Rheological properties of HyperMacs—long‐chain branched analogues of hyperbranched polymers |
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| Authors: | Jonathan M Dodds Edoardo De Luca Lian R Hutchings Nigel Clarke |
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| Institution: | 1. IRC in Polymer Science and Technology, Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom;2. IRC in Polymer Science and Technology, Department of Chemistry, Durham University, Durham DH1 3LE, United KingdomIRC in Polymer Science and Technology, Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom |
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| Abstract: | HyperMacs are long chain branched analogues of hyperbranched polymers, differing only in the sense that they have polymer chains, rather than monomers between branch points. Although the building blocks for HyperMacs and AB2 macromonomers can be well defined in terms of molecular weight and polydispersity, the nature of the coupling strategy adopted for the synthesis of the HyperMacs results in branched polymers with a distribution of molecular weights and architectures. Melt rheology showed polystyrene HyperMacs to be thermorheologically simple, obeying William–Landel–Ferry behavior. Zero shear viscosities of the polymers were shown to increase with average molecular weight and the melts display shear‐thinning behavior. HyperMacs showed little evidence for relaxation by reptation and the rheological behavior agreed well with the Cayley tree model for hierarchical relaxation in tube models of branched polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2762–2769, 2007 |
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| Keywords: | anionic polymerization branched dendritic hyperbranched rheology |
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