Recovery characteristic of functionally graded shape memory polymer form

Abstract

Polyurethane shape memory polymers (SMPs) are currently being applied in a various fields. SMP has two characteristics such as shape fixity and shape recovery due to temperature changes. Using these properties, SMP can be obtained large recovery stress under constant strain in heating after deformed by cooling. In this study, using the recovery stress, a functionally graded SMP foam (FGSMPF) was fabricated to develop a novel actuator by stacking SMPFs with different glass transition temperatures. Shape recovery test was conducted and two-step behavior of FGSMPF was investigated.