Atom Transfer Radical Polymerization Of Styrene Research Articles

In situ atom transfer radical polymerization of styrene in the presence of nanoporous silica aerogel: Kinetic study and investigation of thermal properties

Atom transfer radical polymerization (ATRP) of styrene was performed at 110 °C in the presence of organically modified silica aerogel. A hydrophobic silica aerogel was prepared by a two-step, acid–base catalyzed sol–gel polymerization of tetraethoxysilane (TEOS) and surface modification by hexamethyldisilazane (HMDS) at the ambient pressure drying (APD) condition. Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption/desorption, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the silica aerogel. Kinetics of styrene ATRP was evaluated in the presence of silica aerogel. Molecular weight and molecular weight distribution were determined by gel permeation chromatography (GPC). There is a critical silica aerogel content that polymerization rate reaches to its lowest level. Thus, the sample with 1 wt% of silica aerogel shows minimum kapp with respect to the neat polystyrene. Differential scanning calorimetry (DSC) results reveals that competition between chains mobility and increase of molecular weight by addition of silica aerogel content results in an inconsiderable variation of the Tg value. The nanocomposite with 1 wt% of silica aerogel shows minimum Tg value (81.4 °C) respect to near polystyrene (94 °C). Transmission electron microscopy (TEM) was used to exhibit the pore size distribution of silica aerogel and either the disappearing of pores by a layer of polystyrene after polymerization.

Novel supramolecular block copolymer containing organic–inorganic pentablock copolymer by ATRP of styrene and vinyl acetate using polydimethylsiloxane/cyclodextrin inclusion complexes as macroinitiator

Organic–inorganic pentablock copolymers have been synthesized via atom transfer radical polymerization (ATRP) of styrene (St) and vinyl acetate (VAc) monomers at 60 °C using CuCl/N,N,N′,N″,N″-pentamethyldiethylenetriamine as a catalyst system initiated from boromoalkyl-terminated poly(dimethylsiloxane) (PDMS)/cyclodextrins macroinitiator (Br-PDMS/γ-CD). Br-PDMS-Br was reacted with γ-CD in different conditions with inclusion complexes being characterized through hydrogen nuclear magnetic resonance (1H NMR) and differential scanning calorimetry (DSC). Resulting Br-PDMS-Br/γ-CD inclusion complexes were taken as macroinitiators for ATRP of St and VAc. Well-defined poly(styrene)-b-poly(vinyl acetate)-b-poly(dimethylsiloxane/γ-cyclodextrin)-b-poly(vinyl acetate)-b-poly(styrene) (PSt-b-PVAc-b-PDMS/γ-CD-b-PVAc-b-PSt) pentablock copolymer was characterized by 1H NMR, gel permeation chromatograph (GPC) and DSC. There was a good agreement between the number-average molecular weight calculated from 1H NMR spectra and that of theoretically calculated. Pentablock copolymers consisting of Br-PDMS-Br/γ-CD inclusion complex as central blocks (inorganic block) and PVAc and PSt as terminal blocks were synthesized by this technique. PSt-b-PVAc-b-PDMS/γ-CD-b-PVAc-b-PSt pentablock copolymer can undergo a temperature-induced reversible transition upon heating of the copolymer complex from white complex at 22 °C to green complex in 55 °C which characterized with XRD and 1H NMR. XRD showed a change in crystallinity percent of St peak with changing the temperature which calculated by Origin75 software.

α‐Bis and α,ω‐tetrakis(4‐dimethylaminophenyl) functionalized polymers by atom transfer radical polymerization using 1,1‐bis[(4‐dimethylamino)phenyl]ethylene as tertiary diamine initiator precursor and functionalizing agent

