Synthesis of the raspberry‐like PS/PAN particles with anisotropic properties via seeded emulsion polymerization initiated by γ‐ray radiation

We herein report a facile method to prepare the submicron‐sized raspberry‐like polystyrene/polyacrylonitrile particles with anisotropic properties and controllable structure via γ‐radiation‐induced seeded emulsion polymerization under ambient pressure and at room temperature, in which the monodisperse crosslinked styrene‐divinylbenzene‐acrylic acid terpolymer (P(S‐DVB‐AA)) particles were used as seed particles and acrylonitrile (AN) as the second monomer. The influence of the weight ratio of polymer/monomer, the absorbed dose rate, the absorbed dose, and the dispersion medium on the morphology of the as‐prepared particles was investigated. The final products were thoroughly characterized by Fourier transform infrared spectroscopy (FTIR), field‐emission scanning electron microscopy, and transmission electron microscopy. The results showed that the raspberry‐like particles could be fabricated in high yield. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis of polymeric core–shell particles using surface‐initiated living free‐radical polymerization

An easy and novel approach to the synthesis of functionalized nanostructured polymeric particles is reported. The surfactant‐free emulsion polymerization of methyl methacrylate in the presence of the crosslinking reagent 2‐ethyl‐2‐(hydroxy methyl)‐1,3‐propanediol trimethacrylate was used to in situ crosslink colloid micelles to produce stable, crosslinked polymeric particles (diameter size ～ 100–300 nm). A functionalized methacrylate monomer, 2‐methacryloxyethyl‐2′‐bromoisobutyrate, containing a dormant atom transfer radical polymerization (ATRP) living free‐radical initiator, which is termed an inimer (initiator/monomer), was added to the solution during the polymerization to functionalize the surface of the particles with ATRP initiator groups. The surface‐initiated ATRP of different monomers was then carried out to produce core–shell‐type polymeric nanostructures. This versatile technique can be easily employed for the design of a wide variety of polymeric shells surrounding a crosslinked core while keeping good control over the sizes of the nanostructures. The particles were characterized with scanning electron microscopy, transmission electron microscopy, optical microscopy, dynamic light scattering, and Raman spectroscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1575–1584, 2007     

Synthesis and characterization of micrometer‐sized particles of narrow size distribution with chloromethyl functionality on the basis of single‐step swelling of uniform polystyrene template microspheres

Polystyrene template microspheres of 1.4 ± 0.1 μm were prepared by dispersion polymerization of styrene in a mixture of ethanol and 2‐methoxy ethanol. These template particles were then swelled at room temperature in a single step with emulsion that was prepared in sodium dodecyl sulfate aqueous solution from a swelling solvent (dibutyl phthalate) containing the initiator (benzoyl peroxide) and monomer(s) (chlormethylstyrene, divinylbenzene, or ethylene dimethacrylate). Composite uniform particles composed of the template polystyrene and noncrosslinked or crosslinked polychloromethylstyrene were prepared by polymerizing the monomer(s) within the swelled particles at 73 °C. Crosslinked uniform polychloromethylstyrene particles of higher surface area were formed by dissolving the template polystyrene polymer of the composite particles. The influence of various reaction parameters, such as dibuthyl phthalate concentration, chloromethylstyrene concentration, crosslinker type and concentration, and so forth on the molecular weight, size, size distribution, shape, morphology, surface area, and decomposition temperature of the particles was investigated. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1342–1352, 2002     

Nonaqueous dispersion polymerization of styrene in methanol with the ionomer block copolymer poly[(4‐methylstyrene)‐co‐(4‐vinyltriethylbenzyl ammonium bromide)]‐b‐polyisobutene as a stabilizer

