Qi Wang

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Name: Wang, Qi; 王齐

Organization: Zhejiang University , China

Department: Department of Polymer Science & Engineering

Title: Professor(PhD)

TOPICS

Polymer

Polyesters Polysulfone

Chemicals
References

Stereospecific reductive coupling polymerization of bis(benzylic gem-dibromide)s via formation of a trans-CC bond

Co-reporter:Hua Cao;Zhe Liu

Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 25) pp:3810-3814

Publication Date(Web):2017/06/27

DOI:10.1039/C7PY00525C

Stereospecific polymers were constructed by the successive formation of a trans-CC bond using bis(benzylic gem-dibromide)s as monomers treated with Cu/polyamine under mild conditions. The structure of the polymer was characterized by GPC, NMR, UV-vis and MALDI-TOF-MS. The formation of a trans-CC bond was established by a series of control reactions. Evidence demonstrates that the CC bond is generated by two domino reactions, one is the intermolecular reductive coupling reaction from gem-dibromide to vicinal dibromide and the other is the intramolecular debromination of vicinal dibromide, and therefore, the formation of a trans-CC bond. The successive formation of the trans-CC bond leads to the growth of a polymer chain following a step-growth polymerization mechanism.

E-Stilbene derivatives synthesized by stereoselective reductive coupling of benzylic gem-dibromide promoted by Cu/polyamine

Co-reporter:Hua Cao, Qi Wang

Tetrahedron Letters 2017 Volume 58, Issue 28(Issue 28) pp:

Publication Date(Web):12 July 2017

DOI:10.1016/j.tetlet.2017.05.072

•Reductive coupling reaction of benzylic gem-dibromide by Cu/polyamine is achieved.•E-stilbene derivatives were obtained with high yield.•The method is well tolerated to different functional groups.•It provides a short pathway to synthesize symmetrical and asymmetrical E-stilbene.Stereoselective reductive coupling reaction of benzylic gem-dibromide promoted by Cu/polyamine produces E-stilbene derivatives with high yield under mild conditions. It provides a short pathway to synthesize symmetrical and asymmetrical E-stilbene derivatives using cheap reagents and alkenyl-free starting material together with easy workup.Download high-res image (37KB)Download full-size image

Polyacrylates networks synthesized by endlinking of 3-armed precursor via radical addition coupling reaction

Co-reporter:Junmin Gao and Qi Wang

RSC Advances 2016 vol. 6(Issue 66) pp:61615-61619

Publication Date(Web):22 Jun 2016

DOI:10.1039/C6RA10703F

We propose a strategy of synthesis of well-defined polyacrylate networks with cleavable branch units by endlinking of 3-armed prepolymer via radical addition coupling reaction with alkene. Via decrosslinking, cleavage at the branch units, the polymer network can be transformed to linear chains, which can be analyzed by normal methods. The length between the branch units, the distribution of the branch units and the fraction of the dangling chains of the network together with the extent of reaction are directly analyzed, which give detailed description of the polymer network. The method can be applied to prepare amphiphilic conetwork containing tert-butyl acrylate and acrylic acid units.

Radical coupling polymerization (RCP) for synthesis of various polymers

Co-reporter:Zhe Liu and Qi Wang

RSC Advances 2016 vol. 6(Issue 46) pp:39568-39572

Publication Date(Web):04 Apr 2016

DOI:10.1039/C6RA02669A

A general polymerization method is reported, which involves a direct radical coupling reaction of in situ formed benzyl-type biradicals from dibromide in the presence of a Cu(0)/ligand. The radical coupling polymerization can be employed to synthesize polyarene, polyester, polyether and polysulfone under mild conditions and within a short time.

Radical addition-coupling polymerization (RACP) of various benzyl-type biradical toward periodic polymers

Co-reporter:Zhe Liu, Qi Wang

Polymer 2016 Volume 94() pp:14-18

Publication Date(Web):28 June 2016

DOI:10.1016/j.polymer.2016.04.057

•Periodic polymers with different repeating sequences, such as [AX], [AAX] and [ABAX], are synthesized.•Strict control on the sequence of the repeating unit is realized by selection of proper polymerization condition.•Different functional groups, such as benzenic ring, ester, sulfone, ether and NO groups, are incorporated in the polymers.Periodic polymers with different repeating sequences, such as [AX], [AAX] and [ABAX], were synthesized by radical addition-coupling polymerization (RACP) of bifunctional monomers with benzyl bromide/α-methyl benzyl bromide groups and 2-methyl-2-nitrosopropane in the presence of Cu(0)/ligand. By selection of proper ligand and polymerization condition, the defects derived from self-coupling of benzyl-type radicals were eliminated, which results in strict control on the repeating sequence.Periodic polymers with different repeating units were synthesized by radical addition-coupling polymerization (RACP) of bifunctional monomers with benzyl bromide/α-methyl benzyl bromide groups and 2-methyl-2-nitrosopropane in the presence of Cu(0)/ligand.

Characterization of polymer network by combination of tailored synthesis and direct analysis of its decrosslinked components

Co-reporter:Chenglin Li, Qi Wang

Polymer 2016 Volume 99() pp:594-597

Publication Date(Web):2 September 2016

DOI:10.1016/j.polymer.2016.07.064

•Decrosslinkable polymer networks are synthesized by radical coupling reaction of 3-armed polystyrene with cleavable core.•The distribution of the branch unit and the fraction of the dangling chain of polymer gel can be directly measured.•The extent of reaction for sol, gel and the whole can be obtained by direct measurement.We propose a strategy of combination of tailored synthesis and direct analysis of decrosslinked components of the network, which is applicable to quantitative characterization of polymer network. The well-defined polymer networks with cleavable branch units were synthesized by endlinking of 3-armed prepolymer. Via decrosslinking, cleavage at the branch units, the polymer network can be transformed to linear chains, which can be analyzed by normal methods. The length between the branch units, the distribution of the branch units and the fraction of the dangling chains of the network together with the extent of reaction are directly analyzed, which give detailed description of the polymer network.Via decrosslinking, cleavage at the branch units, the polymer network can be transformed to linear chains, which can be fully analyzed by normal methods. The length between the branch unit, the distribution of the branch unit, the fraction of the dangling chain of the network together with the extent of the reaction are directly measured, which give the detailed description of the polymer network structure.

Aqueous radical addition-coupling polymerization using a nitroso benzene/cyclodextrin complex for the synthesis of a hydrophilic periodic polymer

Co-reporter:Fangqi Tao and Qi Wang

RSC Advances 2015 vol. 5(Issue 57) pp:46007-46010

Publication Date(Web):08 May 2015

DOI:10.1039/C5RA02371H

A hydrophilic periodic polymer possessing a [ABxAC]n (A = ester, B = ethylene oxide, C = N–O) repeating sequence was synthesized by aqueous radical addition-coupling polymerization using a water-soluble inclusion complex of nitrosobenzene and Me2-β-cyclodextrin together with poly(ethylene glycol)bis(α-bromoisobutyrate) in the presence of Cu/ligand.

Aqueous radical addition-coupling polymerization for the synthesis of hydrophilic periodic polymer

Co-reporter:Fangqi Tao, Junjie Li and Qi Wang

RSC Advances 2014 vol. 4(Issue 95) pp:53253-53256

Publication Date(Web):01 Oct 2014

DOI:10.1039/C4RA06400C

A hydrophilic polymer possessing a [ABxAC]n (A = ester, B = ethylene oxide, C = N–O) repeating sequence was synthesized by an aqueous radical addition-coupling polymerization using water-soluble dibromide and a nitroso compound in the presence of a CuBr/ligand. This opens up a new pathway to synthesize water-soluble periodic polymers with a regular sequence.

Radical addition-coupling polymerization with various nitroso compounds

Co-reporter:Junjie Li

Journal of Polymer Science Part A: Polymer Chemistry 2014 Volume 52( Issue 6) pp:810-815

Publication Date(Web):

DOI:10.1002/pola.27061

ABSTRACT

Four nitroso esters were prepared by oxidation of 4,4-dimethyl dihydro-1,3-oxazine or 4,4-dimethyl-2-oxazoline with two equiv of m-chloroperoxybenzoic acid. All of them can be applied in radical addition-coupling polymerization to produce periodic polymer together with introduction of ester group at side chain. Compared with 2-methyl-2-nitrosopropane, 2-nitroso-2-methyl-4-acetoxypentane and 2-methyl-2-nitrosopropyl hexanoate present good stability at high temperature up to 70 °C and can result polymer with high molecular weight. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 810–815

Block copolymers prepared by polymeric radical addition cross-coupling reaction to different double bonds

Co-reporter:Chengyu Zhang

Journal of Polymer Science Part A: Polymer Chemistry 2013 Volume 51( Issue 13) pp:2817-2823

Publication Date(Web):

DOI:10.1002/pola.26669

ABSTRACT

We present an efficient method for synthesis of block copolymer by radical addition cross-coupling reaction between two different polymeric radicals and different double bonds. Two different monobromo polymers (P₁-Br and P₂-Br) were reacted with Cu(0)/N,N,N′,N″,N″-pentamethyldiethylenetriamine in the presence of ethyl dithiobenzoate or 1,1-diphenylethylene (X) and the block copolymer (P₁-X-P₂) can be obtained with high efficiency, which cannot be prepared by normal atom transfer radical coupling of mixture of P₁-Br and P₂-Br. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2817–2823.

Thermodegradable multisegmented polymer synthesized by consecutive radical addition-coupling reaction of ,-macrobiradicals and dithioester

Co-reporter:Qinqin Zhu

Journal of Polymer Science Part A: Polymer Chemistry 2012 Volume 50( Issue 10) pp:2029-2036

Publication Date(Web):

DOI:10.1002/pola.25977

Abstract

A consecutive radical addition-coupling reaction involving dithioester is applied to produce thermodegradable multisegmented polymer using α,ω-dibromo polymer as precursor. The macroradical generated by single electron transfer process promoted by Cu/ligand from α,ω-dibromo polymer can efficiently add to ethyl dithiobenzoate, which results intermediate adduct radical. The in situ formed adduct radical immediately undergoes crosscoupling reaction with macroradical, generating segmented polymer bridged with CS bond. The consecutive radical addition-coupling reaction generates multisegmented polymer linked by CS bond following step-growth mechanism. The multisegmented polymer can be thermodegraded in the presence of hydrogen atom donor or air. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Step-Growth Radical Addition-Coupling Polymerization (RACP) for Synthesis of Alternating Copolymers

Co-reporter:Chengyu Zhang

Macromolecular Rapid Communications 2011 Volume 32( Issue 15) pp:1180-1184

Publication Date(Web):

DOI:10.1002/marc.201100208

Degradable multisegmented polymers synthesized by consecutive radical addition-coupling reaction of ,-macrobiradicals and nitroso compound

Co-reporter:Chengyu Zhang

Journal of Polymer Science Part A: Polymer Chemistry 2011 Volume 49( Issue 3) pp:612-618

Publication Date(Web):

DOI:10.1002/pola.24469

Abstract

A consecutive radical addition-coupling reaction induced by spin-trapping agent is applied to produce degradable multisegmented polymer using α,ω-dibromo polymer as a precursor. The macroradical generated by single electron transfer process catalyzed by Cu/PMDETA from α,ω-dibromo polymer can be efficiently captured by 2-methyl-2-nitrosopropane (MNP), which results in nitroxide radical. The in situ formed nitroxide radical immediately undergoes cross-coupling reaction with polymeric radical, generating block polymer bridged with alkoxyamine moiety. The consecutive radical addition-coupling reaction generates multisegmented polymer via step-growth mechanism. Different multisegmented polymers have been prepared from α,ω-dibromo-PS, PtBA, and PtBA-PS-PtBA. The block number of multisegmented polymers can be tailored by varying the feed ratio of α,ω-dibromo precursor to MNP. The multisegmented polymer can be degraded in the presence of hydrogen atom donor or air, and the molecular weight distribution transformed back into shape of its original precursor as it is conjugated by alkoxyamine moieties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Radical Addition-Coupling Polymerization (RACP) toward Periodic Copolymers

