a clear influence of the size of the swollen particles on the morphology of the PS/PBMA composite particles produced. Received: 30 September 1999/Accepted: 18 April 2000     

Hydrobromination of residual vinyl groups on divinylbenzene polymer particles followed by atom transfer radical surface graft polymerization

Rigid and monodisperse spherical polymer particles with 2.36 ± 0.18 μm diameter containing residual surface vinyl groups were prepared by photoinitiated precipitation polymerization of divinylbenzene. Anti‐Markovnikov addition of HBr to the surface vinyl groups yielded a 2‐bromoethyl functionality that was used as macroinitiator for atom transfer radical polymerization (ATRP), providing the possibility for further functionalization by controlled “grafting from” processes. This was demonstrated by grafting of glycidyl methacrylate brushes from the particle surface, using an ATRP system based on CuBr and pentamethyl diethylenetriamine. Existence of a methacrylic overlayer was verified by FTIR and XPS measurements, and the grafted particles were easily dispersed in water, confirming conversion of the particle surface from hydrophobic to hydrophilic. Hydrobromination of residual vinyl groups yields a macroinitiator that can be used for grafting of glycidyl methacrylate by ATRP. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1259–1265, 2009     

Adsorption of styrene on micron-sized, monodisperse, cross-linked polymer particles in a snowman-shaped state by utilizing the dynamic swelling method

Polystyrene/styrene–divinylbenzene copolymer composite particles with different cross-linking densities were produced by seeded copolymerization for (styrene/divinylbenzene)-swollen polystyrene particles prepared by utilizing the dynamic swelling method (DSM) which was proposed by the authors in 1991. Using the cross-linked, composite particles as seeds, styrene-adsorbed (swollen) composite particles having snowman shapes were prepared by the DSM. With a decrease in the cross-linking density in the composite particles, the volume of the composite particle which was embedded in a spherical styrene phase in the snowman-shaped, styrene-adsorbed particle increased and the contact angle of the styrene phase on the composite particle decreased. In the DSM process, the absorption stage of styrene in the composite particles and the adsorption stage thereon were clearly observed. This suggests that the cross-linking density of the composite particles greatly affects the morphology of the snowman-shaped particles. Received: 13 December 2000 Accepted: 14 March 2001     

Synthesis and characterization of epoxy-functional polystyrene particles

Colloidal polystyrene particles with surface epoxy groups have been synthesized through surfactant-free emulsion copolymerization of styrene with glycidyl methacrylate; and through copolymerization of glycidyl methacrylate (GMA) and methyl methacrylate as shells around existing polystyrene seed particles. We developed two titration methods to quantify the number of epoxy groups that survived the polymerization processes. The styrene-GMA copolymer particles were judged to be unsatisfactory as model colloidal materials due to their size polydispersity and unknown internal distribution of epoxy groups. The core-shell particles had high epoxy surface densities with at least 60% of the initial epoxy groups surviving the synthesis process. Transmission electron microscopy shows that the thickness of the epoxy-rich shell is less than expected based on the volume of monomers added, suggesting that some of the monomer forms water-soluble oligomers. Photon correlation spectroscopy measurements imply that the shell is swollen with water and consists of polymer configurations which extend out into solution. The morphological details vary consistently with the GMA content, and hence the hydrophilicity, of the shell polymer. © 1995 John Wiley & Sons, Inc.     

Influence of viscosity within polymerizing particle on the morphology of micron-sized,monodisperse composite polymer particles produced by seeded polymerization for the dispersion of highly monomer-swollen polymer particles

Micron-sized, monodisperse polystyrene (PS)/poly( n-butyl methacrylate) (PBMA) composite particles, in which PS domain(s) were dispersed in a PBMA continuous phase, were produced by seeded polymerization for the dispersion of highly n-butyl methacrylate (BMA)-swollen PS particles (PS/BMA=1/150, w/w) using various concentrations of benzoyl peroxide as initiator in the absence/presence of sodium nitrite (NaNO ₂) as a water-soluble inhibitor. The percentages of the composite particles having double, triple and over PS domains, which were thermodynamically unstable morphologies, increased with a rapid increase of viscosity within the polymerizing particle.     

Preparation of Composite Polymer Particles by Seeded Dispersion Polymerization in Ionic Liquids

Summary: Submicron-sized monodisperse PS particles were prepared by dispersion polymerization of styrene in ionic liquids with poly(vinylpyrrolidone) as stabilizer. Seeded dispersion polymerization of MMA was subsequently carried out with PS seeds in [Bmim][BF₄] to prepare PS/PMMA composite particles. Observation of the obtained particles of ultrathin cross-sections with a scanning and transmission electron microscope revealed that no secondary nucleation occurred during the seeded dispersion polymerization and that the particles have a core-shell morphology consisting of a PS core and a PMMA shell. Successful preparation of PS/PMMA composite particles in an ionic liquid has thus been demonstrated. Moreover, PS/PAA (PS-core/PAA-shell) composite particles were prepared by seeded dispersion polymerization in [DEME][TFSI], illustrating that hydrophobic/hydrophilic composite particles can be readily prepared in the ionic liquid.     

