| 摘要 |
<p>A method of preparing a morphable (able to undergo a change in form or shape) material comprises applying a non uniform compression to the material. The material may be heated prior to or during, and cooled following, compression. Alternatively, when the material is foam it may be exposed to a solvent prior to compression and dried after compression. The non-uniform compression may involve applying compression to a portion of material and no compression to a further portion. The compressed portion may have a greater cross-section than the uncompressed portion and it may be compressed so that it has the same cross-section. The material may be mechanically activated by application of a tensile load. The material may be expanded PTFE which is auxetic and which retains its shape when compressed such that it exhibits greater auxesis when subjected to a tensile load generally perpendicular to the direction of compression. The material may be thermoplastic, metallic, thermoset or ceramic foam. The non-uniform compression may be applied in a mould. The material may be polyurethane foam. The material may be used on a component of a vehicle, aircraft, boat, spacecraft, impact absorber, filter, packaging or a garment.</p> |
