Modeling the thermo-mechanical behavior and constrained recovery performance of cold-programmed amorphous shape-memory polymers

Dai, Lu; Tian, Chuanshuai; Xiao, Rui

doi:10.1016/j.ijplas.2019.102654

Cited by 90 publications

(35 citation statements)

References 79 publications

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“…From the mechanics of materials point of view, there are at least two parts in a SMP, one is the elastic part, which stores the elastic energy after programming and releases the elastic energy to drive shape recovery, and the other is the transition part, which changes its stiffness according to whether the right stimulus is presented and hold the deformed temporary shape after programming. Depending on the actual working mechanism, the elastic part might be the cross-linked network only, or together with additional contribution from a portion of yet softened transition part during programming [ 14 , 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Vitrimer-Like Shape Memory Polymers: Characterization and Applications in Reshaping and Manufacturing

et al. 2020

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The shape memory effect (SME) refers to the ability of a material to recover its original shape, but only in the presence of a right stimulus. Most polymers, either thermo-plastic or thermoset, can have the SME, although the actual shape memory performance varies according to the exact material and how the material is processed. Vitrimer, which is between thermoset and thermo-plastic, is featured by the reversible cross-linking. Vitrimer-like shape memory polymers (SMPs) combine the vitrimer-like behavior (associated with dissociative covalent adaptable networks) and SME, and can be utilized to achieve many novel functions that are difficult to be realized by conventional polymers. In the first part of this paper, a commercial polymer is used to demonstrate how to characterize the vitrimer-like behavior based on the heating-responsive SME. In the second part, a series of cases are presented to reveal the potential applications of vitrimer-like SMPs and their composites. It is concluded that the vitrimer-like feature not only enables many new ways in reshaping polymers, but also can bring forward new approaches in manufacturing, such as, rapid 3D printing in solid state on space/air/sea missions.

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Section: Introductionmentioning

confidence: 99%

Vitrimer-Like Shape Memory Polymers: Characterization and Applications in Reshaping and Manufacturing

et al. 2020

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“…The strength of intermolecular interaction in polymers can be further affected by the newly formed bonding, which further results in a change in the relaxation responses [ 27 ]. In addition to solvents, some works [ 28 , 29 ] also show that the relaxation spectrum of dry polymers can be changed by mechanical deformation.…”

Section: Resultsmentioning

confidence: 99%

Glass Transition Behavior of Wet Polymers

2021

Materials

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We have performed a systematical investigation on the glass transition behavior of amorphous polymers with different solvent concentrations. Acrylate-based amorphous polymers are synthesized and treated by isopropyl alcohol to obtain specimens with a homogenous solvent distribution. The small strain dynamic mechanical tests are then performed to obtain the glass transition behaviors. The results show that the wet polymers even with a solvent concentration of more than 60 wt.% still exhibit a glass transition behavior, with the glass transition region shifting to lower temperatures with increasing solvent concentrations. A master curve of modulus as a function of frequency can be constructed for all the polymer–solvent systems via the time–temperature superposition principle. The relaxation time and the breadth of the relaxation spectrum are then obtained through fitting the master curve using a fractional Zener model. The results indicate that the breadth of the relaxation spectrum has been greatly expanded in the presence of solvents, which has been rarely reported in the literature. Thus, this work can potentially advance the fundamental understanding of the effects of solvent on the glass transition behaviors of amorphous polymers.

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“…Normally, the viscoelastic models cannot be applied to simulate the shape-memory performance of polymers with the temporary shape programmed below the glass transition region. To overcome this limitation, Dai et al [2020] recently developed a viscoplastic model to describe the constrained recovery performance of cold-programmed SMPs. The model successfully captures the dependence of the recovery stress on programming temperature and strain.…”

Section: -4mentioning

confidence: 99%

Recent Advances of the Constitutive Models of Smart Materials — Hydrogels and Shape Memory Polymers

Huang

Zheng

Liu

et al. 2020

Int. J. Appl. Mechanics

187

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Hydrogels and shape memory polymers (SMPs) possess excellent and interesting properties that may be harnessed for future applications. However, this is not achievable if their mechanical behaviors are not well understood. This paper aims to discuss recent advances of the constitutive models of hydrogels and SMPs, in particular the theories associated with their deformations. On the one hand, constitutive models of six main types of hydrogels are introduced, the categorization of which is defined by the type of stimulus. On the other hand, constitutive models of thermal-induced SMPs are discussed and classified into three main categories, namely, rheological models; phase transition models; and models combining viscoelasticity and phase transition, respectively. Another feature in this paper is a summary of the common hyperelastic models, which can be potentially developed into the constitutive models of hydrogels and SMPs. In addition, the main advantages and disadvantages of these constitutive modes are discussed. In order to provide a compass for researchers involved in the study of mechanics of soft materials, some research gaps and new research directions for hydrogels and SMPs constitutive modes are presented. We hope that this paper can serve as a reference for future hydrogel and SMP studies.

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Modeling the thermo-mechanical behavior and constrained recovery performance of cold-programmed amorphous shape-memory polymers

Cited by 90 publications

References 79 publications

Vitrimer-Like Shape Memory Polymers: Characterization and Applications in Reshaping and Manufacturing

Vitrimer-Like Shape Memory Polymers: Characterization and Applications in Reshaping and Manufacturing

Glass Transition Behavior of Wet Polymers

Recent Advances of the Constitutive Models of Smart Materials — Hydrogels and Shape Memory Polymers

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