Applicability of Frozen Gels from Ultra High Molecular Weight Polyethylene and Paraffin Waxes as Shape Persistent Solid/Liquid Phase Change Materials
✍ Scribed by Uwe Beginn
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 147 KB
- Volume
- 288
- Category
- Article
- ISSN
- 1438-7492
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✦ Synopsis
Abstract
Ultra high molecular weight polyethylene (UHMW‐PE) physically gels molten paraffin waxes (PW) at concentrations exceeding 0.5 wt.‐%. In the composites the paraffin wax crystallises without destruction of the UHME‐PE gel network. Above the melting transition of the paraffin compound the capillary forces prevent the liquid wax from free flow. The composites can be processed by melt extrusion, and injection moulding above the melting temperature of the gel at 116 °C. The thermal and mechanical properties of these UHMW‐PE/paraffin composites have been characterised regarding their applicability as shape persistent phase change materials (PCM). The UHMW‐PE/PW gels can store, and release enthalpies up to 200 J/g at the melting temperature of the PW. In the gel state the liquid alkane can leave the gel when in direct contact to porous materials, and the gels mechanical strength are lower than that of standard polymers. These drawbacks are proposed to overcome by formation of PCM/polymer, or PCM/metal laminates.
Schematic cross section of a proposed PCM laminate consisting of a polymer top‐ and bottom layer enclosing the UHMW‐PE/paraffin gel.
magnified imageSchematic cross section of a proposed PCM laminate consisting of a polymer top‐ and bottom layer enclosing the UHMW‐PE/paraffin gel.