Background: Atom transfer radical polymerization (ATRP) is considered to be one of the better and easier synthetic tools for the preparation of polymers with controlled molecular weights and polydispersities. Ambient temperature ATRP of tert-butyl acrylate (tBA) was studied in a detailed manner with ethyl 2-bromoisobutyrate (EBrB) and tert-butyl 2-bromoisobutyrate (tBuBrB) as the initiators for three different degrees of polymerization. Results: Details pertaining to the kinetics of polymerization using different initiators are reported. It is observed that dimethylsulfoxide accelerates the polymerization at room temperature. The use of Cu(II) as the deactivator produces very narrow dispersity polymers. A diblock copolymer, poly(tert-butyl acrylate)-block-poly(methyl methacrylate), was synthesized from the poly(tBA) macroinitiator demonstrating the controlled living nature of the polymerizations. Conclusions: The rate of polymerization is more rapid with a secondary initiator (ethyl 2-bromopropionate) compared to the tertiary initiators EBrB and tBuBrB. From the detailed kinetic results it is observed that tris(2-dimethylaminoethyl)amine was a better ligand compared to tris(2-aminoethyl)amine in terms of achieving controlled polymerization. © 2007 Society of Chemical Industry.

R. Dhamodharan

Department Of Chemistry

ATOM TRANSFER RADICAL POLYMERIZATION

Block copolymers

INITIATORS (CHEMICAL)

Polydispersity

Reaction kinetics

Temperature distribution

CONTROLLED LIVING POLYMERIZATION

DIMETHYLSULFOXIDE

TERT-BUTYL ACRYLATE

Polyacrylates

copolymer

Molecular weight

Polymerization

Temperature

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Polymer International

Controlled and very rapid ambient temperature polymerization of tert-butyl acrylate (tBA) via atom transfer radical polymerization (ATRP) and single electron transfer living radical polymerization (SET-LRP) conditions is reported. Two initiators, one that would generate a secondary radical and another that would generate a primary radical, upon activation, are used. A very active catalyst CuBr/Me 6TREN was found to initiate rapid polymerization whether it was the primary or the secondary initiator. The polymerization was well controlled and very rapid. The initiator that produces secondary initiating site is found to result in more rapid polymerization than the one that produces primary initiating site. To explore the possibility of rapid ambient temperature polymerization through the SET-LRP mechanism, the polymerization was also carried out in the presence of DMSO. It was found that the polymerization was much faster compared to the bulk ATRP, without loss of control. Styrene was block copolymerized from PtBA macroinitiators and vice versa. In both the cases, block copolymers with controlled molecular weights were obtained. The tBA block of the polymer was selectively hydrolyzed to get amphiphilic block copolymers. This amphiphilic block copolymer was found to be useful in preparing stable cadmium sulfide (CdS) nanoparticulate dispersion. © 2011 Wiley Periodicals, Inc.

Journal of Polymer Science, Part A: Polymer Chemistry

Controlled radical polymerization of tert-butyl acrylate at ambient temperature: Effect of initiator structure and synthesis of amphiphilic block copolymers

We demonstrate, for the first time, the synthesis of model poly(benzyl methacrylate) [P(BnMA)] brushes of very high thickness (>300 nm) on silicon wafer. P(BnMA) brush is also synthesized from the surface of silica nanoparticles, from a covalently anchored initiator monolayer, using ambient temperature ATRP. The kinetic studies and block copolymerization from the surface anchored P(BnMA)-Br macroinitiator showed that the polymerization was controlled in nature. AFM, ellipsometry, and water contact angle were used for the characterization of the polymer brush. The grafting density of the P(BnMA) brush, formed by immersion in a dilute monomer solution, was relatively less (∼11% less) in comparison to that obtained by immersion in neat monomer under similar conditions. The P(BnMA)-Br macroinitiator brushes were used to synthesize P(BnMA-b-S) diblock copolymer brushes by the ATRP of styrene at 95 °C. The P(BnMA-b-S) brushes showed stimulus response to a selective solvent and various nanopatterns were observed according to the composition of the block copolymer. © 2011 American Chemical Society.

Langmuir

Synthesis and morphological study of thick benzyl methacrylate-styrene diblock copolymer brushes

Isobornyl methacrylate (IBMA), a bulky hydrophobic methacrylate, undergoes very fast polymerization, in bulk, with Cu(I)Br/N,N,N′,N″,N″- pentamethyldiethylenetriamine (PMDETA)/ethyl-2-bromoisobutyrate system, at ambient temperature. IBMA also undergoes a spontaneous initiator-free polymerization, at ambient temperature, with Cu(I)Br/PMDETA catalytic system in dimethyl sulfoxide-water mixtures. The rate of the polymerization is seen to increase with the water content up to 80 mol % of water. A possible intervention of air in initiation is proposed. The active Cu(0) formed by the disproportionation of Cu(I) species in aqueous medium probably plays a vital role for a possible air-initiation of IBMA via single electron transfer-living radical polymerization (SET-LRP) mechanism. A high tolerance level to water under SET-LRP conditions is demonstrated. The poly(IBMA) samples obtained exhibit low molecular weight distributions (1.1-1.3). Similar behavior was not observed with other common methacrylates such as methyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate. © 2011 Wiley Periodicals, Inc.

