Sequence-Controlled Polymers via Simultaneous Living Anionic Copolymerization of Competing Monomers

Self Cite

4‐Styrenesulfonyl‐(2‐methyl)aziridine (StMAz), the first orthogonal aziridine monomer, for both anionic ring‐opening and radical polymerization is presented. Both polymerization pathways are accessible without using protective groups. Aza‐anionic ring‐opening polymerization (A‐AROP) of StMAz and other methyl‐aziridine derivatives provide multifunctional polyaziridines. Molecular weights between 3000 and 13 000 g mol−1 are obtained with low molecular weight dispersities (Ð = 1.1). The amount of vinyl groups in linear polyaziridines from A‐AROP depends on the monomer/comonomer ratio. The vinyl groups of P(StMAz)‐ homo‐ or copolymers are entirely convertible by thiol‐ene addition. This allows modification with multiple functional groups. Free radical polymerization of StMAz leads to polyalkylenes with aziridine side groups, which are known to be efficiently addressable via nucleophiles. Polysulfonamides still belong to a rather new class of polymers accessible by anionic polymerization. Enlarging the scope of postpolymerization modifications on polyaziridines/‐sulfonamides is important for further macromolecular architectures. The aziridine and the vinyl group are combined to develop the first orthogonal monomer for aza‐anionic polymerization and radical polymerization.

Section: Introductionsupporting

confidence: 67%

Section: Resultsmentioning

confidence: 98%

4‐Styrenesulfonyl‐(2‐methyl)aziridine: The First Bivalent Aziridine‐Monomer for Anionic and Radical Polymerization

Gleede

Rieger

Homann-Müller

et al. 2017

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“…We combined the monomers 3‐VCA, styrene, and 4‐VCA with the strongest expected gradients for a 1 H‐NMR copolymerization kinetics experiment (Scheme ). Copolymerization kinetics of multiple monomers has only been rarely reported and is entirely novel for carbanionic terpolymerization …”

Section: Resultsmentioning

confidence: 99%

Capitalizing on Protecting Groups to Influence Vinyl Catechol Monomer Reactivity and Monomer Gradient in Carbanionic Copolymerization

Leibig

Lange

Birke

et al. 2017

Several vinyl catechol‐based monomers with systematically varied acetal protecting groups suitable for carbanionic polymerization are introduced. All monomers are based on the 4‐vinyl benzodioxole or 5‐vinyl benzodioxole structure and differ in the nature of the protecting group for the catechol functionalities. Different symmetric ketones are used for the protection of the diol functionality. Polymers with average molecular weight from 2500 to 25 000 g mol−1 (Mw/Mn < 1.15) are obtained from homopolymerization of the protected monomers. All monomers are examined regarding the influence of the protecting group on the copolymerization behavior with styrene, using in situ 1H NMR kinetic studies. Length and structure of the alkyl chains generally show no influence for all monomers based on 5‐vinyl benzodioxole. In contrast, all monomers with the protecting group in direct vicinity to the propagating vinyl moiety exhibit dependence between monomer reactivity and chain length of the protecting group. A decrease of the monomer reactivity enables control of the gradient in the copolymerization with styrene. Finally, the first terpolymerization kinetics of a carbanionic polymerization in 1H NMR kinetics is presented, combining the monomers 3‐vinyl catechol acetonide, styrene, and 4‐vinyl catechol acetonide, which enables the one‐pot synthesis of double gradient terpolymers.

“…Though DPE derivatives have been widely used to synthesize in‐chain functionalized polymers, how the DPE units are distributed along the polymer chain is still an interesting challenge for polymer chemists who are focused on the field of LAP. For its special characteristic in living anionic copolymerization, we used the timing sample method (which also has been widely utilized to carry out the kinetic study and investigate the change of chemical compositions during LAP) under high vacuum conditions to investigate the sequential distribution of DPE units in a chain. Through the characterization of a series of samples taken with 1 H NMR, size exclusion chromatography (SEC) and MALDI‐TOF‐MS at different times during the copolymerization, the continuous change of composition and molecular weight can be obtained, and the statistical sequence of the DPE units in the chain can be exactly characterized.…”

Section: Sequence Determinationmentioning

confidence: 99%

Sequence Determination and Regulation in the Living Anionic Copolymerization of Styrene and 1,1‐Diphenylethylene (DPE) Derivatives

Han

2016

The living anionic copolymerization of styrene (St) and 1,1‐diphenylethylene (DPE) derivatives were carried out to investigate how the DPE units are distributed along the polymer chain. Based on the combination of timing sample method and exact characterizations, the sequence determination method was established to reveal the sequential distribution of DPE units along the functionalized chains. In the copolymerization of St and DPE‐SiH, when DPE‐SiH was excessively fed, a strictly alternating structure can be prepared. As the feed ratios of S/D increased, a gradient structure was obtained. Additionally, when the substituent structure of the DPE derivatives changed, the sequence structure could be regulated. It has been confirmed in the copolymerization of St and DPE‐SiH/OMe or DPE‐SiH/NMe2, that the electron‐donating group (‐OMe or ‐NMe2) was introduced into DPE‐SiH. Then, the preliminary sequence regulation method was found. Meanwhile the sequence‐determined grafting was investigated, and bottlebrush polymers with sequence‐determined branches were successfully synthesized.