Atom Transfer Radical Polymerization Of Styrene Research Articles

ICAR ATRP-induced surface self-assembly in the fabrication of the surface nanostructures

Polymerization induced surface self-assembly (PISSA) technology is a state-of-the-art method in the fabrication of the hierarchical surface nanostructures. Previously, we demonstrated that reversible addition−fragmentation chain transfer (RAFT) polymerization-based PISSA could be used to construct hierarchical surface nanostructures on the silica particles. Atom transfer radical polymerization (ATRP) has many advantages, especially in the synthesis of the macroinitiator. In this research initiators for continuous activator regeneration (ICAR) ATRP-induced PISSA approach is used to fabricate surface nanostructures. Poly(ethylene glycol) (PEG) macroinitiator and poly(oligo(ethylene glycol) monomethyl ether methacrylate-co-2-(2-bromoisobutyrnyloxy) ethyl methacrylate) (P(OEGMA-co-BIEM)) polymer brush macroinitiator on silica particles are used to initiate ATRP of styrene in methanol/water mixture. With the chain extensions, POEGMA-g-PS graft copolymer brushes and “free” PEG-b-PS block copolymer chains make surface coassembly into surface nanostructures. With an increase in monomer feeding ratio, the surface morphology gradually changes from small-sized spherical surface micelles (s-micelles), to big-sized s-micelles, and to asymmetric layered structures. Kinetics studies indicate that with an increase in monomer conversion there is a transition from homogeneous to heterogeneous polymerization.

One-Pot Synthesis of Block Copolymers via ATRP and ROP Using PCL Macroinitiator

Poly(lactide)-b-poly(ε-caprolactone)-b-poly(styrene) triblock copolymers were synthesized simultaneously by one-pot method using atom transfer radical polymerization (ATRP) and ring-opening polymerization (ROP) in one step. Firstly, brominated poly(ε-caprolactone) (PCL-Br) as macroinitiator was made via ROP of ε-caprolactone (ε-CL) in the existence of tin(II) 2-ethyl hexanoate at 110 °C followed by esterification with 2-bromopropionyl bromide. With the one-pot method, the simultaneously via ROP of D, Llactide in the existence of tin(II) 2-ethyl hexanoate and ATRP of styrene (St) monomer with PCL-Br macroinitiator in the presence of CuCl/PMDETA system using [I]: [CuCl]:[PMDETA]=1:1:3 molar ratios at 120 °C in toluene was performed. Thus, the block copolymers with controlled molecular weights and moderately narrow polydispersities were obtained. Principal parameters, such as monomer concentration, initiator concentration, and polymerization time, which effect the one-pot polymerization were investigated. The polymers obtained were characterized using 1H NMR, FTIR, and GPC technique.

Copper-catalyzed ARGET ATRP of styrene from ethyl α-haloisobutyrate in EtOAc/EtOH, using ascorbic acid/Na2CO3 as reducing system

Atom transfer radical polymerization (ATRP) is one of the most powerful techniques to synthesize precisely tailored polymers and macrostructures. Activators regenerated by electron transfer (ARGET) ATRP was developed as a “green” strategy to decrease the load of the metal catalyst. However, ARGET ATRP usually uses not-so-green reducing agents (e.g. Sn2+) or expensive and industrially impractical procedures. For these reasons, we report an ARGET ATRP of styrene with various carbonates as reducing agents, both alone and paired with ascorbic acid (AA), using monofunctional initiators and Cl or Br as exchanging atoms. The solvent mixture is composed of the green combination of EtOAc and EtOH, even in the presence of modest amounts of H2O. Cyclic voltammetry was used to evaluate the effect of H2O on the catalyst, as well as the absence of AA. The system returned high yields and low dispersities with low amounts of catalyst (~60 ppm) and moderate reaction times. Excellent results were obtained only with the Cl-ATRP system. NMR spectroscopy and kinetic analyses proved the livingness of the final polymer chains.

