Synthesis of water-soluble homo- and block-copolymers by RAFT polymerization under γ-irradiation in aqueous media

Millard, Pierre-Eric; Barner, Leonie; Reinhardt, Jürgen; Buchmeiser, Michael R.; Barner‐Kowollik, Christopher; Müller, Axel H. E.

doi:10.1016/j.polymer.2010.07.017

Cited by 41 publications

(26 citation statements)

References 85 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…polymerisation techniques in contrast to the demanding ionic polymerisation of gaseous ethylene oxide. Furthermore, DMA is known to have a high rate of propagation 53,54 thus fulfilling one of the conditions postulated for an efficient production of star polymers.…”

Section: C12-ctamentioning

confidence: 99%

One-step RAFT synthesis of well-defined amphiphilic star polymers and their self-assembly in aqueous solution

et al. 2012

View full text Add to dashboard Cite

Multifunctional chain transfer agents for RAFT polymerisation were designed for the one-step synthesis of amphiphilic star polymers. Thus, hydrophobically end-capped 3-and 4-arm star polymers, as well as linear ones for reference, were made of the hydrophilic monomer N,N-dimethylacrylamide (DMA) in high yield with molar masses up to 150 000 g mol À1, narrow molar mass distribution (PDI # 1.2) and high end group functionality ($90%). The associative telechelic polymers form transient networks of interconnected aggregates in aqueous solution, thus acting as efficient viscosity enhancers and rheology modifiers, eventually forming hydrogels. The combination of dynamic light scattering (DLS), small angle neutron scattering (SANS) and rheology experiments revealed that several molecular parameters control the structure and therefore the physical properties of the aggregates. In addition to the size of the hydrophilic block (maximum length for connection) and the length of the hydrophobic alkyl chain ends (stickiness), the number of arms (functionality) proved to be a key parameter.

show abstract

Section: C12-ctamentioning

confidence: 99%

One-step RAFT synthesis of well-defined amphiphilic star polymers and their self-assembly in aqueous solution

et al. 2012

View full text Add to dashboard Cite

show abstract

“…An appealing solution to the problem is the use of living radical polymerization techniques, which have offered the same control over molecular weight as well as low polydispersity for polymers. In particular, reversible addition–fragmentation chain transfer (RAFT) polymerization is an attractive approach for making well‐defined polymers because of its applicability to a wide range of monomers, suitability for a broad range of functional groups, and tolerance to various solvents . Therefore, it was postulated that the use of RAFT polymerization would be an ideal methodology for the preparation of a wide variety of polymers that could be used for the fabrication of gels.…”

Section: Introductionmentioning

confidence: 99%

Phenylboronate-diol crosslinked polymer/SWCNT hybrid gels with reversible sol-gel transition

Liu

Chen

et al. 2013

Polym. Adv. Technol.

View full text Add to dashboard Cite

This work demonstrates the successful incorporation of functionalized single‐walled carbon nanotubes (f‐SWCNTs) into the phenylboronate‐diol crosslinked polymer gel to create a hybrid system with reversible sol–gel transition. The phenylboronic acid‐containing and diol‐containing polymers were first separately prepared by the reversible addition–fragmentation chain transfer polymerization. Covalent functionalization of single‐walled carbon nanotubes (SWCNTs) with an azide‐derivatized, diol‐containing polymer was then accomplished by a nitrene addition reaction. Subsequently, the hybrid gels were prepared by crosslinking the mixture of f‐SWCNTs and diol‐containing polymer with the phenylboronic acid‐containing polymer. The hybrid gel has been characterized by scanning electron microscopy (SEM) and rheological analysis. The SEM measurement demonstrated a homogeneous dispersion of f‐SWCNTs within the gel matrices. Rheological experiments also demonstrated that the hybrid gel exhibited storage moduli significantly higher than those of the native gel obtained from the phenylboronic acid‐containing and diol‐containing polymers. The hybrid gel can be switched into their starting polymer (f‐SWCNTs) solutions by adjusting the pH of the system. Moreover, the hybrid gel revealed a self‐healing property that occurred autonomously without any outside intervention. By employing this dynamic character, it is possible to regenerate the used gel, and thus, it has the potential to perform in a range of dynamic or bioresponsive applications Copyright © 2013 John Wiley & Sons, Ltd.

show abstract

“…5,6 Further benefits can arise from conducting polymerisations at room temperature; this has been demonstrated for the synthesis of multiblock copolymers and ultra-high molecular weight copolymers initiated by either ϒ-irradiation or redox methods. [7][8][9] Recently, Sumerlin and coworkers demonstrated the preparation of ultra-high molecular weight poly(N,N-dimethylacrylamide) by photoinitiated RAFT polymerisation in aqueous solution at mild temperature. 10 Gel permeation chromatography (GPC) is the technique to characterise and analyse the average molecular weight and the molecular weight dispersity of synthesised polymers.…”

Section: Introductionmentioning

confidence: 99%

“…Sodium azide is often added to aqueous GPC systems as a biocide and has been used by various research groups for analysing RAFT polymer samples (at concentrations from 75 to 300 ppm). 7,9,[11][12][13] In previous research, sodium azide has been shown to be an effective nucleophile for removing terminal dithiobenzoate CTA groups from the ends of polymer chains. 14 Analogous to the reaction with primary amines, they demonstrated that a thiol-terminated polymer is formed which can then undergo oxygen-facilitated disulfide coupling.…”

Section: Introductionmentioning

confidence: 99%

Cleavage of macromolecular RAFT chain transfer agents by sodium azide during characterization by aqueous GPC

et al. 2017

View full text Add to dashboard Cite

Accurate and reliable analysis of polymers by GPC is vital in the field of controlled radical polymerisation. Often, water-soluble polymers are analysed by aqueous gel permeation chromatography (GPC) in a solvent containing dilute sodium azide as an anti-microbial agent. Previous reports have shown that sodium azide at high concentration is able to remove terminal CTA groups from polymer chains, producing thiol-terminated polymers.This study demonstrates that GPC sample preparation of RAFT polymers in aqueous solvents containing dilute (200 ppm) sodium azide can cause significant changes in the measured molecular weight distribution. These changes occur within hours of dissolving the polymer sample and are shown to be due to cleavage of the CTA in the polymer chain together with disulfide coupling of the resulting polymeric thiols. The extent to which this occurs is strongly dependent on the CTA attached to the polymer; an almost 10-fold difference in the rate of CTA removal is observed between different RAFT agents. The by-product of the reaction between sodium azide and RAFT polymers is also investigated and shown to be an unstable thiatriazole-functionalised Z group. The thiatriazole then degrades further to form a nitrile-functionalised Z group, N 2 and elemental sulfur.3

show abstract

Synthesis of water-soluble homo- and block-copolymers by RAFT polymerization under γ-irradiation in aqueous media

Cited by 41 publications

References 85 publications

One-step RAFT synthesis of well-defined amphiphilic star polymers and their self-assembly in aqueous solution

One-step RAFT synthesis of well-defined amphiphilic star polymers and their self-assembly in aqueous solution

Phenylboronate-diol crosslinked polymer/SWCNT hybrid gels with reversible sol-gel transition

Cleavage of macromolecular RAFT chain transfer agents by sodium azide during characterization by aqueous GPC

Contact Info

Product

Resources

About