Experimental investigation on the thermo-mechanical deformation of thermo-induced shape memory polyurethane. (10th December 2021)

• Record Type: Journal Article
• Authors: Li, Jian; Liang, Zhihong; Zhang, Xuelian; Kan, Qianhua
• Is Part Of: Polymer. Volume 237(2021)
• Publication Date: 2021-12-10
• Subjects: Shape memory polyurethane -- Thermo-mechanical deformation history -- Cyclic shape memory effect -- Internal stress -- Rate dependence; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2021.124337
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: The influences of loading conditions on the shape memory effect (SME) of thermo-induced shape memory polyurethane (TSMPU) are investigated by series of thermo-mechanical deformation experiments. The variables related to mechanical responses and the strain contours are extracted to analyze the SME. It is shown that the recovery ratio gradually decreases and the residual strain gradually accumulates with the increase of number of cycles. Then, the internal stress is obtained from the experimental results under different deformation histories. It is unexpectedly found that there is a linear relationship between the internal stress and recovery ratio under the same peak strain with different strain rates and number of cycles. Meanwhile, the formation and release of internal stress as the deformation mechanism can reasonably reflect the influence of deformation history on the SME. The experimental results are useful to deepen the understanding of SME and establish a constitutive model considering the thermo-mechanical deformation history of TSMPU. Graphical abstract: Illustration of deformation mechanism of SME: (a) the initial shape at θ h ; (b) the deformation state at θ h ; (c) the deformation state after cooling; (d) the recovery state after reheating. Image 1 Highlights: The cyclic thermo-mechanical deformation behaviors of shape memory polyurethane are investigated. The cyclic shape memory effect is analyzed by monitoring the evolution of strain field. The influence of thermo-mechanical deformation history on the shape memory effect is revealed. The linear relationship between internal stress and recovery ratio can be used to explain the shape memory effect.