The nonaqueous dispersion polymerization of styrene in methanol with poly[(4‐methylstyrene)‐co‐(4‐vinyltriethylbenzyl ammonium bromide)]‐b‐polyisobutene as a stabilizer was investigated. There was no observable inducing period or autoacceleration in the polymerization process. The conversion increased almost linearly with the polymerization time as high as 80%. The average sizes of the obtained polystyrene particles increased, and the size distributions of the polystyrene particles tended to become narrower, with increasing conversion. The mechanism of the dispersion polymerization in the presence of polyisobutene‐b‐poly[(4‐methylstyrene)‐co‐(4‐vinyltriethylbenzyl ammonium bromide)] was nucleation/growth. When the stabilizer/monomer ratio (w/w) was greater than 2.0%, the polystyrene dispersion was stable, and there was no observable polymer particle coagulation taking place during the whole polymerization process. The average diameter of the polymer particles can be mediated through changes in the polymerization conversion, monomer, and stabilizer. Nearly monodispersed polystyrene particles with average diameters of approximately 0.45–2.21 μm were obtained under optimal conditions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2678–2685, 2004     

A Useful Poly(ethylene oxide)‐poly(propylene oxide)‐poly(ethylene oxide) Triblock Crosslinker in a Diffusion‐Controlled Polymerization Method

Monodisperse micron‐sized polystyrene particles crosslinked with a novel poly(ethylene oxide)‐poly(propylene oxide)‐poly(ethylene oxide) triblock diol diacrylate (t‐BDDA) were produced via simple dispersion polymerization. It was established that the monomer‐diffusible surface characteristics of primary particles played a decisive role in producing the monodisperse crosslinked polymer particles. We named this concept a diffusion‐controlled polymerization method, DPM. Here in this study, particularly, t‐BDDA is proposed as a very useful crosslinker capable of self‐assembling and crosslinking in the process of particle formation and particle growth.     

Use of a new methacrylic monomer, 4,4′‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)benzophenone,in the synthesis of porous microspheres

A new aromatic, tetrafunctional methacrylate monomer, 4,4′‐di(2‐hydroxy‐3‐methacryloyloxypropoxy)benzophenone, and its application to the synthesis of porous microspheres are presented. This new monomer was copolymerized with divinylbenzene in the presence of pore‐forming diluents. The properties of the obtained highly crosslinked microspheres were investigated as column packing for high‐performance liquid chromatography. Their porous structures in both dry and wet states were studied and compared with those of poly(divinylbenzene) and the less crosslinked copolymer of 2,3‐epoxypropyl methacrylate and divinylbenzene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 7014–7026, 2006     

Modification of porous suspension‐PVC particles by stabilizer‐free aqueous dispersion polymerization of absorbed acrylate monomers

The present study describes modification of porous PVC particles by polymerization of a monomer/crosslinker/peroxide solution absorbed within the PVC particles. The modifying crosslinked polymers include butyl acrylate (BA) crosslinked with ethylene glycol dimethacrylate (EGDMA) and ethylhexyl acrylate (EHA) crosslinked with EGDMA. The monomer solution is blended with the PVC particles by dry‐blending. The monomer absorbed particles are then polymerized in a stabilizer‐free aqueous dispersion‐polymerization. The modified semi‐IPN PVC particles have better stability than the neat PVC particles in packed columns for absorption of halo‐organics from water, etc. The modified semi‐IPN PVC particles are melt processable and thus have the potential of being interesting and useful modified rigid PVC materials. The modified PVC particles characterization includes polymerization yield, non‐extractables and porosity measurements and also morphology and dynamic mechanical behavior (DMTA). PBA and PEHA polymerization has shown high yield levels. The high conversion of BA and EHA within the particle, is partly due to their low solubility in water. The levels of non‐extractable fractions found are indicative of low chemical interaction between the polyacrylate/PVC phases in the particle. The modified PVC particle's porosity levels indicate that BA and EHA partly polymerize within the PVC particles' bulk and partly in the pores as crusts covering the PVC pore surfaces. This finding is supported by SEM observations of unetched and etched freeze fractured surfaces. Higher crosslinking levels of the polyacrylate modification promote compatibility with the PVC particles' bulk. DMTA measurements show two loss modulus peaks for the 0.5%EGDMA blends in the glass transition temperature region, suggesting imcompatibility. However, at 5%EGDMA a single transition is found exhibiting enhanced compatibility owing to the high degree of crosslinking, which prevents phase separation. Copyright © 2002 John Wiley & Sons, Ltd.     