Co-reporter:Chengyu Zhang, Jun Ling, and Qi Wang

Macromolecules 2011 Volume 44(Issue 22) pp:8739-8743

Publication Date(Web):October 28, 2011

DOI:10.1021/ma201843n

We synthesize periodic copolymers possessing [ABAC], [ABCD], and [ABCDBCAD] repeating structure by radical addition-coupling polymerization (RACP) based on the reaction between α,ω-biradicals derived from α,α′-dibromo compound and 2-methyl-2-nitrosopropane.

One-pot synthesis of well-defined multiblock polymer: Combination of ATRP and RAFT polymerization involving cyclic trithiocarbonate

Co-reporter:Yusong Wu

Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 11) pp:2425-2429

Publication Date(Web):

DOI:10.1002/pola.24012

Abstract

Multiblock polymers were prepared by combination of ATRP (CuBr/tris[(2-pyridyl)methyl]amine) and RAFT polymerization involving cyclic trithiocarbonate (CTTC). In the combined polymerization system, the ATRP was introduced as constant radical source, CTTC underwent ring-opening polymerization, and the incorporated trithiocarbonate moieties derived from CTTCs performed as RAFT agent. Through the integrated process, multiblock polymers containing predictable average block number together with controlled molecular weight of the blocks were prepared by one-pot polymerization. The average block number of polymer was controlled by concentration ratio of CTTC to alkyl halide in ARTP, and the molecular weight of block were well regulated by concentration of CTTC and monomer conversion. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2425–2429, 2010

Selective activation of metallic center in heterobinuclear cobalt and nickel complex in ethylene polymerization

Co-reporter:Tianxu Sun, Qi Wang, Zhiqiang Fan

Polymer 2010 Volume 51(Issue 14) pp:3091-3098

Publication Date(Web):24 June 2010

DOI:10.1016/j.polymer.2010.04.050

Heterobinuclear cobalt and nickel complex {2-[2,6-R2–C6H3NC(CH3)–(CH3)CN–(3,5-R2′)C6H2–CH2–(3′,5′-R2)C6H2NC(CH3)]-6-[2,6-R2–C6H3NC(CH3)] pyridine}CoCl2NiBr2 (R = isopropyl) (N5CoNi) was prepared by reaction of pentadentate nitrogen ligand containing 2,6-bis(imino)-pyridine and α-diimine moieties with CoCl2 and NiBr2(DME) in turn. The complex was applied as catalyst for ethylene polymerization activated by AlEt3, MMAO and AlEt3/[PhMe2NH] [B(C6F5)4] respectively. The performance of the heterobinuclear complex in ethylene polymerization was compared with corresponding mononuclear complexes (α-diimine nickel bromide and 2,6-bis(imino)-pyridine cobalt chloride) and their equivalent mixture (binary complexes). When the complex N5CoNi was activated by AlEt3 or MMAO, its ethylene polymerization activity was lower than its control, the binary complexes. Both heterobinuclear complex and binary complex produced PE with bimodal molecular weight distribution. The amount of high-molecular-weight polyethylene produced by nickel center of N5CoNi was less than the binary complexes, which reveals that productivity of nickel center of N5CoNi is selectively suppressed. When the heterobinuclear complex N5CoNi is activated by AlEt3/[PhMe2NH][B(C6F5)4], the relative productivity of nickel center increased, although the total activity of catalyst decreased compared with AlEt3 as cocatalyst. With respect to AlEt3, [PhMe2NH][B(C6F5)4] can preferably activate nickel center of heterobinuclear complex. The results suggest that metal site in the heterobinuclear complex is selectively activated by cocatalyst.