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Krzysztof Matyjaszewski - One of the best experts on this subject based on the ideXlab platform.
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calorimetric study of block copolymers of poly n Butyl Acrylate and gradient poly n Butyl Acrylate co methyl methAcrylate
Polymer, 2002Co-Authors: A Buzin, M Pyda, Philip J Costanzo, Krzysztof Matyjaszewski, Bernhard WunderlichAbstract:Abstract The nanophase separation in diblock and triblock copolymers consisting of immiscible poly(n-Butyl Acrylate) (block A) and gradient copolymers of methyl methAcrylate (MMA) and n-Butyl Acrylate (nBA) (block M/A) were investigated by means of their heat capacity, Cp, as a function of the composition of the blocks M/A and temperature. In all copolymers studied, both blocks are represented by their Cp and glass transition temperature, Tg, as well as the broadening of the transition-temperature range. The low-temperature transition of the blocks A is always close to that of the pure poly(n-Butyl Acrylate) and is independent of the analyzed compositions of the block copolymer, but broadened asymmetrically relative to the homopolymer due to the small phase size. The higher transition is related to the glass transition of the copolymer block of composition M/A. Besides the asymmetric broadening of the transition due to the phase separation, it decreases in Tg and broadens, in addition, symmetrically with increasing Acrylate content. The concentration gradient is not able to introduce a further phase separation with a third glass transition inside the M/A block.
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atom transfer radical polymerization of tert Butyl Acrylate and preparation of block copolymers
Macromolecules, 2000Co-Authors: Krzysztof MatyjaszewskiAbstract:Atom transfer radical polymerization (ATRP) of tert-Butyl Acrylate is reported. Controlled polymerizations were performed using a CuBr/N,N,N‘,N‘ ‘,N‘ ‘-pentamethyldiethylenetriamine catalyst system in conjunction with an alkyl bromide as the initiator. Low molecular weight polymers with narrow molecular weight distributions were obtained by the addition of a solvent to create a homogeneous catalytic system. The addition of the solvent was necessary to decrease the polymerization rate and afford low polydispersity materials. This differs from the ATRP of methyl or n-Butyl Acrylate using this catalytic system, which do not require the addition of a solvent to obtain well-defined polymers. Subsequent hydrolysis of the polymer in refluxing dioxane with addition of HCl afforded poly(acrylic acid). Characterization using 1H NMR and FT-IR confirmed complete hydrolysis of the ester group. Further use of poly(tert-Butyl Acrylate) as a macroinitiator for block copolymerizations followed by hydrolysis of the ester g...
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atom transfer radical copolymerization of styrene and n Butyl Acrylate
Macromolecules, 1999Co-Authors: Stephen V Arehart, Krzysztof MatyjaszewskiAbstract:Styrene and n-Butyl Acrylate were copolymerized by atom transfer radical polymerization catalyzed by CuBr/4,4‘-di(5-nonyl)-2,2‘-bipyridine. Composition was consistent with a simple terminal model analysis and was independent of [CuBr]0, [I]0, and temperature for copolymerizations with initial feed content of styrene (fst)0 = 0.510. Monomer reactivity ratios evaluated from experimental data by nonlinear least-squares calculations were 0.68 ≤ r1 ≤ 0.82 and 0.22 ≤ r2 ≤ 0.26. 13C NMR spectra of styrene/n-Butyl Acrylate copolymers were very similar to copolymers prepared through conventional radical polymerizations, indicating that carbon-centered free radicals were generated under these conditions. Conversion/molecular weight plots showed no evidence of transfer, though measured molecular weights were consistently higher than theoretical ones. Semilogarithmic plots of monomer conversion versus time were nonlinear, indicating an irreversible termination reaction whose contribution decreases with decreasing tem...
Devon A Shipp - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of poly(tert‐Butyl Acrylate‐block‐vinyl acetate) copolymers by combining ATRP and RAFT polymerizations
Journal of Polymer Science Part A, 2008Co-Authors: Christy D. Petruczok, Richard F. Barlow, Devon A ShippAbstract:The synthesis of poly(tert-Butyl Acrylate-block-vinyl acetate) copolymers using a combination of two living radical polymerization techniques, atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization, is reported. The use of two methods is due to the disparity in reactivity of the two monomers, viz. vinyl acetate is difficult to polymerize via ATRP, and a suitable RAFT agent that can control the polymerization of vinyl acetate is typically unable to control the polymerization of tert-Butyl Acrylate. Thus, ATRP was performed to make poly(tert-Butyl Acrylate) containing a bromine end group. This end group was subsequently substituted with a xanthate moiety. Various spectroscopic methods were used to confirm the substitution. The poly(tert-Butyl Acrylate) macro-RAFT agent was then used to produce (tert-Butyl Acrylate-block-vinyl acetate). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7200–7206, 2008
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Preparation of Poly(styrene-block-Butyl Acrylate) Block Copolymer−Silicate Nanocomposites
Chemistry of Materials, 2003Co-Authors: Hanying Zhao, Devon A ShippAbstract:An initiator was intercalated into the interlayer spacings of montmorillonite clay, from which poly(styrene-block-Butyl Acrylate) silicate nanocomposites were prepared using atom transfer radical polymerization. A mixture of exfoliated structure and intercalated structure was produced in the nanocomposite. The poly(Butyl Acrylate) chains form microdomains with an average size of 2−5 nm.
