Triple-shape memory effect in 3d-printed polymers

Abstract

A triple-shape memory effect represents that polymers can memorize two temporary shapes and show a subsequent recovery from the second temporary shape to the first temporary shape and further to the permanent shape with heating, which provides more design freedom for the applications of shape-memory polymers. In this work, we investigate the shape-memory performance of three polymers produced by a commercial 3D printer. Two polymers with a pure component exhibit distinct glass transition regions spanning 30°C for each material. The copolymer has a broader glass transition region from –4 to 59 °C. The dual-shape memory tests show that the deformation temperature has a limited influence on the two pure poly-mers, while a clear temperature memory effect can be observed in the copolymer. For the copolymer, the recovery region has only a small overlap when deformed at 60 and 20 °C, which allows programming two temporary shapes at these two temperatures. Both uniaxial tension tests and three-dimensional demonstration show that the copolymer exhibits a good triple-shape memory effect.