The quantitative syntheses of α-bis and α,ω-tetrakis tertiary diamine functionalized polymers by atom transfer radical polymerization (ATRP) methods are described. A tertiary diamine functionalized 1,1-diphenylethylene derivative, 1,1-bis[(4-dimethylamino)phenyl]ethylene (1), was evaluated as a unimolecular tertiary diamine functionalized initiator precursor as well as a functionalizing agent in ATRP reactions. The ATRP of styrene, initiated by a new tertiary diamine functionalized initiator adduct (2), affords the corresponding α-bis(4-dimethylaminophenyl) functionalized polystyrene (3). The tertiary diamine functionalized initiator adduct (2) was prepared in situ by the reaction of (1-bromoethyl)benzene with 1,1-bis[(4-dimethylamino)phenyl]ethylene (1) in the presence of a copper (I) bromide/2,2′-bipyridyl catalyst system. The ATRP of styrene proceeded via a controlled free radical polymerization process to afford quantitative yields of the corresponding α-bis(4-dimethylaminophenyl) functionalized polystyrene derivative (3) with predictable number-average molecular weight (Mn) and narrow molecular weight distribution (Mw/Mn) in a high initiator efficiency reaction. The polymerization process was monitored by gas chromatography analysis. Quantitative yields of α,ω-tetrakis(4-dimethylaminophenyl) functionalized polystyrene (4) were obtained by a new post ATRP chain end modification reaction of α-bis(4-dimethylaminophenyl) functionalized polystyrene (3) with excess 1,1-bis[(4-dimethylamino)phenyl]ethylene (1). The tertiary diamine functionalized initiator precursor 1,1-bis[(4-dimethylamino)phenyl]ethylene (1) and the different tertiary amine functionalized polymers were characterized by chromatography, spectroscopy and non-aqueous titration measurements. Copyright © 2012 Society of Chemical Industry

INVESTIGATING THE EFFECT OF MCM-41 NANOPARTICLES ON THE KINETICS OF ATOM TRANSFER RADICAL POLYMERIZATION OF STYRENE

Effect of pristine and modified MCM-41 on the kinetics of styrene atom transfer radical polymerization (ATRP) was studied using a double bound containing modifier at 110°C. Conversion, molecular weight and PDI were obtained during the polymerization reactions to study the polymerization kinetics. Addition of the both types of MCM-41 has resulted in inconsiderable variations on the kinetics of polymerization. A similar trend is observed for the molecular weight of the free chains; however, increasing MCM-41 content results in higher PDI values. Also, surface modification of MCM-41 results in lower polymerization rates. In the case of grafted chains, molecular weight and PDI values increase by increasing MCM-41 content.

Synthesis and self-assembly behaviors of four-armed amphiphilic polystyrene-b-poly(N-isopropylacrylamide) copolymers

Four-armed amphiphilic block copolymers polystyrene-b-poly(N-isopropyl acrylamide) (PSt-b-PNIPAAM)4 were synthesized by atom transfer radical polymerization (ATRP) in two steps. Star narrow dispersed polystyrene, (PSt-Br)4, with controlled number-average molecular weight was firstly synthesized by ATRP of styrene (St) using pentaerythritol tetrakis (2-bromoisobutyrate) (4Bri-Bu) as four-armed initiator. Then, (PSt-b-PNIPAAM)4 was prepared using (PSt-Br)4 as macroinitiator by ATRP. The structures of (PSt-Br)4 and (PSt-b-PNIPAAM)4 were confirmed by characterization by nuclear magnetic resonance (1H NMR). The apparent viscosity of the four-armed (PSt-b-PNIPAAM)4 was significantly lower than that of the linear PSt-b-PNIPAAM with the same amount of repeat units of PSt and PNIPAAM. The self-assembly behavior of the four-armed amphiphilic block copolymers (PSt-b-PNIPAAM)4 in mixed solution (DMF/H2O) and the lower critical solution temperature (LCST) of the resulting micelles were investigated by scanning electron microscopy (SEM), dynamic light scattering (DLS) and UV-VIS spectroscopy. The results show that the size of the mono-dispersed spherical micelles decreased with the increment of the chain length of PNIPAAM in the block copolymers, while LCST increased.

