Diffusion of a UV-stabiliser in some poly (ester-block-ether) copolymers

Billingham, N C and Lazare, L (2001) Diffusion of a UV-stabiliser in some poly (ester-block-ether) copolymers. Polymer, 42 (23). pp. 9461-9467. ISSN 0032-3861

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The diffusion coefficient, D, of a typical UV-absorbing stabiliser has been measured in a series of poly(ester-block-ether) copolymers (PEBEs) with different fractions of the polyether blocks, by using ultra-violet microscopy to monitor the concentration profile of the additive diffused into the edge of a thin film of polymer over a range of temperatures. For all samples, D shows an Arrhenius dependence on temperature over the range studied. At a given temperature, D increases rapidly with the polyether content, showing a percolation threshold and a marked drop in activation energy at 30 wt% polyether. This is consistent with the view that D is higher in the polyether than in the polyester and that there is a change in morphology at the percolation threshold, from isolated particles of the polyether to a co-continuous morphology with percolation paths of polyether. Comparison with data for the same permeant in polypropylene shows differences, which can be accounted for at least qualitatively by a free-volume argument.

Item Type: Article
Additional Information: This is from work funded by DSM Netherlands. It is the first study of migration of a large (MW = 450) additive in a biphasic polymer, showing the percolation threshold. The results have practical implication in understanding the loss of stabilisers by blooming.
Schools and Departments: School of Life Sciences > Chemistry
Depositing User: Norman Billingham
Date Deposited: 06 Feb 2012 21:20
Last Modified: 30 Mar 2012 09:18
URI: http://sro.sussex.ac.uk/id/eprint/30801
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