Fully crosslinked poly(styrene‐co‐divinylbenzene) microspheres by precipitation polymerization and their superior thermal properties

Fully crosslinked, stable poly(styrene‐co‐divinylbenzene) microspheres, which are composed of various concentrations of divilylbenzene from 5 to 75 mol % based on styrene monomer, were prepared without a significant particle coagulation by the precipitation polymerization. The number‐average particle diameter ranged from 3.5 to 2.8 μm and decreased with an increasing concentration of divinylbenzene in monomer. In addition, the coefficient of variation of the microspheres was slightly reduced with the increasing concentration of divinylbenzene. The circularity and the measured specific surface area indicated that lesser particles are coagulated because of the improved stability of individual particles at a high divinylbenzene concentration and that the resulting particles have a smooth surface without micropores. The glass‐transition temperature was not observed for all microspheres formed from the range of divinylbenzene concentrations. In addition, the onset of the thermal‐degradation temperature was increased from 339.8 to 376.9 °C upon higher contents of divinylbenzene. On the basis of the DSC and thermogravimetric data, the polymer microspheres prepared by the precipitation polymerization possessed a fully crosslinked structure and highly enhanced thermal stability. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 835–845, 2004     

Poly(2‐hydroxyethyl methacrylate‐co‐N,O‐dimethacryloylhydroxylamine) particles by dispersion polymerization

Poly(2‐hydroxyethyl methacrylate‐co‐N,O‐dimethacryloylhydroxylamine) particles were prepared by dispersion polymerization in toluene/2‐methylpropan‐1‐ol medium using cellulose acetate butyrate and dibenzoyl peroxide (BPO) as a steric stabilizer and initiator, respectively. The particle size was reduced with decreasing solvency of the reaction medium (more nuclei were generated) because the critical chain length of the precipitated oligomers decreased with an increasing toluene content, which is a poorer solvent for the polymer than 2‐methylpropan‐1‐ol. There is an optimum initiator concentration (2 wt % BPO relative to monomers) for producing low‐polydispersity particles under given conditions. Additionally, discrete spherical particles were obtained at a low monomer concentration and/or higher polymerization temperature. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1625–1632, 2002     

Synthesis of crosslinked poly(butyl methacrylate‐co‐pentaerythritol triacrylate) gel by single electron transfer‐living radical polymerization and its oil‐absorbing properties

A novel high oil‐absorbing crosslinked gel was synthesized by copolymerization of butyl methacrylate (BMA) with a small amount of pentaerythritol triacrylate (PETA) crosslinker using single electron transfer‐living radical polymerization (SET–LRP) initiated with carbon tetrachloride (CCl₄) and catalyzed by Cu(0)/hexamethylenetetramine (HMTA) in N, N‐dimethylformamide (DMF). The polymerization followed first‐order kinetics as indicated by linear increase of monomer concentration with reaction time. Effects of reaction temperature, crosslinker, initiator, and catalyst on the oil‐absorbing properties of the crosslinked gel were investigated in detail. The oil absorptions of the crosslinked gel to chloroform, toluene could reach 51.9, 34.5 g/g, respectively. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and characterization of dual‐responsive micrometer‐sized core‐shell composite polymer particles

Dual‐responsive micrometer‐sized core‐shell composite polymer particles were prepared by dispersion polymerization followed by seeded copolymerization. Polystyrene (PS) particles prepared by dispersion polymerization were used as core particles. N‐isopropyl acrylamide (NIPAM) and methacrylic acid (MAA) were used to induce dual‐responsive that is thermo‐ and pH‐responsive properties in the shell layer of composite polymer particles, prepared by seeded copolymerization with PS core particles. Temperature‐ and pH‐dependent adsorption behaviors of some macromolecules on composite polymer particles indicate that produced composite polymer particles exhibit dual‐responsive surface properties. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis and characterization of spherical and hemispherical polyepoxide micrometer‐sized particles of narrow size distribution by a single‐step swelling of uniform polystyrene template microspheres with glycidyl methacrylate

