Magnetic Field Actuation of Shape Memory Nanocomposites

2010 ◽  
Vol 123-125 ◽  
pp. 999-1002 ◽  
Author(s):  
Atefeh Golbang ◽  
Mehrdad Kokabi
Keyword(s):  
Magnetic Field ◽  
Shape Memory ◽  
Magnetic Particles ◽  
Shape Recovery ◽  
Shape Memory Polymers ◽  
Conventional Heating ◽  
Inductive Heating ◽  
Stimuli Responsive ◽  
Maximum Heat ◽  
Alternative Magnetic Field

Shape memory polymers are stimuli-responsive materials able to adaptively store a temporary (deformed) shape and recover a ‘memorized’ permanent shape under an external stimulus. In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, Tswitch. If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from NdFeB magnetic particles and crosslinked low density polyethylene (XLDPE) shape memory nanocomposite containing 2 wt% nanoclay is introduced. Various amounts of NdFeB particles (5, 15, 40 wt %) were added to the nanocomposite. Electromagnetically triggered shape memory properties of the formed composites were conducted using an alternative magnetic field with a frequency of 9 kHz and strength of 15 kW. The shape recovery of samples was possible by inductive heating and the shape recovery rates comparable to those obtained by conventional heating methods were demonstrated. It was concluded that the maximum heat generation achievable by inductive heating in the alternative magnetic field depends on magnetic particle content. The sample containing 15wt% NdFeB reached a full shape recovery of 25% extension within 6 minutes remaining in the magnetic field.

Novel Behavior in Smart Polymeric Materials: Stress Memory and its Potential Applications

2016 ◽  
Vol 97 ◽  
pp. 93-99
Author(s):  
Jin Lian Hu ◽  
Harishkumar Narayana
Keyword(s):  
Magnetic Field ◽  
Shape Memory ◽  
Smart Materials ◽  
Shape Memory Polymers ◽  
Polymeric Materials ◽  
External Stimulus ◽  
Artificial Muscles ◽  
Recovery Stress ◽  
Stress Memory ◽  
Potential Applications

Materials, structures and systems, responsive to an external stimulus are smart and adaptive to our human demands. Among smart materials, polymers with shape memory effect are at the forefront of research leading to comprehensive publications and wide applications. In this paper, we extend the concept of shape memory polymers to stress memory ones, which have been discovered recently. Like shape memory, stress memory represents a phenomenon where the stress in a polymer can be programmed, stored and retrieved reversibly with an external stimulus such as temperature and magnetic field. Stress memory may be mistaken as the recovery stress which was studied quite broadly. Our further investigation also reveals that stress memory is quite different from recovery stress containing multi-components including elastic and viscoelastic forces in addition to possible memory stress. Stress memory could be used into applications such as sensors, pressure garments, massage devices, electronic skins and artificial muscles. The current revelation of stress memory potentials is emanated from an authentic application of memory fibres, films, and foams in the smart compression devices for the management of chronic and therapeutic disorders.

scholarly journals Water Triggered Shape Memory Materials

2013 ◽  
Vol 3 (1) ◽  
pp. 49-50 ◽  
Author(s):  
Guoguang Niu
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Shape Memory Polymers ◽  
Electrical Current ◽  
Light Illumination ◽  
Poly Ethylene Glycol ◽  
Thermally Induced ◽  
Permanent Shape ◽  
Poly Ethylene ◽  
Novel Strategy

The term "shape memory effect" refers to the ability of a material to be deformed and fixed into a temporary shape, and to recover its original, permanent shape upon an external stimulus (1). Shape memory polymers have attracted much interest because of their unique properties, and applied tremendously in medical area, such as biodegradable sutures, actuators, catheters and smart stents (2, 3). Shape memory usually is a thermally induced process, although it can be activated by light illumination, electrical current, magnetic, or electromagnetic field (4-6). During the process, the materials are heated directly or indirectly above their glass transition temperature (Tg) or the melting temperature (Tm) in order to recover the original shape. Non-thermally induced shape memory polymers eliminate the temperature constrains and enable the manipulation of the shape recovered under ambient temperature (7, 8). Herein, we report a novel strategy of water induced shape memory, in which the formation and dissolution of poly(ethylene glycol) (PEG) crystal is utilized for the fixation and recovery of temporary deformation of hydrophilic polymer. This water-induced shape recovery is less sensitive to temperature, of which 95% deformation is fixed in circumstance and over 75% recovery is reached even at 0 oC.

