Stress-Strain Behavior of Shape Memory Polymers by 1WE Method: Application to Tecoflex® |
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Authors: | Christina Schmidt A M Sarwaruddin Chowdhury? Klaus Neuking Gunther Eggeler |
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Institution: | Institute of Materials, Facultit?t für Mechanical Engineering , Ruhr-Universitat Bochum (RUB) , Bochum, Germany |
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Abstract: | Thermomechanical cycles including programming, cooling, unloading and heating to trigger the 1WE were examined for a shape memory polymer (SMP), Tecoflex® (TFX EG-72D). Cycles were performed at 60°C with 50% and 225% strains and the recovery time of 10 min. Strains evolving with time were estimated during the thermomechanical treatments for the total 44 cycles using 50% strains and the total 50 cycles using 225% strains. Recovery ratios for 50% strains and 225% were also estimated. It turns out that programming, cooling, unloading and heating to trigger the 1WE causes an increase of irreversible strain and is associated with a corresponding decrease of the intensity of the 1WE in particular during the first thermomechanical cycles. In parallel scanning electron microscopic study using secondary electron imaging shows a very slight wavy surface structure evolved during cycling. |
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Keywords: | Shape memory polymers Tecoflex® thermomechanical cycles stress and strain |
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