A kinetic study of atom transfer radical polymerization of styrene with bis(2-pyridyl)ethylenedimethanimine derivative ligands

Atom transfer radical polymerization (ATRP) of styrene was carried out with multidentate nitrogen-based ligands, namely N,N'-bis[phenyl(pyrid-2-yl)methylene] ethane-1,2-diamine (BPDA) and N,N'-bis[methyl(pyrid-2-yl)methylene] ethane-1,2-diamine (BMDA), and catalyst systems at catalyst/ligand molar ratios of 1/0.33, 1/0.5, 1/1, and 1/1.5 by using 2 different initiators, (1-bromoethyl)benzene (BEB) and ethyl-2-bromopropionate (EBP). Linear first-order kinetic plots were observed for ATRP of styrene upon using BPDA as a ligand with both initiators. Even though the linear slopes indicate that radical concentration remains constant during reactions, high molecular weights were obtained at low conversion and showed a linear relation thereafter. To investigate the molecular weight effect, reactions were also performed in the presence of (1-bromoethyl)benzene initiator in dimethylformamide (DMF) for BPDA and in toluene for BMDA using a catalyst/ligand ratio of 1/1.

Dynamic polymer brushes on the surface of silica particles

Synthesis of cleavable PS brushes on the surface of silica particles was reported in this paper. Atom transfer radical polymerization (ATRP) initiator was anchored onto the surface of silica particles via dynamic imine bond, and PS brushes were prepared by surface ATRP of styrene. PS brushes could be cleaved from the surface of silica particles in the presence of trifluoroacetic acid. Based on the dynamic properties of imine bonds, pyrene-labeled silica particles were prepared through dynamic exchange reaction between PS brushes and 1-pyrenecarboxaldehyde. Moreover, silica particles with PS and fluorescein-labeled poly(methyl methacrylate) mixed polymer brushes were synthesized by dynamic exchange reaction. This research demonstrates that dynamic covalent chemistry provides an efficient method for the preparation of “dynamic” polymer brushes on silica particles.

Synthesis of biodegradable thermoplastic copolymers based on starch by atom transfer radical polymerization (ATRP): Monolayer chain growth on starch

AbstractModification of starch is increasingly being studied and starch is used for applications in which synthetic polymers have traditionally been the materials of choice. In this work the surface of starch was successfully modified by the polymerization of polystyrene and polyacrylamide by atom transfer radical polymerization (ATRP) method in dispersion medium. For this propose the bromoactylated starch was prepared by the reaction between hydroxyl groups of starch and the bromoacetyl bromide in DMA/LiCl (5%) in the presence of pyridine. The bromoactylated starch acts as macroinitiator in ATRP of styrene. The polymer chains' growth on surface of starch was clearly showed by the AFM images. Other analyses were used in this work such as FT‐IR, DSC, and TGA.

Synthesis of mikto-topology star polymer containing one cyclic arm

Well-defined mikto-topology star polystyrene composed of one cyclic arm and four linear arms was synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction. First, the bromine-alkyne α,ω-linear polystyrenes containing four hydroxyl groups protected with acetone-based ketal groups were synthesized by ATRP of styrene using a designed initiator. Then, the bromine end-group was converted to the azide and the linear polystyrene was cyclized intra-molecularly by the CuAAC reaction. The four hydroxyl groups were released by deprotection and then esterified with 2-bromoisobutyryl bromide to produce a cyclic polymer bearing four ATRP initiating units. By subsequent ATRP of styrene to grow linear polymers with the cyclic polystyrene as a macroinitiator, the mikto-topology star polymers were prepared. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Synthesis and characterization of six-arm star polystyrene-block-poly (3-hexylthiophene) copolymer by combination of atom transfer radical polymerization and click reaction

A novel six-arm star block copolymer comprising polystyrene (PS) linked to the center and π-conjugated poly (3-hexylthiophene) (P3HT) was successfully synthesized using a combination of atom transfer radical polymerization (ATRP) and click reaction. First, star-shaped PS with six arms was prepared via ATRP of styrene with the discotic six-functional initiator, 2,3,6,7,10,11-hexakis(2-bromoisobutyryloxy)triphenylene. Next, the terminal bromides of the star-shaped PS were substituted with azide groups. Afterward, the six-arm star block copolymer PS-b-P3HT was prepared using the click coupling reaction of azide-terminated star-shaped PS with alkynyl-terminated P3HT. Various techniques including 1H NMR, Fourier-transform infrared and size-exclusion chromatography were applied to characterize the chemical structures of the intermediates and the target block copolymers. Their thermal behaviors and optical properties were investigated using differential scanning calorimetry and UV–vis spectroscopy. Moreover, atomic force microscopy (AFM) was utilized to observe the morphology of the star block copolymer films. In comparison with two linear diblock copolymer counterparts, AFM results reveal the effect of the star block copolymer architecture on the microphase separation-induced morphology in thin films. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

