Thermo-mechanical cyclic tensile test

In the thermo-mechanical cyclic tensile tests, the shape recovery of the segmented polyurethanes occurs at + 20°C. To examine the influence of T on... 

As a type of smart material, precise control of the SME is essential for the application of SMPs. In the thermo-mechanical cychc tensile tests of the segmented polyurethanes, the third loading curve is close to the second loading curve. In other words, the segmented polyurethanes turn completely elastic after the first deformation. This led to enhancing the shape recovery of the segmented polyurethanes by a pre-deformation treatment. In this study, the segmented polyurethanes were extended to 120% of strain on the tensile tester at + 20°C. Afterwards, the specimens were removed from the tensile tester and kept at + 20°C for 15 minutes for shape recoveiy. Then the recovered specimen was viewed as a new sample to perform the thermo-mechanical cyclic tensile tests with 100% of deformation amplitude. 

The segmented polyirrethane without hard domains shows over 90% of shape recovery in the thermo-mechanical cyclic tensile tests with 50% of elongation. This suggests that the molecular interactions can also play the role of physical cross-finks and enable the segmented polyurethane to show the SME under some... 

Thermo-mechanical cyclic tensile tests of the polymers with HSC = 30%. 

Figure 4.16 illirstrates the thermo-mechanical cyclic tensile tests of the IPDl-based T -SMPUUs from which the shape fixity and shape recovery of the polymers can be calculated via Eqs [3.1] and [3.2]. As shown in Fig. 4.16(a),... 

Shape memory properties of T-type high performance shape memory polyurethane thermo-mechanical cyclic tensile tests... 

The cyclic strain-stress curves of fiber obtained by thermo-mechanical cyclic tensile testing are shown in Fig. 9.14. The fiber has a fixity ratio of more than 85.8% and a recovery ratio of more than 95.4%. The detailed shape fixity ratios and recovery ratios are recorded in Table 9.3. At 60°C, in the first cycle, the maximum stress at full elongation is 0.07 cN/dtex. 

The shape memory effect can be determined quantitatively by cyclic thermo-mechanical tests. These measurements are performed in a tensile tester equipped with a thermo-chamber. At a temperature above a bone-shaped... 

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