L‐menthol‐based initiators for atom transfer radical polymerization of styrene

ABSTRACTTwo new atom transfer radical polymerization (ATRP) initiators, 2‐isopropyl‐5‐methylcyclohexyl 2‐bromopropanoate (1) and 2‐Isopropyl‐5‐methylcyclohexyl 2‐bromo‐2‐methylpropanoate (2), have been synthesized by the reaction of 2‐bromopropanoyl bromide and 2‐bromo‐2‐methylpropanoyl bromide, respectively, with L‐menthol and characterized by 1H and 13C NMR and FTIR spectroscopic studies. ATRP of styrene has successfully been carried out in a control manner using these initiators along with catalyst/ligand system consisting of Cu(I)Br/N,N,N /,N /,N //‐pentamethyldiethylenetriamine. Polymerizations have yielded polystyrenes (PSts) of controlled molecular weight with low polydispersity index having a menthyl end group, as confirmed by 1H NMR and gel permeation chromatography [GPC]. The controlled nature of the polymerization has also been confirmed by kinetic study of the polymerization process monitored via 1H NMR and GPC. Initiator 2 has evolved as most efficient among the two. The obtained end‐functional PSt has also been used as a macroinitiator for homochain extension with styrene and heterochain extension with methyl methacrylate to produce PSt‐b‐PMMA, showing the living nature of the polymerization process. In comparison with the PSt sample prepared using widely used initiator ethyl‐2‐bromo‐isobutyrate with almost the same molecular weight and polydispersity, initiator 2‐made L‐menthyl‐capped PSt has shown higher light transmission properties of its dichloromethane solution at ~259 nm, higher thermal stability, lower glass transition temperature, a broad melting temperature, and higher surface roughness over its film. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47964.

Synthesis of Block Copolymers of Polyester and Polystyrene by Means of Cross-Metathesis of Cyclic Unsaturated Polyester and Atom Transfer Radical Polymerization

Synthesis of B–A–B type triblock copolymers of aliphatic polyester (PEs) and polystyrene (PSt) was investigated by using cyclic unsaturated PEs prepared by conventional polycondensation of 4-octene-1,8-diol and sebacoyl chloride. The obtained cyclic PEs underwent cross-metathesis with PSt containing a carbon–carbon double bond (C═C) at the central position, which was obtained by atom transfer radical polymerization (ATRP) of styrene with a bifunctional initiator containing a C═C bond. PSt with a longer methylene spacer between the C═C bond and PSt successfully afforded the PSt-b-PEs-b-PSt triblock copolymer. As another approach to obtain the triblock copolymer, cross-metathesis of cyclic PEs with 2-butene-1,4-diol or 4-octene-1,8-diol bis(2-bromoisobutyrylate)s was conducted to afford linear PEs having ATRP initiation sites at both ends, followed by ATRP of styrene. The unsaturated PEs segment in the triblock copolymer obtained by the second approach was converted into a saturated PEs segment by treatment...

Grafting of Polymer Brushes from Xanthate-Functionalized Silica Particles.

Monodisperse silica particles (SiPs) were surface-modified with a newly designed silane coupling agent comprising a triethoxysilane and an alkyl halide, namely, 6-(triethoxysilyl)hexyl 2-bromopropionate, which was further treated with potassium O-ethyl dithiocarbonate (PEX) to immobilize xanthate molecules on the particle surfaces. Surface-initiated macromolecular design via interchange of xanthates (MADIX) polymerization of vinyl acetate (VAc) was conducted with the xanthate-functionalized SiPs. The polymerization was well controlled and produced SiPs coated with poly(vinyl acetate) (PVAc) with a well-defined target molar mass and a graft density of about 0.2 chains nm-2 . Dynamic light scattering and TEM measurements revealed that the hybrid particles were highly dispersible in good solvents without any aggregation. The PVAc brushes were hydrolyzed with hydrochloric acid to produce poly(vinyl alcohol) brushes on the SiP surfaces. In addition, the number of xanthate molecules introduced on the SiP surfaces could be successfully controlled by adjusting the concentration of PEX. Thus, the SiPs have two functionalities: xanthates able to act as a MADIX chain-transfer agent and alkyl bromide initiation sites for atom transfer radical polymerization (ATRP). By using these unique bifunctional particles, mixed polymer brushes were constructed on the SiPs by MADIX of VAc followed by ATRP of styrene or methyl methacrylate.

