Gradient copolymers: Synthesis, structure, and properties

Zaremski, M. Yu.; Kalugin, Denis; Голубев, В. Б.

doi:10.1134/s0965545x09010088

Cited by 74 publications

(67 citation statements)

References 73 publications

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“…[3][4][5][6] Besides block copolymers, which possess sharp transitions at the conjunction of different blocks, gradient copolymers have created great interest recently. [7][8][9] Gradient copolymers are dened as a type of copolymer with a composition which continuously varies from head to tail of the polymer chains. Even in well-dened gradient copolymers, the local monomer sequence can not be exactly dened.…”

Section: Introductionmentioning

confidence: 99%

Tailor-made compositional gradient copolymer by a many-shot RAFT emulsion polymerization method

et al. 2014

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A many-shot RAFT emulsion polymerization method is proposed to synthesize gradient copolymers with high molecular weight and a tailor-made compositional gradient. In this method each shot consisting of comonomers with pre-set different fractions and targeting the molecular weight of 10 000 g mol À1 was added in a stepwise manner during the reaction. High conversions over 95% were achieved in 35 min after each shot. The compositional variation along the polymer chain was then directly determined by the comonomer fractions added at each shot. Styrene/n-butyl acrylate gradient copolymers (including linear and V-shaped gradient) with molecular weights as high as 90 000 g mol À1 were prepared by this method. The composition profiles along the polymer chains agreed well with the theoretical predictions, and the composition distribution among the polymer chains was narrow. The gradient copolymers showed different thermal and phase separation properties from their block counterparts, as expected.These results demonstrated the successful tailor-making of the gradient copolymers. The current strategy will act as a facile method to prepare tailor-made gradient copolymers with high molecular weights and within a short time.

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Section: Introductionmentioning

confidence: 99%

Tailor-made compositional gradient copolymer by a many-shot RAFT emulsion polymerization method

et al. 2014

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“…Gradient copolymers have received increasing attention due to their ability to achieve properties which are unavailable by homopolymers and traditional copolymers . Unlike block copolymers, which comprise an instantaneous switch between monomer units, gradient copolymers have a continuous compositional drift from one chain end to the other .…”

Section: Introductionmentioning

confidence: 99%

Exploring Quality in Gradient Copolymers

Elsen

et al. 2013

Macromol. Rapid Commun.

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Quality of gradient copolymers is evaluated by atomic force microscopy (AFM) and correlated with molecular weight distribution (MWD) values. ARGET ATRP is employed with decreasing levels of catalyst concentrations to generate copolymers with increasing M¯w/M¯n values. The copolymers are transformed into molecular bottlebrushes to enable imaging and analysis of individual molecules by AFM. The average height (cross-sectional) profile of all bottlebrushes agrees with the instantaneous composition (ICHEMA-TMS ) of the analogous copolymer backbone, as determined by (1) H NMR. The copolymer synthesized with 500 ppm of catalyst exhibits more narrow distributions of both brush height and backbone length when analyzed as a bottlebrush by AFM. Correspondingly, the copolymers synthesized with lower catalyst concentrations yield bottlebrushes with broader height and length distribution. These results establish MWD values as an excellent trait to assess quality within gradient copolymers.

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“…In the case of binary copolymerization, only one type of gradient macromolecules can be formed: copolymer chains are enriched with one component at the penalty of another component. In contrast to binary copolymerization, the scope of gradient macromolecules produced via ternary polymerization is more diverse.…”

Section: General Concept Of Living Radical Nitroxide‐mediated Terpolymentioning

confidence: 99%

Living Nitroxide‐Mediated Radical Terpolymerization: General Concept and Synthetic Possibilities

Zaremski

Plutalova

Eremeev

2016

Macro Theory & Simulations

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The general concept for nitroxide‐mediated radical terpolymerization is advanced. This concept is based on activation‐deactivation equilibria for terminal polymer‐nitroxide adducts. Depending on monomer activity and the stability of terminal nitroxide adducts, terpolymerization can be equilibrium living, quasi‐equilibrium (gradient) living, decaying living, decaying gradient, or non‐living. Expressions for the effective activation‐deactivation equilibrium constant, Kef, and the rate of terpolymerization are derived from theoretical speculations on equilibrium living and decaying living terpolymerization. For quasi‐equilibrium living terpolymerization, various types of gradient terpolymers are predicted. When activity of the active monomer M1 is, at least, one order of magnitude different from that of the two other monomers, the effective constant Kef is shown to approach K1 of the most active monomer. Experimental kinetic and equilibrium constants agree with the advanced concept for the equilibrium living terpolymerization of styrene with methyl methacrylate, and acrylonitrile in the presence of nitroxide SG1, as well as for decaying living terpolymerization in the same system in the presence of nitroxide TEMPO.

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Gradient copolymers: Synthesis, structure, and properties

Cited by 74 publications

References 73 publications

Tailor-made compositional gradient copolymer by a many-shot RAFT emulsion polymerization method

Tailor-made compositional gradient copolymer by a many-shot RAFT emulsion polymerization method

Exploring Quality in Gradient Copolymers

Living Nitroxide‐Mediated Radical Terpolymerization: General Concept and Synthetic Possibilities

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