A thermoplastic polyurethane (TPU) developed by Bayer MaterialScience (BMS, Leverkusen / Germany; www.bayerbms.com) and the Federal Institute for Materials Research and Testing (BAM, Berlin / Germany; www.bam.de) is claimed to demonstrate that plastics can have a memory.

Parts made of the material can be temporarily reshaped and fixed in a shape. When heated to a temperature known as the switching temperature, they “remember” their original shape and return to it virtually unchanged. The newly introduced material, “Desmopan” DP 2795A SMP (shape memory plastics), has a switching temperature of around 40°C.

Jürgen Hättig, head of business development for TPU at BMS, said: “We can imagine applications in areas ranging from mechanical engineering and the automotive, textile, sports and leisure industries to toy manufacturing and aerospace engineering.” Possible applications include the repair of damaged bodywork parts using a hair dryer, remote temperature sensors, artificial muscles, hinges, self-loosening screws, packaging and shrink tubing.

BMS and BAM have recently submitted a patent application for a possible use in the area of functional film tunnels and self-erecting structures. Profiles made of the TPU that have temporarily been brought into a flat shape are fastened to the transparent tunnel film. After the film has been laid on the ground the profiles are heated to the switching temperature and they return to their permanent shape and pop up to form a half-tunnel, lifting the films with them to create mini-greenhouses.

BAM has also used the TPU product to develop labels with engraved and coloured quick response (QR) codes that can only be read if the labels are in their permanent shape, providing an alternative in product and brand protection applications.

BMS said the material is also suitable for food contact applications, has high abrasion resistance, flexibility and good chemical resistance.