scholarly journals A Large-Deformation Theory for Thermally-Actuated Shape-Memory Polymers and its Application

2010 ◽  
Author(s):  
Shawn A. Chester ◽  
Vikas Srivastava ◽  
Claudio V. Di Leo ◽  
Lallit Anand
Keyword(s):  
Glass Transition ◽  
Shape Memory ◽  
Deformation Theory ◽  
Shape Recovery ◽  
Large Deformations ◽  
Shape Memory Polymers ◽  
The Body ◽  
Thermally Induced ◽  
Thermally Actuated ◽  
Common Shape

The most common shape-memory polymers are those in which the shape-recovery is thermally-induced. A body made from such a material may be subjected to large deformations at an elevated temperature above its glass transition temperature &Vthgr;g. Cooling the deformed body to a temperature below &Vthgr;g under active kinematical constraints fixes the deformed shape of the body. The original shape of the body may be recovered if the material is heated back to a temperature above &Vthgr;g without the kinematical constraints. This phenomenon is known as the shape-memory effect. If the shape recovery is partially constrained, the material exerts a recovery force and the phenomenon is known as constrained-recovery.

scholarly journals Bio-Based Epoxy Shape-Memory Thermosets from Triglycidyl Phloroglucinol

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 542 ◽  
Author(s):  
David Santiago ◽  
Dailyn Guzmán ◽  
Francesc Ferrando ◽  
Àngels Serra ◽  
Silvia De la Flor
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Memory Performance ◽  
Crosslinking Agent ◽  
Shape Memory Polymers ◽  
Crosslinking Density ◽  
Mechanical Analysis ◽  
Diglycidyl Ether ◽  
Partial Substitution ◽  
Scanning Calorimetry

A series of bio-based epoxy shape-memory thermosetting polymers were synthesized starting from a triglycidyl phloroglucinol (3EPOPh) and trimethylolpropane triglycidyl ether (TPTE) as epoxy monomers and a polyetheramine (JEF) as crosslinking agent. The evolution of the curing process was studied by differential scanning calorimetry (DSC) and the materials obtained were characterized by means of DSC, thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), stress-strain tests, and microindentation. Shape-memory properties were evaluated under free and totally constrained conditions. All results were compared with an industrial epoxy thermoset prepared from standard diglycidyl ether of Bisphenol A (DGEBA). Results revealed that materials prepared from 3EPOPh were more reactive and showed a tighter network with higher crosslinking density and glass transition temperatures than the prepared from DGEBA. The partial substitution of 3EPOPh by TPTE as epoxy comonomer caused an increase in the molecular mobility of the materials but without worsening the thermal stability. The shape-memory polymers (SMPs) prepared from 3EPOPh showed good mechanical properties as well as an excellent shape-memory performance. They showed almost complete shape-recovery and shape-fixation, fast shape-recovery rates, and recovery stress up to 7 MPa. The results obtained in this study allow us to conclude that the triglycidyl phloroglucinol derivative of eugenol is a safe and environmentally friendly alternative to DGEBA for preparing thermosetting shape-memory polymers.

Deployable Process Analysis of Packaged SMP Sandwich Beam

2010 ◽  
Vol 123-125 ◽  
pp. 943-946 ◽  
Author(s):  
Zheng Fa Li ◽  
Zheng Dao Wang
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Sandwich Structure ◽  
Shape Recovery ◽  
Process Analysis ◽  
Sandwich Beam ◽  
Shape Memory Polymers ◽  
Recovery Stress ◽  
Recovery Response

Shape memory polymers own many advantages compared with traditional shape memory alloys or ceramics. In order to improve their shape recovery stress and realize a stable recovery response during the deployable process, the structure of SMP sandwich beam composed of two metallic skin and one SMP core is considered. The recovery behaviors of pure SMP and SMP beams reinforced by one-layer metallic skin are also discussed for comparison. The results confirm that the deployable properties of SMP matrix can be significantly improved by using sandwich structure.

Additive manufacturing of shape memory polymers: effects of print orientation and infill percentage on shape memory recovery properties

2020 ◽  
Vol 26 (9) ◽  
pp. 1593-1602
Author(s):  
Jorge Villacres ◽  
David Nobes ◽  
Cagri Ayranci
Keyword(s):  
Additive Manufacturing ◽  
Shape Memory ