We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham Research Online
You are in:

Association and relaxation of supra-macromolecular polymers.

Boothroyd, S.C. and Hoyle, D.M. and McLeish, T.C.B. and Munch, E. and Schach, R. and Smith, A.J. and Thompson, R.L. (2019) 'Association and relaxation of supra-macromolecular polymers.', Soft matter., 15 (26). pp. 5296-5307.


This paper describes the structures created by assembling functionalised entangled polymers and the effect these have on the rheology of the material. A polybutadiene (PBd) linear polymer precursor of sufficient molecular weight to be entangled is used. This is end functionalised with the self-associating group 2-ureido-4pyrimidinone (UPy). Interestingly, despite the relatively high molecular weight of the precursor diluting the UPy concentration, the effect on the material’s properties is significant. To characterise the assembled microstructure we present linear rheology, extensional non-linear rheology and small angle X-ray scattering (SAXS). The linear rheology shows that the functionalised PBd assembles into large macro-structures where the terminal relaxation time is up to seven orders of magnitude larger than the precursor. The non-linear rheology shows strain-hardening over a broad range of strain-rates. We then show by both SAXS and modelling of the extensional data that there must exist clusters of UPy associations and hence assembled polymers with branched architecture. By modelling the supra-molecular structure as an effective linear polymer, we show that this would be insufficient in predicting the strain-hardening behaviour at lower extension-rates. Therefore, in this flow regime the strain-hardening is likely to be caused by branching. This is backed up by SAXS measurements which show that UPy clusters larger than pair-pair groups exist.

Item Type:Article
Full text:(AM) Accepted Manuscript
Download PDF
Publisher Web site:
Date accepted:13 June 2019
Date deposited:14 June 2019
Date of first online publication:14 June 2019
Date first made open access:13 June 2020

Save or Share this output

Look up in GoogleScholar