Sequential synthesis of well-defined poly(vinyl acetate)-block-polystyrene and poly(vinyl alcohol)-block-polystyrene copolymers using difunctional chloroamide-xanthate iniferter

The sequential synthesis of well-defined poly(vinyl acetate)-block-polystyrene copolymer (PVAc-b-PS) and poly(vinyl alcohol)-block-polystyrene copolymer (PVA-b-PS) is challenging due to inactive vinyl acetate monomer and active styrene monomer. In this study, sequential polymerizations of vinyl acetate and styrene monomer were carried out by reversible addition-fragmentation chain transfer (RAFT) and atom transfer radical polymerization (ATRP) using an innovative amide based difunctional chloroamide-xanthate iniferter [S-(1-((3-(2-chloropropanamido)propyl) amino)-1-oxopropan-2-yl) O-ethyl xanthate]. Synthesized difunctional iniferter was very stable under basic condition and allowed the sequential reactions without chain-end modification and purification steps. Synthesized iniferter was first used for xanthate-mediated RAFT polymerization of VAc, followed by ATRP of styrene to achieve controlled molecular weight of PVAc-b-PS with lower polydispersity (≤1.3). Then, PVAc-b-PS was successfully converted to the corresponding PVA-b-PS by hydrolysis. Synthesized block copolymers were characterized by size exclusion chromatography, nuclear magnetic resonance spectroscopy, transmission electron microscopy, and dynamic light scattering.

Control of Radiation/Living Graft Polymerization in the Solid State

AbstractA novel approach for the preparation of well‐defined graft polymers is applied to poly(ether ether ketone) (PEEK) substrates, using a combination of radiation‐induced graft polymerization (RIGP) and atom transfer radical polymerization (ATRP). The ATRP of styrene (St) and styrene sulfonic acid ethyl ester (ETSS) has successfully proceeded from the macroinitiators, which are introduced by RIGP of chloromethylstyrene in the solid‐state PEEK substrates at 50 °C under conditions where no thermal polymerization takes place. By optimizing the catalyst concentration, the grafting degree of St and ETSS increases linearly up to ≈112 and 381%, followed by a unique rapid increase at a speed similar to that observed in solution ATRP. The living nature of the propagating radicals at the terminal of grafted polymers is confirmed by successive ATRP of St from the St‐grafted PEEK films, which are isolated after an initial round of ATRP of St.

Amphiphilic block copolymer poly(lactic acid)-block -(glycidylazide polymer)-block -polystyrene: synthesis and self-assembly

The triblock energetic copolymer PLA-b-GAP-b-PS was synthesized successfully through atom-transfer radical polymerization (ATRP) of styrene and ring-opening polymerization of d,l-lactide. The energetic macroinitiator GAP-Br, which was made from reacting equimolar glycidyl azide polymer (GAP) with α-bromoisobutyryl bromide, firstly triggered the ATRP of styrene with its bromide group, and then the hydroxyl group on the GAP end of the resulting diblock copolymer participated in the polymerization of lactide in the presence of stannous octoate. The triblock copolymer PLA-b-GAP-b-PS had a narrow distribution of molecular weight. In the copolymer, the PS block was solvophilic in toluene and improved the stability of the structure, the PLA block was solvophobic in toluene and served as the sacrificial component to prepare porous materials, and GAP was the basic and energetic material. The three blocks of the copolymer were fundamentally thermodynamically immiscible, which lead to the self-assembly of the block copolymer in solution. Further studies showed that the concentration and solubility of the copolymer and the polarity of the solvent affected the morphology and size of the micelles generated from the self-assembly of the PLA-b-GAP-b-PS block copolymer. The micelles generated in organic solvents at 10 mg/mL copolymer concentration were spherical but became irregular when water was used as a co-solvent. The spherical micelles self-assembled in toluene had three distinct layers, and the diameter of the micelles increased from 60 to 250 nm as the concentration of the triblock energetic copolymer increased from 5 to 15 mg/L.

