Development of shape memory polyurethane fiber with complete shape recoverability

Abstract

To illustrate the shape memory properties of shape memory polyurethane (SMPU) fiberand the difference of thermal/mechanical properties between SMPU fiber and other variousman-made fibers, series of shape memory polyurethane having various hard segmentcontent were synthesized with the pre-polymerization method and spun with the wetspinning process. Differential scanning calorimetry (DSC), dynamic mechanicalanalysis (DMA), and mechanical testing were conducted to study the particularthermal/mechanical properties of shape memory polyurethane fiber in comparison withother man-made fibers such as nylon6, polyester, Lycra and XLA. In addition, in thepreparation of shape memory polyurethane fiber, the effect of thermal setting temperaturewas systematically investigated by mechanical properties testing, DMA and cyclic tensiletesting, suggesting that the thermal setting temperature has a huge influence on themechanical properties and shape memory property due to the elimination of internal stress.Thermal setting with a higher temperature will give rise to a lower tensile modulus andtenacity and a higher elongation ratio at break. Through employing the optimal thermalsetting treatment, the complete heating responsive recovery in SMPU fiber can beachieved because of the counteracting effect of the irreversible strain and thermalshrinkage.