Modeling the Shape-Memory Behavior of Amorphous Polymers
Thursday, September 12, 2013
4:30 pm - 5:30 pm
Fitzpatrick Center Schiciano Auditorium Side A
MRSEC Seminar Series: Prof Thao (Vicky) Nguyen, Assistant Professor, The Johns Hopkins University. Modeling the Shape-Memory Behavior of Amorphous Polymers. The time-dependent mechanisms of the glass transition can be exploited to program large recoverable shape changes in amorphous polymers. These shape memory polymers have enormous potential applications as morphing structures and deployable devices for aerospace and biomedical applications. The shape memory response in polymers is robust and repeatable, but the performance of current shape memory polymer devices are limited by the material's slow response time and small activation force. The shape memory performance is controlled by a combination of many factors, including thermomechanical properties and programming conditions. We developed a constitutive model to predict the shape memory behavior of amorphous networks that features the time-dependent mechanisms of the glass transition, including viscoelasticity, structural relaxation, and solvent effects. This presentation describes the model formulation, experimental characterization for parameter determination, and application of the model to predict the shape memory behavior under a variety of mechanical constraints and temperature conditions as well as the effects of physical aging and solvent absorption.