The research objective of this Grant Opportunity for Academic Liaison with Industry (GOALI) project is to elucidate the mechanisms controlling the performance of shape memory polymers during mechanical activation. Amorphous shape memory polymers can be programmed to store a temporary shape by applying deformation and cooling below the glass transition temperature. The material recovers the permanent shape when reheated above the transition temperature. The polymer structure can be tailored to meet a broad range of mechanical and biological requirements. This makes them attractive for applications in the biomedical device industry; yet they have not gained wider acceptance because of their slow recovery times. In mechanical activation, mechanical work is applied in addition to temperature to accelerate shape recovery. The research will investigate the importance of two mechanisms, molecular orientation and structural relaxation, on the force requirements for mechanical activation. The effect of shape memory programming conditions and physical aging on mechanical behavior will be measured. Constitutive models will be developed to investigate the effect of material properties and temperature and loading conditions on mechanical activation.
The research will enable the development of more precise programming and more efficient manufacturing strategies for mechanically activated devices. The developed models will help to characterize the safety and performance of these devices throughout their intended shelf life, which can lead to a wider acceptance in the biomedical device industry. Student researchers will gain industry experience through summer internships at a leading company for shape memory polymer medical devices. The research will be integrated into courses to include the mechanics of smart polymers.