Synthesis of block copolymers by atom transfer radical polymerization oftert-butyl acrylate with poly(oxyethylene) macroinitiators (original) (raw)
Related papers
European Polymer Journal, 2003
The synthesis of tert-butyl acrylate by atom transfer radical polymerization (ATRP) is reported. This polymer was prepared using FeCl 2 AE 4H 2 O(PPh 3 ) 2 catalyst system in conjunction with methyl 2-bromopropionate as initiator, in bulk and in solution using acetone as a solvent. The addition of solvent was necessary in order to decrease the polymerization rate and to afford low polydispersity polymers. The number-average molecular weights of the resulting polymers increased in direct proportion to the monomer conversion, and the polydispersities (M w =M n ) were as low as 1.2. In addition, the preparation of an AB diblock copolymer of poly (n-butyl methacrylate)-block-poly (tert-butyl acrylate) by ATRP is reported. The resulting polymers and copolymers were characterized by means of size exclusion chromatography and 1 H-NMR Spectroscopy.
Journal of Polymer Science Part A: Polymer Chemistry, 2005
The syntheses of triblock copolymers by the atom transfer radical polymerization of tert-butyl and iso-butyl acrylates as inner blocks with cyclohexyl methacrylate as outer blocks are reported. The living behavior and blocking efficiency of these polymerizations were investigated in each case. The use of difunctional macroinitiators led to ABA triblock copolymers with narrow polydispersities and controlled number-average molecular weights. These copolymers were prepared from bromo-terminated macroinitiators of poly(tert-butyl acrylate) and poly(iso-butyl acrylate), with copper chloride/N,N,N 0 ,N@,N@-pentamethyldiethylenetriamine as the catalytic system, at 40 8C in 50% (v/v) toluene solutions. The block copolymers were characterized with size exclusion chromatography and 1 H NMR spectroscopy. Differential scanning calorimetry measurements were performed to reveal the phase segregation. The glass transition of the inner block was not clearly detected, with the exception of the copolymer synthesized with the longest poly(iso-butyl acrylate) macroinitiator length.
Journal of Polymer Science Part A-polymer Chemistry, 2000
The synthesis of di-and triblock copolymers using atom transfer radical polymerization (ATRP) of n-butyl acrylate (BA) and methyl methacrylate (MMA) is reported. In particular, synthetic procedures that allow for an easy and convenient synthesis of such block copolymers were developed by using CuBr and CuCl salts complexed with linear amines. Polymerizations were successfully conducted where the monomers were added to the reactor in a sequential manner. Poor cross-propagation between poly(n-butyl acrylate) (PBA) macroinitiators and MMA was minimized, and therefore control of molecular weights and distributions was realized, by using halogen exchange-a technique involving the addition of CuCl to the MMA during the chain extension of the PBA macroinitiator. High molecular weight (M n ϳ 90,000) and low polydispersity (M w /M n Ͻ 1.35) ABA triblock copolymers were also prepared and their structure and properties in bulk have been preliminary characterized indicating the potential of ATRP for the production of all-acrylic thermoplastic elastomers.
European Polymer Journal, 2003
Homopolymerization of methyl acrylate (MA) and methyl methacrylate (MMA) by atom transfer radical polymerization (ATRP) were carried out at 90°C using methyl-2-bromopropionate (MBP) as initiator, copper halide (CuX, X ¼ Cl, Br) as catalyst, 2,2 0-bipyridine (bpy) or N,N,N 0 ,N 0 ,N 00-pentamethyldiethylenetriamine (PMDETA) as ligand in 1-butanol (less polar and containing OH) and acetonitrile (more polar) solvents. It was found that with CuCl/bpy catalyst ATRP of MA and MMA in 1-butanol proceeded faster than that in acetonitrile. The rate of ATRP of MA and MMA in acetonitrile and 1-butanol was comparable when CuCl/PMDETA used as catalyst system. The numberaverage molecular weights ðM n Þ increased with conversion and polydispersities were low ðM w =M n < 1:5Þ. The ATRP of MA and MMA with vinyl acetate telomer having trichloromethyl end group (PVAc-CCl 3) were also used to synthesize new block copolymers. The structures and molecular weight of synthesized PVAc-b-PMA and PVAc-b-PMMA were characterized by 1 H NMR, FTIR spectroscopy and gel permeation chromatography (GPC) and shown that the block copolymers were novel.