Non-carbene Complex [RuCl2(PPh3)2(azocane)] as Active Catalyst Precursor for ROMP and ATRP

The novel, non-carbene complex [RuCl2(PPh3)2(azocane)] (1) of trigonal bipyramid geometry was synthesized, characterized (CHN elementary analysis, FTIR, EPR, and 31P NMR), and applied as catalyst precursor for ring opening metathesis polymerization (ROMP) and atom transfer radical polymerization (ATRP). ROMP of norbornene (NBE) resulted in 70% yield at 50 °C in 60 min, with [NBE]/[1] = 5000, and 15% yield from ROMP of norbornadiene was obtained under the same conditions. ATRP of methyl methacrylate (MMA) resulted in ca. 20% conversion at 85 °C in 9 h, with [MMA]/[1] = 1000, and increased to ca. 50% in the presence of Al(OiPr)3, with narrower PDI values. With [MMA]/[1] = 200, ca. 50% yield was obtained at 85 °C in 6 h either in the absence or presence of Al(OiPr)3. ATRP of styrene resulted in 9 and 16% conversion at 110 °C in 7 h in the absence or presence of Al(OiPr)3, respectively, with [St]/[1] = 1000. Results are discussed considering the five-coordinated molecular geometry of the starting complex and the arrangements required in ROMP and ATRP to initiate the reactions.

Synthesis of PS-b-PPOA-b-PS triblock copolymer via sequential free radical polymerization and ATRP

A novel ABA triblock copolymer comprising double-bond-containing poly(phenoxyallene) (PPOA) and polystyrene (PS) segments was synthesized by sequential conventional free radical polymerization and atom transfer radical polymerization (ATRP) via the site transformation strategy. A new bifunctional initiator containing azo and Br-containing ATRP initiating groups was prepared using 2-bromopropionyl chloride, hydroquinone, and 4,4′-azobis(4-cyanopentanoic acid) as starting materials. Conventional free radical homopolymerization of phenoxyallene with cumulated double bond was performed in toluene to provide a polyallene-based macroinitiator bearing ATRP initiating groups at both ends, which is stable under UV irradiation and free radical circumstances. PS-b-PPOA-b-PS triblock copolymer was then obtained by bulk ATRP of styrene initiated by PPOA-based macroinitiator. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1366–1372

Synthesis of Well-Defined Polyethylene-Based 3-Miktoarm Star Copolymers and Terpolymers

Novel polyethylene (PE)-based 3-miktoarm star copolymers A2B, (AB)2B and terpolymers (AC)2(BC) [A: PE; B, C: polystyrene (PS) or poly(methyl methacrylate) (PMMA)] were synthesized by combining boron chemistry, polyhomologation, and atom transfer radical polymerization (ATRP). 1,4-Pentadiene-3-yl 2-bromo-2-methylpropanoate was first synthesized followed by hydroboration with thexylborane to afford B-thexylboracyclanes, a multi-heterofunctional initiator with two initiating sites for polyhomologation and one for ATRP. After polyhomologation of dimethylsulfoxonium methylide the α,ω-dihydroxyl polyethylene (PE-OH)2-Br produced served as macroinitiator for the ATRP of styrene to afford (PE-OH)2-(PS-Br). Both (PE-OH)2-Br and (PE-OH)2-(PS-Br) were transformed to two new trifunctional macroinitiators (PE-Br)2-Br and (PE-Br)2-(PS-Br) through esterification reactions and used for the synthesis of (AB)2B and (AC)2(BC) 3-miktoarm star co/terpolymers. All intermediates and final products were characterized by 1H NMR, ...

Styrene ATRP using the new initiator 2,2,2-tribromoethanol: Experimental and simulation approach

Atom transfer radical polymerization (ATRP) is a powerful technique for the controlled synthesis of polymers, and one of the most important ATRP characteristics is the possibility to produce functionalized polymers. 2,2,2-Tribromoethanol appears as a promising initiator for the ATRP process, because it allows the production of polymers with end hydroxyl groups, making it easy for copolymerization with biomonomers. This article explores, in experimental and computational level, the styrene ATRP using 2,2,2-tribromoethanol to understand how this new initiator behaves, and presents a powerful tool to predict the polymer properties for different operating conditions. Simulations and experimental results showed that polymers with high molecular weight and low PDI can be simultaneously obtained using 2,2,2-tribromoethanol as initiator. For all operational conditions, the reaction was fast and polydispersity values kept lower than 1.4, confirming the “living”/controlled characteristic. The polymers produced contain hydroxyl as functional group and in some operating conditions, PDI values of 1.1 was obtained, even at high monomer conversion. POLYM. ENG. SCI., 55:2270–2276, 2015. © 2015 Society of Plastics Engineers