α‐Bis and α,ω‐tetrakis(4‐dimethylaminophenyl) functionalized polymers by atom transfer radical polymerization using 1,1‐bis[(4‐dimethylamino)phenyl]ethylene as tertiary diamine initiator precursor and functionalizing agent

AbstractThe quantitative syntheses of α‐bis and α,ω‐tetrakis tertiary diamine functionalized polymers by atom transfer radical polymerization (ATRP) methods are described. A tertiary diamine functionalized 1,1‐diphenylethylene derivative, 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1), was evaluated as a unimolecular tertiary diamine functionalized initiator precursor as well as a functionalizing agent in ATRP reactions. The ATRP of styrene, initiated by a new tertiary diamine functionalized initiator adduct (2), affords the corresponding α‐bis(4‐dimethylaminophenyl) functionalized polystyrene (3). The tertiary diamine functionalized initiator adduct (2) was prepared in situ by the reaction of (1‐bromoethyl)benzene with 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1) in the presence of a copper (I) bromide/2,2′‐bipyridyl catalyst system. The ATRP of styrene proceeded via a controlled free radical polymerization process to afford quantitative yields of the corresponding α‐bis(4‐dimethylaminophenyl) functionalized polystyrene derivative (3) with predictable number‐average molecular weight (Mn) and narrow molecular weight distribution (Mw/Mn) in a high initiator efficiency reaction. The polymerization process was monitored by gas chromatography analysis. Quantitative yields of α,ω‐tetrakis(4‐dimethylaminophenyl) functionalized polystyrene (4) were obtained by a new post ATRP chain end modification reaction of α‐bis(4‐dimethylaminophenyl) functionalized polystyrene (3) with excess 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1). The tertiary diamine functionalized initiator precursor 1,1‐bis[(4‐dimethylamino)phenyl]ethylene (1) and the different tertiary amine functionalized polymers were characterized by chromatography, spectroscopy and non‐aqueous titration measurements. Copyright © 2012 Society of Chemical Industry

Three‐arm star block copolymers of aromatic polyether and polystyrene from chain‐growth condensation polymerization, atom transfer radical polymerization, and click reaction

AbstractWell‐defined (AB)3 type star block copolymer consisting of aromatic polyether arms as the A segment and polystyrene (PSt) arms as the B segment was prepared using atom transfer radical polymerization (ATRP), chain‐growth condensation polymerization (CGCP), and click reaction. ATRP of styrene was carried out in the presence of 2,4,6‐tris(bromomethyl)mesitylene as a trifunctional initiator, and then the terminal bromines of the polymer were transformed to azide groups with NaN3. The azide groups were converted to 4‐fluorobenzophenone moieties as CGCP initiator units by click reaction. However, when CGCP was attempted, a small amount of unreacted initiator units remained. Therefore, the azide‐terminated PSt was then used for click reaction with alkyne‐terminated aromatic polyether, obtained by CGCP with an initiator bearing an acetylene unit. Excess alkyne‐terminated aromatic polyether was removed from the crude product by means of preparative high performance liquid chromatography (HPLC) to yield the (AB)3 type star block copolymer (Mn = 9910, Mw/Mn = 1.10). This star block copolymer, which contains aromatic polyether segments with low solubility in the shell unit, exhibited lower solubility than A2B or AB2 type miktoarm star copolymers. In addition, the obtained star block copolymer self‐assembled to form spherical aggregates in solution and plate‐like structures in film. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Synthesize of polymer–silicate nanocomposites by in situ metal‐catalyzed living radical polymerization

AbstractPolymer–silicate nanocomposites were synthesized with atom transfer radical polymerization (ATRP). An ATRP initiator, consisting of a quaternary ammonium salt moiety and an α‐phenyl chloroacetyl chloride moiety, were intercalated into the interlayer spacings of the layered silicate. Subsequent ATRP of styrene with CuCl/2,2′‐bipyridine (bipy) as the catalyst with the initiator‐modified silicate afforded homopolymers with predictable molecular weights and low polydispersities, both characteristics of living radical polymerization. The polystyrene nanocomposites contained both intercalated and exfoliated silicate structures. The prepared materials were characterized by XRD, SEM, TEM, FTIR, and 1H NMR techniques. Effect of silicate on thermal properties and glass transition temperature of polystyrene was investigated using thermogravimetric analysis and differential scanning calorimetric techniques. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

