Reversible plasticity shape memory effect in epoxy/CNT nanocomposites - A theoretical study

Abishera, R.; Ramachandran, V.; Gopal, K.V. Nagendra

doi:10.1016/j.compscitech.2017.01.020

Cited by 28 publications

(13 citation statements)

References 44 publications

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“…To summarize, the principle behind the steps in an RPSM cycle can be explained as follows : When the material is deformed at the glassy state beyond the elastic region, the molecular segments are reorganized which in turn change its configurational entropy (Step i). Below T g the plastic deformation is a rate‐dependent process, so the relaxation time allows some reorientation of the deformed molecular structure where the stress reduces asymptotically to a non‐zero value (Step ii).…”

Section: Resultsmentioning

confidence: 99%

Reversible plasticity shape memory effect in carbon nanotube/epoxy nanocomposites: Shape recovery studies for torsional and bending deformations

Abishera

Ramachandran

Gopal

2018

Polymer Engineering & Sci

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Thermally activated shape memory polymers (SMP) are typically programmed by initially heating the material above the glass transition temperature (Tg), deforming to the desired shape, cooling below Tg and unloading to fix the temporary shape. Though this approach is employed in small‐scale applications, the process of deforming at high temperatures becomes a time, labor, and energy expensive process while applying to large structures (e.g. deployable space structures). The reversible plasticity shape memory (RPSM) property provides an alternate programming approach wherein the material is plastically deformed to a temporary shape at temperatures well below the transition temperature, preferably at room temperature. This paper aims to study the advantages of RPSM programming under bending and torsional deformations in multi‐walled carbon‐nanotube (MWCNT) reinforced epoxy nanocomposites. The samples are characterized for their thermal, morphological, and mechanical properties. The shape recovery behavior under various deformation modes is studied in detail. The effect of deformation level, relaxation time, and thermo‐mechanical cycles are also studied. All samples show excellent shape memory properties under all deformation modes and programming conditions. As a result, it is demonstrated that the RPSM programming can be used as an effective and a simplified alternative to conventional shape memory programming. POLYM. ENG. SCI., 58:E189–E198, 2018. © 2018 Society of Plastics Engineers

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Section: Resultsmentioning

confidence: 99%

Reversible plasticity shape memory effect in carbon nanotube/epoxy nanocomposites: Shape recovery studies for torsional and bending deformations

Abishera

Ramachandran

Gopal

2018

Polymer Engineering & Sci

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“…To model SMP nanocomposites, including carbon nanotube (CNT) nanoparticles, Abishera et al (2017), using the same SLS model, considered structural relaxation and stress relaxation (similar to Chen et al, 2014; Gu et al, 2015a; Nguyen et al, 2008). The developed nanocomposite model was examined both numerically and experimentally in strain recovery step.…”

Section: Modeling Thermo-responsive Smpsmentioning

confidence: 99%

“…However, in this study, we do not attempt to classify SMP material models from a micro- or macro-modeling point of view and simply divide them into the phase transition and viscoelastic points of view. In general, in this approach, while the SME is characterized by parameters such as stored strain and frozen phase volume fraction, these parameters give a non-physical description of the phase transition phenomenon (Abishera et al, 2017; Li and Xu, 2011). In other words, this view does not take into account the microscopic thermo-viscoelastic phenomena occurring during the phase transition (Jackle, 1986).…”

Section: Modeling Thermo-responsive Smpsmentioning

confidence: 99%

A comprehensive review on thermomechanical constitutive models for shape memory polymers

Yarali

Taheri

Baghani

2020

Journal of Intelligent Material Systems and Structures

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Shape memory polymers are a class of smart materials, which are capable of fixing their deformed shapes, and can return to their original shape in reaction to external stimulus such as heat. Also due to their exceptional properties, they are mostly used in four-dimensional printing applications. To model and investigate thermomechanical response of shape memory polymers mathematically, several constitutive equations have been developed over the past two decades. The purpose of this research is to provide an up-to-date review on structures, classifications, applications of shape memory polymers, and constitutive equations of thermally responsive shape memory polymers and their composites. First, a comprehensive review on the properties, structure, and classifications of shape memory polymers is conducted. Then, the proposed models in the literature are presented and discussed, which, particularly, are focused on the phase transition and thermo-viscoelastic approaches for conventional, two-way as well as multi-shape memory polymers. Then, a statistical analysis on constitutive relations of thermally activated shape memory polymers is carried out. Finally, we present a summary and give some concluding remarks, which could be helpful in selection of a suitable shape memory polymer constitutive model under a typical application.

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“…The influence of multi-walls CNTs on the shape memory effect of epoxy nanocomposites was deliberate by Abishera et al [39] as implementation in the selfhealing systems applications under different programming conditions. It was revealed that the changing in the programming conditions obtained an excellent shape memory behavior, as well as, the incorporation of the multi-walls of CNTs has indicated an improvement in the young modulus, strength, recovery speed and shape fixity of epoxy associated with drops in the failure strain.…”

Section: Carbon-based Reinforcementmentioning

confidence: 99%

Future Prospects: Shape Memory Features in Shape Memory Polymers and Their Corresponding Composites

Saud¹,

Majdi²,

Al-Humairi³

et al. 2019

Smart and Functional Soft Materials

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Shape memory polymers and their related composites are formally known as SMPs and SMPCs have been classified as innovative categories of smart materials, in which they affected by a particular stimulus and consequently memorize the original shape. As one of the most vital feature of shape memory characteristics, Shape Memory Effect (SME) that been attracted significant attention from the shape memory researchers and scientists. On the other hands, there are abundant approaches can be implemented to actuate the SMPs and SMPCs deformation, whereby the features of the electro-or thermal response associated with the structural changes are predominant. In this chapter, a particular emphasis on how the incorporation of micro/nano-fillers and particles or fibers do affect in the SMP matrices, which it is intentionally carried out to improve the mechanical properties and their related shape memory features of various types of shape memory polymers. In the summary, the shape memory effect is been sustained to be an intrinsic feature for the SMPs and based on this property, the implementation of the SMPs have covered a wide range of applications according to the required functions and performances.

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Reversible plasticity shape memory effect in epoxy/CNT nanocomposites - A theoretical study

Cited by 28 publications

References 44 publications

Reversible plasticity shape memory effect in carbon nanotube/epoxy nanocomposites: Shape recovery studies for torsional and bending deformations

Reversible plasticity shape memory effect in carbon nanotube/epoxy nanocomposites: Shape recovery studies for torsional and bending deformations

A comprehensive review on thermomechanical constitutive models for shape memory polymers

Future Prospects: Shape Memory Features in Shape Memory Polymers and Their Corresponding Composites

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