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preparation of poly styrene block Butyl Acrylate block copolymer silicate nanocomposites
Chemistry of Materials, 2003Co-Authors: Hanying Zhao, Devon A ShippAbstract:An initiator was intercalated into the interlayer spacings of montmorillonite clay, from which poly(styrene-block-Butyl Acrylate) silicate nanocomposites were prepared using atom transfer radical polymerization. A mixture of exfoliated structure and intercalated structure was produced in the nanocomposite. The poly(Butyl Acrylate) chains form microdomains with an average size of 2−5 nm.
Bernhard Wunderlich - One of the best experts on this subject based on the ideXlab platform.
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calorimetric study of block copolymers of poly n Butyl Acrylate and gradient poly n Butyl Acrylate co methyl methAcrylate
Polymer, 2002Co-Authors: A Buzin, M Pyda, Philip J Costanzo, Krzysztof Matyjaszewski, Bernhard WunderlichAbstract:Abstract The nanophase separation in diblock and triblock copolymers consisting of immiscible poly(n-Butyl Acrylate) (block A) and gradient copolymers of methyl methAcrylate (MMA) and n-Butyl Acrylate (nBA) (block M/A) were investigated by means of their heat capacity, Cp, as a function of the composition of the blocks M/A and temperature. In all copolymers studied, both blocks are represented by their Cp and glass transition temperature, Tg, as well as the broadening of the transition-temperature range. The low-temperature transition of the blocks A is always close to that of the pure poly(n-Butyl Acrylate) and is independent of the analyzed compositions of the block copolymer, but broadened asymmetrically relative to the homopolymer due to the small phase size. The higher transition is related to the glass transition of the copolymer block of composition M/A. Besides the asymmetric broadening of the transition due to the phase separation, it decreases in Tg and broadens, in addition, symmetrically with increasing Acrylate content. The concentration gradient is not able to introduce a further phase separation with a third glass transition inside the M/A block.
Hanying Zhao - One of the best experts on this subject based on the ideXlab platform.
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Preparation of Poly(styrene-block-Butyl Acrylate) Block Copolymer−Silicate Nanocomposites
Chemistry of Materials, 2003Co-Authors: Hanying Zhao, Devon A ShippAbstract:An initiator was intercalated into the interlayer spacings of montmorillonite clay, from which poly(styrene-block-Butyl Acrylate) silicate nanocomposites were prepared using atom transfer radical polymerization. A mixture of exfoliated structure and intercalated structure was produced in the nanocomposite. The poly(Butyl Acrylate) chains form microdomains with an average size of 2−5 nm.
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preparation of poly styrene block Butyl Acrylate block copolymer silicate nanocomposites
Chemistry of Materials, 2003Co-Authors: Hanying Zhao, Devon A ShippAbstract:An initiator was intercalated into the interlayer spacings of montmorillonite clay, from which poly(styrene-block-Butyl Acrylate) silicate nanocomposites were prepared using atom transfer radical polymerization. A mixture of exfoliated structure and intercalated structure was produced in the nanocomposite. The poly(Butyl Acrylate) chains form microdomains with an average size of 2−5 nm.
A Buzin - One of the best experts on this subject based on the ideXlab platform.
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calorimetric study of block copolymers of poly n Butyl Acrylate and gradient poly n Butyl Acrylate co methyl methAcrylate
Polymer, 2002Co-Authors: A Buzin, M Pyda, Philip J Costanzo, Krzysztof Matyjaszewski, Bernhard WunderlichAbstract:Abstract The nanophase separation in diblock and triblock copolymers consisting of immiscible poly(n-Butyl Acrylate) (block A) and gradient copolymers of methyl methAcrylate (MMA) and n-Butyl Acrylate (nBA) (block M/A) were investigated by means of their heat capacity, Cp, as a function of the composition of the blocks M/A and temperature. In all copolymers studied, both blocks are represented by their Cp and glass transition temperature, Tg, as well as the broadening of the transition-temperature range. The low-temperature transition of the blocks A is always close to that of the pure poly(n-Butyl Acrylate) and is independent of the analyzed compositions of the block copolymer, but broadened asymmetrically relative to the homopolymer due to the small phase size. The higher transition is related to the glass transition of the copolymer block of composition M/A. Besides the asymmetric broadening of the transition due to the phase separation, it decreases in Tg and broadens, in addition, symmetrically with increasing Acrylate content. The concentration gradient is not able to introduce a further phase separation with a third glass transition inside the M/A block.