ATRP of styrene catalyzed by elemental Fe(0) and Br2: An easy and economical ATRP process

AbstractIn this work, zero‐valent iron (Fe(0)) (powder or wire) and elemental bromine (Br2) were used as the catalysts for atom transfer radical polymerization (ATRP) of styrene (St) without any additional initiator at 110 °C. The polymerizations happened with controlled evidence at appropriate molar ratio of Fe(0) to Br2: a remarkable increase of molecular weights with St conversions, the narrow molecular weight distributions and living polymer chains end‐capped by Br. More Br2 or less Fe(0) led to a slow polymerization rate but an improved control over molecular weights. After examining the polymer chain ends by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, it was concluded that the polymerization was initiated by thermal self‐initiation, and regulated by the in situ generated FeIIIBr3. The results suggested that the Fe(0)/Br2 catalyzing polymerization was a classical ATRP process with easier operation and more economical components. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

ATRP–RCMpolymercyclization: synthesis of amphiphilic cyclic polystyrene-b-poly(ethylene oxide) copolymers

A novel amphiphilic block copolymer, i.e., cyclic polystyrene-b-poly(ethylene oxide) (cyclic PS-b-PEO 2), was synthesized through atom-transfer radical polymerization (ATRP), followed by ring-closing metathesis (RCM). Thus, a bromobenzyl-terminated PS-b-PEO-b-PS (6) was first prepared by ATRP of styrene using a PEO macroinitiator having 2-bromoisobutyryl groups (5). The subsequent end-group conversion into allyl groups was performed quantitatively with allyltrimethylsilane (ATMS) in the presence of TiCl4. The allyl-telechelic triblock copolymer PS-b-PEO-b-PS (7) thus obtained was subjected to metathesis polymer cyclization with a Grubbs' 2nd generation catalyst to produce amphiphilic cyclic PS-b-PEO (2).

Probing the effects of π-π stacking on the controlled radical polymerization of styrene and fluorinated styrene

The addition of the π–π stacking agent octafluorotoluene (OFT) resulted in up to a 50% reduction in monomer conversion after 24 h for atom transfer radical polymerization (ATRP) reactions of styrene, when performed at 85 °C with 1 eq of OFT compared with styrene in the initial reaction mixture. Monitoring the progress showed that the ATRP of styrene in the presence of either OFT or hexafluorobenzene (HFB) maintained a linear relationship between monomer conversion and number average molecular weights, while showing a first order rate dependence on monomer. The effects of π–π stacking on the KATRP could be overcome by using adjusting the redox activity of the metal-ligand complex while maintaining reaction temperatures of 85 °C. Further experiments showed that nitroxide-mediated polymerizations of St were affected to an identical extent by the presence of the π–π stacking agent HFB. The ATRP of pentafluorostyrene (PFSt) in the presence of π–π stackers benzene or toluene showed an increase in monomer conversion compared with reactions in their absence, consistent with Mn π–π stacking increasing the stability of the active radical. Interactions between the π–π stacking agents OFT and HFB and the aromatic groups in the ATRP of St or PFSt were verified by 1H NMR analysis. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Synthesis and characterization of BAB and CBABC tri- and PentaBlock copolymers via atom transfer radical polymerization

Atom transfer radical polymerization (ATRP) technique was applied successfully for the synthesis of poly(n-butyl methacrylate-b-styrene-b-n-butyl methacrylate) (PBMA-b-PS-b-PBMA), (BAB) and poly(methyl methacrylate-b-n-butyl methacrylate-b-styrene-b-n-butyl methacrylate-b-methyl methacrylate) (PMMA-b-PBMAb- PS-b-PBMA-b-PMMA), (CBABC) linear tri- and pentablock copolymers, respectively, in solution for the first time. Difunctional polystyrene macroinitiator that contains a bromide end-group was prepared by ATRP of styrene with dimethyl-2,6-dibromoheptanedioate (DMDBHD). The formation of block copolymers was confirmed by gel permeation chromatography (GPC), nuclear magnetic resonance (1H NMR) spectroscopy, and differential scanning calorimetry (DSC). Good agreement was observed between the theoretical and experimental molecular weights. The molecular weight distribution (MWD) was narrow and did not change much with the progress of the reaction. A linear increase in the number average molecular weight (M n ) with conversion was observed indicating that the polymerizations followed a ‘living’/controlled process. Both BAB and CBABC block copolymers showed core-shell type flower-like micellar structures when toluene is used as a selective solvent for A block (polystyrene). Open image in new window

