|About this Abstract
||2020 TMS Annual Meeting & Exhibition
||Characterization of Minerals, Metals and Materials
||How Small Molecules Can Trigger the One-way Effect in Shape Memory Polymers
||Axel Marquardt, Klaus Neuking, Gunther Eggeler
|On-Site Speaker (Planned)
Programming of shape memory polymers (SMPs) is associated with large deformations of the polymeric chains. This deformation can be stored and later recovered by the application of an appropriate trigger. It is well known that an increase of temperature triggers the one-way effect (1WE). It is less well appreciated that the 1WE can also be triggered chemically. Here, this second phenomenon was investigated. The 1WE is triggered when small molecules diffuse into a polyurethane type SMP. The recovery kinetics was determined by using a special imaging technique with special emphasis on the recovery ratio (the ability of a programmed polymer to recover its initial shape). It was found that a small Hansen-solubility-parameter of the polymer/trigger-molecule system result in lower recovery ratios. The recovery process was modeled using a series of simple rheological elements to identify three underlying mechanisms: ideal shape recovery, accumulation of irreversible strain, and swelling.