Polystyrene template microspheres of narrow size distribution were prepared by dispersion polymerization of styrene in a mixture of ethanol and 2‐methoxy ethanol. Spherical and hemispherical polystyrene/poly(glycidyl methacrylate) microspheres of narrow size distribution were prepared by a single‐step swelling of the polystyrene template microspheres with the swelling solvent monomer glycidyl methacylate, followed by polymerization of the monomer within the swollen template microspheres at 73 °C. Uniform polystyrene/poly(glycidyl methacylate‐ethylene glycol dimethacrylate) polyepoxide composite microspheres were synthesized similarly, substituting glycidyl methacylate for glycidyl methacylate and ethylene glycol dimethacrylate. Uniform crosslinked poly(glycidyl methacylate‐ethylene glycol dimethacrylate) polyepoxide microspheres have been prepared by dissolution of the PS template polymer of the former composite microspheres. Particles with different properties, for example size, size distribution, shape, surface morphology, surface area, and so forth, were prepared by changing various parameters belonging to the swelling and/or polymerization steps, for example, volume of the swelling monomer/s and/or the swelling solvent dibutyl phthalate. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4612–4622, 2007     

Free‐radical crosslinking copolymerization of 2,2′‐azobis[N‐(2‐propenyl)‐2‐methylpropionamide] with vinyl benzoate resulting in polymeric azo initiators

2,2′‐Azobis[N‐(2‐propenyl)‐2‐methylpropionamide] (APMPA) with two carbon–carbon double bonds and an azo group was copolymerized with vinyl benzoate (VBz) at 60 °C, resulting in azo groups containing VBz/APMPA prepolymers and crosslinked polymers as soluble and insoluble polymeric azo initiators, respectively. The polymerization characteristics of APMPA as a novel diallyl monomer were clarified with the rate and degree of polymerization and the monomer reactivity ratios. The gelation behaviors in VBz/APMPA crosslinking copolymerizations were examined in detail with a comparison of the actual gel point and the theoretical gel point calculated according to Stockmayer's equation with the tentative assumption of equal reactivity for both vinyl groups belonging to VBz and APMPA. The effectiveness of the resulting branched or crosslinked poly(VBz‐co‐APMPA)s as soluble or insoluble polymeric azo initiators, respectively, at providing graft polymers through the cleavage of azo groups at an elevated temperature was examined by the polymerization of allyl benzoate at 120 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 317–325, 2002     

Gel forming waterborne dispersion polymerization of sodium p‐styrene sulfonate with glycidyl methacrylate

Water soluble monomer like sodium p‐styrene sulfonate (SSS) is copolymerized with hydrophobic and reactive monomer glycidyl methacrylate (GMA). The polymerization proceeds as dispersion and forms gels. The gel forming nature prevails even with other hydrophobic and hydrophilic monomers to form ternary polymeric systems. The swelling is dependent on polymer composition as well as the treatment history of polymers. SSS also induces ring opening of GMA to form 1,2‐diols as confirmed independently by various model reactions. The ability of hydrogels to absorb various dyes indicates that owing to the anionic nature, hydrogels absorb cationic dyes nearly quantitatively. Because of their strong affinity to cationic species these hydrogel forming polymers are potentially useful in water purification applications as well as purification of proteins. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 626–634     

Effects of the reaction parameters on the properties of thermosensitive poly(N‐isopropylacrylamide) microspheres prepared by precipitation and dispersion polymerization

