Organ, S.J.; Li, J.; Terry, A.E.; Hobbs, J.K. and Barham, P.J.
|DOI (Digital Object Identifier) Link:||http://dx.doi.org/10.1016/j.polymer.2004.10.035|
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Synchrotron X-ray radiation has been used in situ to follow the crystallization of a hydroxybutyrate oligomer containing 32 repeat units from dilute solution in propylene carbonate, and to study chain unfolding during heating in oligomers with 24 and 32 repeat units. A discontinuity in growth rate occurs at 36-37˚C for the 32-mer: crystals grown below this temperature contain folded chains, which transform during heating through a process of partial dissolution and re-crystallization to form extended chain crystals. Crystals grown above the transition temperature contain extended chains that do not rearrange during heating. A similar change happens in the 24-mer between 35 and 40˚C. Thermal expansion in the (110) lattice direction (the fold direction) was in the range 5.3 +/- 0.3 x 10-5 nm degreesC<sup-1</sup>, with an additional discontinuous increase in 0.001 nm accompanying chain unfolding.
|Item Type:||Journal Article|
|Copyright Holders:||2004 Elsevier Ltd.|
|Keywords:||hydroxybutyrate oligomers; WAXS; crystallization from solution|
|Academic Unit/Department:||Mathematics, Computing and Technology > Engineering & Innovation
Mathematics, Computing and Technology
|Depositing User:||Sally Organ|
|Date Deposited:||13 Jun 2006|
|Last Modified:||14 Jan 2016 15:48|
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