Macromolecules, 2002
Atom transfer radical polymerization (ATRP) was successfully applied to the synthesis of styrene-acrylonitrile (SAN) copolymers of predetermined molecular weights and low polydispersities. The monomers were copolymerized under azeotropic conditions (ca. 63 mol % styrene and 37 mol % acrylonitrile) in bulk using mono-and difunctional alkyl halide initiators such as 2-bromopropionitrile, 1-phenylethyl bromide, methyl 2-bromopropionate, poly(ethylene oxide) monomethyl ether 2-bromopropionate, and the bis(2-bromopropionate) esters derived from poly(ethylene oxide), poly(propylene oxide), or poly(-caprolactone) diols of various molecular weights in combination with two catalytic systems: CuBr/2,2′-bipyridine (bpy) and CuBr/N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (PMDETA). The synthesized copolymers had high chain end-functionalities, as proven by further chain extension with styrene, n-butyl, tert-butyl, or glycidyl acrylate, and methyl methacrylate. In the last case, the reaction in the presence of CuBr/bpy led to a block copolymer of high polydispersity, which was decreased to M w/Mn) 1.5 using halogen exchange (i.e., CuCl/bpy as the catalytic system). All other block copolymers (including di-, tri-, and pentablock copolymers) had narrow molecular weight distributions (Mw/Mn) 1.1-1.4).
Polymer Journal, 2008
Novel telechelic 2-methyl-2-bromopropionate terminated polyurethane macroinitiator was synthesized and used further to polymerize methyl methacrylate to yield poly(methyl methacrylate)-block-polyurethane-block-poly(methyl methacrylate) triblock copolymers through atom transfer radical polymerization. Number-average molecular weight (M n) was increased linearly with increasing polymerization time and conversion. Molecular weight distribution becomes narrower as the polymerization time increases and theoretical M n values of the tri-block copolymers were comparable to the experimental M n values. Structures of the macroinitiator and the tri-block copolymers were confirmed by 1 H NMR, 13 C NMR and FT-IR spectroscopic techniques. Mole percentage of poly(methyl methacrylate) in the triblock copolymers was calculated using 1 H NMR spectroscopy and was found to be comparable with the gel permeation chromatography results. Presence of two phases in the tri-block copolymers has been confirmed through differential scanning calorimetric studies.
ACS Applied Materials & Interfaces, 2012
Acrylic block copolymers have several advantages over conventional styrenic block copolymers, because of the presence of a saturated backbone and polar pendant groups. This investigation reports the preparation and characterization of di-and tri-block copolymers (AB and ABA types) of 2-ethylhexyl acrylate (EHA) and methyl methacrylate (MMA) via atom transfer radical polymerization (ATRP). A series of block copolymers, PEHA-block-PMMA(AB diblock) and PMMA-block-PEHA-block-PMMA(ABA triblock) were prepared via ATRP at 90 °C using CuBr as catalyst in combination with N, N, N´, N´´, N´´-pentamethyl diethylenetriamine (PMDETA) as ligand and acetone as additive. The chemical structure of the macroinitiators and molar composition of block copolymers were characterized by 1 H NMR analysis and molecular weights of the polymers were analyzed by GPC analysis. DSC analysis showed two glass transition temperatures (T g) indicating formation of two domains which was corroborated by AFM analysis. Small angle X-ray scattering (SAXS) analysis of AB and ABA block
High molecular weight diblock and ABA/ABC triblock copolymers of tert-butyl (meth)acrylate
Polymer International, 2012
AB diblock copolymers were prepared by use of poly(tert-butyl (meth)acrylate) (PtBA/PtBMA) as monofunctional macroinitiator in atom transfer radical polymerization of various (meth)acrylates (methyl, butyl) in the presence of the CuBr/N, N, N , N , Npentamethyldiethylenetriamine catalyst system. Then using the diblock copolymer as macroinitiator with a bromine atom at the chain end, ABC and ABA triblock copolymers containing at least one PtBA or PtBMA segment were synthesized via polymerization of the selected (meth)acrylic monomer. Gel permeation chromatography was applied to determine molecular weights and polydispersity indices. The latter, for block copolymers prepared without deactivator addition, were in the range 1.2-1.6 with a high degree of polymerization (150-500). The chemical compositions of the block copolymers were characterized with 1 H nuclear magnetic resonance. The kind of combined segments and their lengths influenced the glass transition temperature (T g) determined by differential scanning calorimetry.
Journal of Polymer Science Part A: Polymer Chemistry, 2008
Living-radical polymerization of acrylates were performed under emulsion atom transfer radical polymerization (ATRP) conditions using latexes prepared by a nanoprecipitation technique previously employed and optimized for the polymerization of styrene. A macroinitiator of poly(n-butyl acrylate) prepared under bulk ATRP was dissolved in acetone and precipitated in an aqueous solution of Brij 98 to preform latex particles, which were then swollen with monomer and heated. Various monomers (i.e. n-butyl acrylate, styrene, and tert-butyl acrylate) were used to swell the particles to prepare homo-and block copolymers from the poly(n-butyl acrylate) macroinitiator. Under these conditions latexes with a relatively good colloidal stability were obtained. Furthermore, amphiphilic block copolymers were prepared by hydrolysis of the tertbutyl groups and the resulting block copolymers were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The bulk morphologies of the polystyrene-b-poly(n-butyl acrylate) and poly(n-butyl acrylate)-b-poly(acrylic acid) copolymers were investigated by atomic force microscopy (AFM) and small angle X-ray scattering (SAXS).