Diselenocarbamates, novel initiators in ATRP of styrene

ABSTRACTThe atom transfer radical polymerizations (ATRPs) of styrene initiated by diselenocarbamates were carried out for the first time. The polymerization showed first‐order kinetic with respect to the monomer concentration, and the molecular weights of the obtained polymers increased linearly with the monomer conversions with narrow molecular weight distributions (as low as 1.16). The results of chain extension, 1H NMR, UV–vis, and MALDI‐TOF MS confirmed that the resultant polystyrene possessed some degree of living diselenocarbamates terminal. However, significant amounts of dead polymers (about 53%) were also found. This work offered an alternative type of ATRP initiator, and the seleno‐terminated polymers may be useful in biotechnological and biomedical applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1927–1933

Kinetic study of styrene atom transfer radical polymerization from hydroxyl groups of graphene nanoplatelets: Heterogeneities in chains and graft densities

Confinement effect of graphene nanoplatelets on the kinetics of styrene atom transfer radical polymerization was studied by a “grafting from” reaction. Graphene oxide was modified by different amounts of (3-aminopropyl) triethoxysilane and then alpha-bromoisobutyryl bromide from the hydroxyl groups. Polymerization of styrene in the presence of modified graphene and free initiator, ethyl alpha-bromoisobutyrate, was accomplished at 110°C. Then, effect of various graft densities and different graphene loadings on the heterogeneous graft and free polystyrene chains characteristics and also kinetics of polymerization was studied by gas and gel permeation chromatographies. Efficiency of grafting reactions along with the graft contents was studied by X-ray photoelectron spectroscopy, elemental analysis, and thermogravimetric analysis. Confinement effects of graphene on the relaxation behavior of polystyrene chains and also morphology of the graphenes were studied by differential scanning calorimetry and transmission electron microscopy, respectively. POLYM. ENG. SCI., 55:1720–1732, 2015. © 2014 Society of Plastics Engineers

Copper(II) complexes of bis(aryl-imino)acenaphthene ligands: synthesis, structure, DFT studies and evaluation in reverse ATRP of styrene.

Two new Ar-BIAN Cu(II) complexes (where Ar-BIAN = bis(aryl-imino)acenaphthene) of formulations [CuCl2(Mes-BIAN)] (1) (Mes = 2,4,6-Me3C6H2) and [CuCl2(Dipp-BIAN)] (2) (Dipp = 2,6-iPr2C6H3) were synthesised by direct reaction of CuCl2 suspended in dichloromethane with the respective ligands Mes-BIAN (L1) and Dipp-BIAN (L2), dissolved in dichloromethane, under an argon atmosphere. Attempts to obtain these compounds by solubilising CuCl2 in methanol and adding a dichloromethane solution of the corresponding ligand, under aerobic conditions, gave also compound 1, but, in the case of L2, the Cu(I) dimer [CuCl(Dipp-BIAN)]2 (3) was obtained instead of compound 2. The compounds were fully characterised by elemental analyses, MALDI-TOF mass spectrometry, FT-IR, (1)H NMR and EPR spectroscopic techniques. The solid-state molecular structures of compounds 1-3 were determined by single crystal X-ray diffraction, showing the expected chelation of the Ar-BIAN ligands and two chloride ligands completing the coordination sphere of the Cu(II) centre. In the case of the complex 1, an intermediate coordination geometry around the Cu(II) centre, between square planar and tetrahedral, was revealed, while the complex 2 showed an almost square planar geometry. The structural differences and evaluation of energetic changes were rationalised by DFT calculations. Analysis of the electrochemical behaviour of complexes 1-3 was performed by cyclic voltammetry and the experimental redox potentials for Cu(II)/Cu(I) pairs have been compared with theoretical values calculated by DFT in the gas phase and in dichloromethane and methanol solutions. The complex 1 exhibited good activity in the reverse atom transfer radical polymerisation (ATRP) of styrene.

