Recent advance on constitutive models of thermal‐sensitive shape memory polymers

Abstract

Shape memory polymers (SMPs) are a novel class of shape memory materials which can store a deformed (temporary) shape and recover an original (permanent) shape under a shape memory thermomechanical loading-unloading cycle. The deformation mechanisms of SMPs are very complicated, but the SMPs also have a lot of advantages and the widespread application value and prospect. So developing proper constitutive models that describe thermomechanical properties of SMPs and the shape memory effect is very challenging and of great theoretical and application value. Based on the deformation mechanisms and considerable experimental investigations of SMPs, researchers have developed many constitutive models. This article investigates the deformation mechanism and introduces the recent research advance of the constitutive models of thermal-sensitive SMPs. Special emphases are given on the micromechanical constitutive relations in which the deformation is considered being based on the microstructure of the SMPs. Finally, the lack of research and prospects for further research are discussed. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: [1502][1503][1504][1505][1506][1507][1508] 2012

Application of Fractional Calculus Methods to Viscoelastic Response of Amorphous Shape Memory Polymers

“…The thermally activated SMPs are shown to be the most extensively studied due to their variety, simple activated form, large recoverable deformation and rapid response. Constitutive models based on viscoelasticity are one of two kinds of main approaches to model and predict the thermomechanical behaviors of thermally activated SMPs during the past decade [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. These viscoelastic models such as Kelvin and Maxwell-based models are used to describe rate-dependent behaviors of polymers on macroscopic scale and in these models, materials are assumed as a combination of springs, dashpots or frictional elements.…”

Stress memory of a thermoset shape memory polymer

“…In particular, below T g , movements of the polymer segments are restricted. When subsequently heated above T g , the rotation around the segment bonds becomes increasingly unimpeded, and most macromolecules will form compact random coil conformations due to entropic favor, resulting in a recovery to the initial permanent shape …”

“…When subsequently heated above T g , the rotation around the segment bonds becomes increasingly unimpeded, and most macromolecules will form compact random coil conformations due to entropic favor, resulting in a recovery to the initial permanent shape. 12,13 However, in some biomedical and engineering applications, stress recovery usually plays a more important role. For example, when SMP wires are used as sutures, the recovery force by the wire decides the ability to close the wound.…”

Microstructure and shape memory effect of acidic carbon nanotubes reinforced polyvinyl alcohol nanocomposites

“…Shape memory polymers (SMPs) have attracted much attention in recent years due to their potential applications in micromechanical systems and biomedical devices 1–3. Compared with alloys and ceramic materials, SMPs have the ability to store elastic strain energy and recover large strains with quick response when subjected to external stimuli, such as temperature, pH, electric fields, magnetic fields, and solvents 4–6.…”