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Shape recovery and irrecoverable strain control in polyurethane shape-memory polymer

2008; Taylor & Francis; Volume: 9; Issue: 1 Linguagem: Inglês

10.1088/1468-6996/9/1/015009

1878-5514

Hisaaki TOBUSHI, S. Hayashi, Kazumasa Hoshio, Y. Ejiri,

Polymer composites and self-healing

In shape-memory polymers, large strain can be fixed at a low temperature and thereafter recovered at a high temperature. If the shape-memory polymer is held at a high temperature for a long time, the irrecoverable strain can attain a new intermediate shape between the shape under the maximum stress and the primary shape. Irrecoverable strain control can be applied to the fabrication of a shape-memory polymer element with a complex shape in a simple method. In the present study, the influence of the strain-holding conditions on the shape recovery and the irrecoverable strain control in polyurethane shape-memory polymer is investigated by tension test of a film and three-point bending test of a sheet. The higher the shape-holding temperature and the longer the shape-holding time, the higher the irrecoverable strain rate. The equation that expresses the characteristics of the irrecoverable strain control is formulated.