Well‐Defined Iron Complexes as Efficient Catalysts for “Green” Atom‐Transfer Radical Polymerization of Styrene, Methyl Methacrylate, and Butyl Acrylate with Low Catalyst Loadings and Catalyst Recycling

Environmentally friendly iron(II) catalysts for atom-transfer radical polymerization (ATRP) were synthesized by careful selection of the nitrogen substituents of N,N,N-trialkylated-1,4,9-triazacyclononane (R3 TACN) ligands. Two types of structures were confirmed by crystallography: "[(R3 TACN)FeX2 ]" complexes with relatively small R groups have ionic and dinuclear structures including a [(R3 TACN)Fe(μ-X)3 Fe(R3 TACN)](+) moiety, whereas those with more bulky R groups are neutral and mononuclear. The twelve [(R3 TACN)FeX2 ]n complexes that were synthesized were subjected to bulk ATRP of styrene, methyl methacrylate (MMA), and butyl acrylate (BA). Among the iron complexes examined, [{(cyclopentyl)3 TACN}FeBr2 ] (4 b) was the best catalyst for the well-controlled ATRP of all three monomers. This species allowed easy catalyst separation and recycling, a lowering of the catalyst concentration needed for the reaction, and the absence of additional reducing reagents. The lowest catalyst loading was accomplished in the ATRP of MMA with 4 b (59 ppm of Fe based on the charged monomer). Catalyst recycling in ATRP with low catalyst loadings was also successful. The ATRP of styrene with 4 b (117 ppm Fe atom) was followed by precipitation from methanol to give polystyrene that contained residual iron below the calculated detection limit (0.28 ppm). Mechanisms that involve equilibria between the multinuclear and mononuclear species were also examined.

Modeling Atom‐Transfer Radical Polymerization of Butyl Acrylate

The kinetics of butyl acrylate (BA) atom‐transfer radical polymerization (ATRP) up to 2 000 bar has been modeled via PREDICI. A novel software package has been used in conjunction with PREDICI to perform automatic simulation and data processing within an extended range of polymerization conditions. The polymerization rate is enhanced with pressure, although to a weaker extent than in the ATRP of styrene and methyl methacrylate. Modeling suggests that intramolecular chain‐transfer in BA polymerization is significantly accelerated at high pressure.

Fe‐mediated ICAR ATRP of styrene and acrylonitrile in polyethylene glycol

ABSTRACTIn this contribution, random copolymers of p(styrene‐co‐acrylonitrile) via initiators for continuous activator regeneration (ICAR) in atom transfer radical polymerization (ATRP) (ICAR ATRP) of styrene and acrylonitrile (SAN) were synthesized at 90°C in low molecular weight polyethylene glycol (PEG‐400) using CCl4 as initiator, FeCl3·6H2O as catalyst, succinic acid as ligand and thermal radical initiator azobisisobutyronitrile (AIBN) as thermal free radical initiator. In this system, well‐defined copolymer of SAN was achieved. The kinetics results showed that the copolymerization rate obeyed first‐order kinetics model with respect to the monomer concentration, and a linear increase of the molecular weights with the increasing of monomer conversion with narrow molecular weight distribution was observed in the range of 1.1–1.5. The conversion decreased with increasing the amount of FeCl3·6H2O and increased with increasing the molar ratio of [St]0/[AN]0/[CCl4]0 and temperature. AIBN has a profound effect on the polymerization. The activation energy was 55.67 kJ mol−1. The living character of copolymerization was confirmed by chain extension experiment. The resultant random copolymer was characterized by 1H‐NMR and GPC. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40135.

Exploration of the Bulk Atom Transfer Radical Polymerization of Styrene

ABSTRACTThe synthesis of well‐defined polystyrene by atom transfer radical polymerization (ATRP) is reported. The effects of temperature, initiators, catalysts, and ligands on styrene bulk ATRP were investigated in detail. Results indicated that the initiator activity for a given monomer needs careful matching to bring about a match of the chain‐initiation and chain‐propagation rates. The higher activity is not necessarily the better. Thus, the less reactive monomer, styrene, was efficiently initiated by 1‐phenylethyl bromide (1‐PEBr), which only has a moderate initiator activity. Similarly, the catalyst system had to be carefully matched to achieve a real controlled/living radical polymerization. Controlled/living bulk ATRP of styrene was achieved by using 1‐PEBr as initiator, copper(I) bromide as catalyst, and N,N,N′,N′′,N′′‐ pentamethyldiethyllenetriamine as ligand at 90°C. After 4 h, the monomer conversion reached 51.8%, the practical molecular weight of polystyrene coincided well with the theoretical molecular weight of polystyrene, and the molecular weight distribution was 1.15. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21371; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21371