3D printing of thermoplastic polyurethane shape memory polymer

Copyright 2015 by Raytheon Company. Published by CAMX-The Composites and Advanced Materials Expo with permission.Raytheon has developed a thermoplastic polyurethane (TPU) shape memory polymer (SMP) suitable for 3D printing via fused deposition modeling (FDM®). After printing, the final part may be warmed above its glass transition temperature (Tg), packaged into a temporary shape and held until the temperature is lowered below the Tg. The part will retain this temporary packaged shape until subsequently heated to above the Tg whereby, if left unencumbered, it will spontaneously regain its printed shape. In addition to the shape memory effect, the 3D printed material is many times tougher than other 3D printed materials as indicated by elongation to break values. Typical FDM® materials like Ultem 9085 have an elongation to break in the "Z" direction of around 2.6% [1,2]. The 3D printed Raytheon SMP TPU has an elongation to break of around 70% in the "Z" direction or 27 times greater than 3D printed Ultem 9085. Material properties, testing methodology and data are presented.