Agostini, Serena and Hutchings, Lian R. (2013) 'Synthesis and temperature gradient interaction chromatography of model asymmetric star polymers by the "macromonomer" approach.', European polymer journal., 49 (9). pp. 2769-2784.
We describe herein the synthesis and characterisation of a series of asymmetric three arm polystyrene stars via the “macromonomer” approach. The stars have been designed as model polymers to probe branched polymer dynamics and in particular to establish the chain-length of side-arm which precipitates a change in the rheological properties of the resulting polymers from “linear-like” to “star-like”. Thus, a homologous series of three arm stars have been prepared in which the molar mass of two (long) arms are fixed at 90,000 g mol−1 and the molar mass of the remaining (short) arm is varied from below the entanglement molecular weight (Me) to above Me. The arms were prepared by living anionic polymerisation, resulting in well-defined chain lengths with narrow molecular weight distribution. In contrast to the usual chlorosilane coupling approach, the macromonomer approach involves the introduction of reactive chain-end functionalities on each of the arms, either through the use of a functionalised (protected) initiator or a functional end-capping agent, which allows the stars to be constructed by a simple condensation coupling reaction. In this study we will compare the relative efficiency of a Williamson and ‘click’ coupling reaction in producing the stars. Most significantly, although this approach maybe a little more time-consuming than the more common silane coupling reaction, in the present study the “long” arm may be produced in sufficient quantity such that all of the asymmetric stars are produced with long arms of identical molecular weight – the only remaining variable being the molecular weight of the short arm. This will allow for a far more robust interpretation of the resulting characterisation of the dynamic properties. Temperature gradient interaction chromatography was used alongside size exclusion chromatography to characterise the structural dispersity of the resulting stars and establish the degree of structural homogeneity.
|Keywords:||Branched polymer, Temperature gradient interaction chromatography (TGIC), Anionic polymerisation, Macromonomer.|
|Full text:||(AM) Accepted Manuscript|
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|Publisher Web site:||http://dx.doi.org/10.1016/j.eurpolymj.2013.06.021|
|Publisher statement:||NOTICE: this is the author’s version of a work that was accepted for publication in European Polymer Journal. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in European Polymer Journal, 49, 9, 2013, 10.1016/j.eurpolymj.2013.06.021.|
|Date accepted:||No date available|
|Date deposited:||29 July 2014|
|Date of first online publication:||September 2013|
|Date first made open access:||No date available|
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