Poly(N‐isopropylacrylamide) (PNIPAAm)‐based microspheres were prepared by precipitation and dispersion polymerization. The effects of several reaction parameters, such as the type and concentration of the crosslinker (N,N′‐methylenebisacrylamide or ethylene dimethacrylate), medium polarity, concentration of the monomer and initiator, and polymerization temperature, on the properties were examined. The hydrogel microspheres were characterized in terms of their chemical structure, size and size distribution, and morphological and temperature‐induced swelling properties. A decrease in the particle size was observed with increasing polarity of the reaction medium or increasing concentration of poly(N‐vinylpyrrolidone) as a stabilizer in the dispersion polymerization. The higher the content was of the crosslinking agent, the lower the swelling ratio was. Too much crosslinker gave unstable dispersions. Although the solvency of the precipitation polymerization mixture controlled the PNIPAAm microsphere size in the range of 0.2–1 μm, a micrometer range was obtained in the Shellvis 50 and Kraton G 1650 stabilized dispersion polymerizations of N‐isopropylacrylamide in toluene/heptane. Typically, the particles had fairly narrow size distributions. Copolymerization with the functional glycidyl methacrylate monomer afforded microspheres with reactive oxirane groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 968–982, 2006     

Synthesis and evaluations of bisphosphonate‐containing monomers for dental materials

Two new bismethacrylamide ( 1 , 2 ) and two new methacrylamide ( 3 , 4 ) dental monomers were synthesized. In each group, one monomer contains a bisphosphonate group, the other a bisphosphonic acid group. Monomer 1 and 3 were synthesized by amidation of 2‐(2‐chlorocarbonyl‐allyloxymethyl)‐acryloylchloride and methacryloyl chloride with tetraethyl aminomethyl‐bis(phosphonate) and converted to the bisphosphonic acid monomers 2 and 4 by hydrolysis with trimethylsilyl bromide. Monomer 1 (m.p.: 71–72 °C), monomer 3 ( 33–34 °C), and monomer 4 (no m.p.) were obtained as white solids and monomer 2 a viscous liquid, soluble in water. Homopolymerization of 1 gave crosslinked polymers, indicating its low cyclization tendency. The photopolymerization studies indicated that its copolymerizability with 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxy propyloxy) phenyl] propane and 2‐hydroxyethyl methacrylate (HEMA) without changing their rates and conversions significantly means that it could be used as a biocompatible crosslinker. Although monomer 2 showed low polymerizability, because of its good performance in terms of solubility, hydrolytic stability, hydroxyapatite interaction, acidity, and copolymerizability with HEMA, it shows potential to be used in self‐etching dental adhesives. The thermal polymerization of 3 resulted in soluble polymers and evaluation of monomer 4 in terms of solubility, acidity, and copolymerizability with HEMA indicated its potential as an adhesive monomer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and polymerizations of phosphonated‐bis(methacrylamide)s for dental applications

Novel phosphonate and phosphonic acid‐containing bis(methacrylamide)s were synthesized. The phosphonate‐containing monomers ( 1a and 1b ) were synthesized by amidation of 2‐(2‐chlorocarbonyl‐allyloxymethyl)‐acryloylchloride with diethyl 2‐aminoethylphosphonate and diethyl 1‐aminomethylphosphonate. The phosphonic acid‐containing monomers ( 2a and 2b ) were synthesized by hydrolysis of 1a and 1b with trimethylsilyl bromide (TMSBr). All monomers were liquids and dissolved in water and ethanol. Thermal homopolymerization of 1a and 1b in bulk and solution using 2,2′‐azobis(isobutyronitrile) (AIBN) at 80 °C gave crosslinked polymers indicating low cyclization tendencies of these monomers. They were also homopolymerized using photo‐DSC with 2,2′‐dimethoxy‐2‐phenyl acetophenone (DMPA) as photoinitator, and their maximum rates of polymerization were found to be higher than commercial monomers 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxy propyloxy) phenyl] propane (Bis‐GMA) and 2‐hydroxyethyl methacrylate (HEMA), indicating their potential as reactive diluents or crosslinkers in dental materials. In fact, copolymerization with monomer 1a resulted in improvements in photopolymerization kinetics of both Bis‐GMA and HEMA. The acidic nature of the aqueous solutions (pH of 2a : 1.42, 2b : 1.53), stability under aqueous conditions after 1 month of study at 37 °C, interaction of 2a with hydroxyapatite (HAP) as representative of both monomers, and copolymerizability of the same with HEMA make these monomers suitable as adhesive monomers in dental adhesives, although their low observed reactivities may present a drawback. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Polycarbonate particles and dye‐labeled particles by miniemulsion polymerization