Spontaneous Cu(I)Br-PMDETA-mediated polymerization of isobornyl methacrylate in heterogeneous aqueous medium at ambient temperature

A novel initiator containing pyrene, a fluorescent moiety, was prepared by reacting 1-aminopyrene and 2-bromoisobutyl bromide. The structure elucidation of the new initiator was carried out using various spectroscopic tools, as well as through single crystal X-ray diffraction studies. Novel, fluorescent amphiphilic block copolymers with a pyrene end-group, poly(styrene-b-acrylic acid) [P(S-b-AA)], poly(methyl methacrylate-b-dimethylaminoethyl methacrylate) [P(MMA-b-DMAEMA)], poly(styrene-b-tert-butyl acrylate) [P(S-b-t-BA)], poly(styrene-b-dimethylaminoethyl methacrylate) [P(S-b-DMAEMA)] were successfully synthesized by the atom transfer radical polymerization (ATRP) method, using CuBr as the catalyst and N,N,N′,N″,N″- pentamethyldiethylenetriamine (PMDETA)/N,N,N′,N″,N″- hexamethyltriethylenetetramine (HMTETA) as the complexing agent. The polymers were characterized by GPC, 1H-NMR, IR and UV-Vis spectroscopies. It was observed that as the polymerization time increased, both the conversion and the molecular weight increased linearly with time. The fluorescence properties of the polymers prepared were recorded. The physical properties and especially the pH dependent swelling properties of the amphiphilic block copolymers have been investigated. The utility of the block copolymers in the formation of stable dispersion of cadmium sulphide nanoparticles was investigated as a model study. Copyright © Taylor & Francis Group, LLC.

Journal of Macromolecular Science, Part A: Pure and Applied Chemistry

Exploration of novel pyrene labeled amphiphilic block copolymers: Synthesis via ATRP, characterization and properties

The ability to do very rapid bulk atom transfer radical polymerization (ATRP) of benzyl methacrylate using a CuX/PMDETA complex at room temperature was demonstrated in this study. The experimental conditions required to synthesize low- and high-molecular-weight poly(benzyl methacrylate) with low polydispersity are reported here. The controlled/living nature of the polymerization was demonstrated through kinetic studies, and chain-extension studies. © 2004 Wiley Periodicals, Inc.

Very Rapid Copper-Mediated Atom Transfer Radical Polymerization of Benzyl Methacrylate at Ambient Temperature

Novel bifunctional initiators [1,1′-Bi-2-naphthol bis(2-bromo-2-methylpropionate); (R)-, (S)-, and racemic-] were synthesized from the esterification of 1,1′-bi-2-naphthol and used as initiators in atom transfer radical polymerization (ATRP) in conjunction with N,N,N′,N′,N″-pentamethyldiethylenetriamine (PMDETA), and copper (I) bromide or copper (I) chloride. The initiators synthesized were completely characterized by UV, FTIR, NMR, and Mass spectroscopies. A detailed investigation of the ATRP of methyl methacrylate (MMA) with the bifunctional initiators (BBiBN) along with CuBr or CuCl/PMDETA catalyst system in anisole was carried out at 30°. Thus, MMA polymerization is shown to proceed with first-order kinetics, with predicted molecular weight, and narrow polydispersity indices. The ATRP of glycidyl methacrylate (GMA) and tert-butyl acrylate (tBA) were also performed with BBiBN initiator in conjunction with CuBr/PMDETA catalyst system. The polymerization of GMA was carried out at 30°C, but tBA was polymerized at 60°C. Gel permeation chromatography (GPC), FTIR, NMR, UV spectroscopies, and TGA were used for the characterization of the polymers synthesized. © 2004 Wiley Periodicals, Inc.

ATRP of methyl methacrylate using a novel binol ester-based bifunctional initiator

A detailed investigation of the atom transfer radical polymerization of methyl methacrylate (MMA) with the ethyl 2-bromoisobutyrate (2-EiBBr)/CuBr/N,N′,N′,N″-pentamethyldiethylenetriamine (PMDETA) catalyst system in anisole was performed at 30 °C. The number-average molecular weight of the PMMA was observed to increase gradually and linearly while the polydispersity index (PDI) remained narrow throughout the reaction time. The summary of these studies showed that PMMA with molecular weight up to 105 g/mol could be synthesized in a controlled fashion at room temperature. The new route developed was utilized to demonstrate the facile synthesis of ABC and CBABC multiblock copolymers of styrene, tert-butyl acrylate (tBA), and MMA. For this, the starting blocks of AB and BAB were synthesized by coupling different ATRP methods reported. The end-block consisting of PMMA was synthesized by the ATRP of MMA using the CuCl/PMDETA catalyst system (halogen exchange) with anisole as the solvent at room temperature. Gel permeation chromatography (GPC) was used to determine the Mn, Mw, and PDI of the polymers synthesized. The PDI of all the block copolymers is found to be low (1.1-1.4). 1H NMR spectroscopy was used to determine the chemical composition of the block copolymers. Additional evidence for the blocky nature was also gained from FT-IR and thermal analysis.

Macromolecules

Facile synthesis of ABC and CBABC multiblock copolymers of styrene, tert-butyl acrylate, and methyl methacrylate via room temperature ATRP of MMA

Journal of the American Chemical Society

Ultrafast Synthesis of Ultrahigh Molar Mass Polymers by Metal-Catalyzed Living Radical Polymerization of Acrylates, Methacrylates, and Vinyl Chloride Mediated by SET at 25 °C

Journal	Polymer International
ISSN	09598103
Open Access	No