Atom transfer radical polymerization of styrene and methyl (meth)acrylates initiated with poly(dimethylsiloxane) macroinitiator: Synthesis and characterization of triblock copolymers

AbstractPoly(dimethylsiloxane)(PDMS)‐based triblock copolymers were successfully synthesized via atom transfer radical polymerization (ATRP) initiated with bis(bromoalkyl)‐terminated PDMS macroinitiator (Br‐PDMS‐Br). First, Br‐PDMS‐Br was prepared by reaction between the bis(hydroxyalkyl)‐terminated PDMS and 2‐bromo‐2‐methylpropionyl bromide. PSt‐b‐PDMS‐b‐PSt, PMMA‐b‐PDMS‐b‐PMMA and PMA‐b‐PDMS‐b‐PMA triblock copolymers were then synthesized via ATRP of styrene (St), methyl methacrylate (MMA) and methyl acrylate (MA), respectively, in the presence of Br‐PDMS‐Br as a macroinitiator and CuCl/PMDETA as a catalyst system at 80 oC. Triblock copolymers were characterized by FTIR, 1H‐NMR and GPC techniques. GPC results showed linear dependence of the number‐average molecular weight on the conversion as well as the narrow polydispersity indicies (PDI < 1.57) for the synthesized triblock copolymers which was lower than that of Br‐PDMS‐Br macroinitiator (PDI = 1.90), indicating the living/controlled characteristic of the reaction. Also, there was a very good agreement between the number‐average molecular weight calculated from 1HNMR spectra and that calculated theoretically. Results showed that resulting copolymers have two glass transition temperatures, indicating that triblock copolymers have microphase separated morphology. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A novel semi-fluorinated graft copolymer containing perfluorocyclobutyl aryl ether-based backbone

The synthesis of a series of novel semi-fluorinated graft copolymers bearing perfluorocyclobutyl (PFCB) aryl ether-based backbone and polystyrene side chains is described. This work initially focused on the synthesis of a trifluorovinyl ether (TFVE) monomer containing a bromine atom, which could be employed as an initiating site for atom transfer radical polymerization (ATRP). Thermal cyclopolymerization of this TFVE monomer provided a macromolecular initiator followed by subsequent initiating ATRP of styrene to afford the desired PFCB aryl ether-based graft copolymers.

Evaluation of the confinement effect of nanoclay on the kinetics of styrene atom transfer radical polymerization

AbstractThe grafting through method was employed to study the effect of nanoclay confinement on the atom transfer radical polymerization (ATRP) of styrene. An ammonium salt containing a double bond on its structure was used as a clay modifier. Employing ATRP to polymerize styrene in the presence of modified montmorillonite resulted in a finely well‐defined polystyrene nanocomposite. The gas chromatography (GC) results showed the linear increase of ln(M0/M) versus time, which indicated the controlled behavior of the polymerization. Another confirmation of the living nature of the polymerization was the linear increase of molecular weight against monomer conversion concluded from the gel permeation chromatography (GPC) data. Nanoclay exerted acceleration on the polymerization of free polystyrene chains. The polydispersity indexes of polymer chains increased by the addition of nanoclay. In the case of clay‐attached polystyrene chains, number and weight‐average molecular weights were lower than that of freely dispersed polystyrene chains. The polydispersity index of the clay‐attached chains was higher in respect to the freely dispersed polystyrene chains. The living nature of polymer chains was more elucidated by Fourier transform infrared spectroscopy (FTIR). Exfoliation of the clay layers in the polymer matrix of polystyrene nanocomposite containing the lowest amount of nanoclay has proven by Transmission Electron Microscopy (TEM). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011