We describe the synthesis of several different polycarbonate particles by miniemulsion polymerization. The monomers were allylmethyl carbonate (AlMeC), di(ethylene glycol) bisallylcarbonate (DBAC), and 4‐vinyl‐1,3‐dioxan‐2‐one [vinyl ethylene carbonate (VEC)]. For these polymerizations, higher monomer conversions were obtained with oil‐soluble initiators (azobisisobutyronitrile and benzoyl peroxide) than with a water‐soluble initiator (potassium persulfate). Benzoyl peroxide was particularly effective in yielding particles with a narrow size distribution. Although increasing amounts of a surfactant (sodium dodecyl sulfate) led to smaller particles, the choice of the monomer was the major determinant. For example, in polymerization reactions carried out at 85 °C with benzoyl peroxide as the initiator and with otherwise identical recipes, we obtained particle sizes of 181 nm with AlMeC, 296 nm with VEC, and 203 nm with DBAC. Fluorescent particles were synthesized with comonomers based on the benzothioxanthene nucleus. Because the dyes had poor solubility in the monomers, it was necessary to include typically 20 wt % bromobenzene or dichlorobenzene based on the monomer in the miniemulsion reaction mixture. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1999–2009, 2004     

Synthesis of snowman‐like polymer‐silica asymmetric particles by combination of hydrolytic condensation process with γ‐ray radiation initiated seeded emulsion polymerization

We report on a facile route to synthesize snowman‐like asymmetric composite particles via γ‐ray initiated seeded emulsion polymerization after a hydrolytic condensation process on the surface of second monomer swollen poly(styrene‐divinylbenzene‐acrylic acid) seeds. Effects of the amounts and kinds of second monomer and inorganic precursor, different radiation polymerization conditions including dose rates and absorbed doses on the morphology of the obtained particles were investigated. The obtained asymmetric particles can serve as ideal solid surfactants to stabilize the water‐in‐oil emulsions, and soap‐free hierarchical materials were obtained by polymerization of monomers in water or oil phase. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 339–348     

Synthesis of hydrophilic polymers in supercritical carbon dioxide in the presence of a siloxane‐based macromonomer surfactant: Heterogeneous polymerization of 1‐vinyl‐2 pyrrolidone

Batch free radical polymerization of 1‐vinyl‐2‐pyrrolidone (VP) in supercritical carbon dioxide (scCO₂) was studied in the presence of a reactive polysiloxane surfactant (PDMS‐mMA). Phase behavior investigation showed that when the initial concentration of the surface active macromonomer was higher than 2.5% w/w with respect to the monomer, the reaction mixture, in the absence of efficient stirring, was initially opaque to the visible light, and it slowly turned to an orange tint. Polymerization experiments carried out with surfactant concentration higher than the aforementioned value proceeded with a fast kinetics, and led to the formation of spherical nanoparticles with almost quantitative yields (higher than 98% with a reaction time lower than 70 min). The effect of the concentration of the surface active macromonomer, the initiator and the monomer, and of the density of the fluid phase on the kinetics of the process and on the morphology of the particles was investigated. A marked decrease of the number‐average diameter of the polymer particles with the surfactant concentration was obtained without any particle agglomeration. A dependence on [Initiator]^?0.16 of the particle diameter was observed. Such scaling law exhibits an exponent higher than any previously reported for dispersion processes and rather close to those foreseeable on the basis of Smith–Harkins kinetics for emulsion polymerization. Collected experimental results strongly suggest that the polymerization of VP in the presence of PDMS‐mMA could proceed with a nucleation mechanism different from that postulated in pure dispersion polymerization stabilized by graft‐forming surfactants. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 173–185, 2004