Morphology of micron-sized monodispersed composite polymer particles produced by seeded polymerization for the dispersion of highly monomer-swollen polymer particles

 Monodispersed polystyrene (PS)/poly(n-butyl methacrylate) (PBMA) composite particles having 9.4 μm in diameter were produced by seeded polymerization for the dispersion of highly n-butyl methacrylate (BMA)-swollen PS particles, and their morphologies were examined. The highly BMA-swollen PS particles (about 150 times the weight of the PS seed particles) were prepared by mixing monodispersed 1.8 μm-sized PS seed particles and 0.7 μm sized BMA droplets prepared with an ultrasonic homogenizer in ethanol/water (1/2, w/w) medium at room temperature. After NaNO₂ aqueous solution as inhibitor was added in the dispersion, the seeded polymerization was carried out at 70 °C. In an optical microscopic observation, one or two spherical high contrast regions which consisted mainly of PS were observed inside PS/PBMA composite particles. In the PS domain, there were many fine spherical PBMA domains. Such morphologies were based on the phase separation of PS and PBMA within the homogeneous swollen particles during the seeded polymerization. Received: 04 June 1997 Accepted: 27 August 1997     

Influence of the swelling state of seed polymer particles with monomer on the morphology of micron-sized monodispersed composite polymer particles produced by seeded polymerization utilizing the dynamic swelling method

 Micron-sized mono-dispersed polystyrene (PS)/poly(n-butyl methacrylate) (PBMA) composite particles (PS/PBMA=2/1 by weight) having a heterogeneous structure in which many fine PBMA domains dispersed in a PS matrix near the particle surface were produced by seeded polymerization of n-butyl methacrylate (BMA) of which almost all had been absorbed by 1.8 μm-sized monodispersed PS seed particles utilizing the dynamic swelling method. The morphology was varied by changing the PS/BMA ratio and polymerization temperature. It was concluded that the swelling state of 2 μm-sized BMA-swollen PS particles in the seeded polymerization process is one of the important factors to control the morphology of the composite particles. Received: 27 November 1996 Accepted: 21 March 1997     

A cation-exchange material for protein separations based on grafting of thiol-terminated sulfopropyl methacrylate telomers onto hydrophilized monodisperse divinylbenzene particles

A strong cation-exchange separation material has been prepared from monodisperse divinylbenzene particles modified by a "grafting to" approach, utilizing as anchoring points epoxy groups introduced onto the surface of the particles via oxidation of residual vinyl groups. The grafted chains consisted of thiol-terminated telomers of sulfopropyl methacrylate prepared by iniferter mediated polymerization, and grafting was performed by reaction of the corresponding thiolate anion with the surface epoxy groups. Attachment through epoxy moieties that were subsequently converted into 2,3-propanediol groups increased the hydrophilicity of the polymeric particles and incubation experiments showed no signs of the proteins denaturing on the column during an extended contact time of 1 h at room temperature. The performance of the grafted material was demonstrated by the chromatographic separation of cytochrome C, lysozyme, myoglobin, and ribonuclease A, in a cation-exchange mode.     

Poly(N-vinylcaprolactam-co-glycidyl methacrylate) aqueous microgels labeled with fluorescent LaF3:Eu nanoparticles

We describe the synthesis and properties of functional microgel particles based on poly(N-vinylcaprolactam-co-glycidyl methacrylate) (PVCL/PGMA) copolymer. A series of colloidally stable microgel particles with a range of glycidyl methacrylate content were prepared by surfactant-free heterophase polymerization in water. The microgel particles obtained had hydrodynamic radii between 250 and 350 nm and were fairly monodisperse in size; however, a broadening of the particle size distribution was observed for samples with a low GMA content. The PVCL/PGMA microgel particles exhibit thermally responsive reversible changes in diameter in water, and the swelling degree increased with the PVCL fraction in the copolymer structure. These microgels were then modified with photoluminescent europium-doped lanthanum fluoride nanoparticles (LaF3:Eu-AEP) through reaction of the 2-aminoethyl phosphate surface ligands with epoxy groups present in the microgel. These hybrid microgels were colloidally stable and thermally responsive in aqueous solution.     

Understanding and preventing the formation of deformed polymer particles during synthesis by a seeded polymerization method

Uniformly sized porous polymer particles with different polarity namely poly(divinylbenzene), poly(vinyl acetate‐co‐divinylbenzene), poly(ethylene dimethacrylate), and poly (glycidyl methacrylate‐co‐ethylene dimethacrylate) were prepared in the micron‐size range by a seeded polymerization method. Parameters affecting the particle morphologies including monomer mixture content, porogen content, and polystyrene (PS) seed latexes were varied, and the morphologies of the resulting particles were investigated by scanning electron and confocal microscopy. The results obtained indicated that the particle shape depended dominantly on the molecular weight of the PS seed template. Deformed particles, including collapsed spheres and spheres with holes were obtained when high molecular weight PS seeds were used, whereas well‐defined polymer particles were produced easily by using low molecular weight seeds. The use of 1,1‐diphenylethylene as a chain terminator during seed polymerization is proposed in this work as an efficient method to lower molecular weight of PS in seed particles while keeping seed size small. This low molecular weight seed template retained its spherical geometry after swelling and polymerization with different second stage monomers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Morphologies of micron-sized monodispersed composite polymer particles having crosslinked structures produced by seeded polymerizations

Three kinds of micron-sized monodispersed polystyrene (PS)/ poly(styrene - divinylbenzene) composite particles were produced by two kinds of seeded copolymerizations of styrene (S) and divinylbenzene (DVB) (PS seed/ (S+DVB)=2/1, wt. ratio; S/DVB=1/1, molar ratio) in the presence of about 2 μm-sized monodispersed PS particles, and their morphologies were examined. One was produced by a seeded dispersion copolymerization where almost monomers and initiators exist in an ethanol/water (12.6/4.0, w/w) medium. The others two were produced by seeded copolymerizations with the dynamic swelling method where almost monomers exist in the monomer-swollen particles using 2, 2'-azobisisobutyronitrile in monomer-swollen PS seed particles or using 4, 4'-azobis (4-cyanopentanoic acid) in an ethanol/water (7/43, w/w) medium. In the former polymerization, the produced composite particles had a high dense crosslinked shell, whereas in the latter two polymerizations, they did the comparatively homogeneous crosslinked structures.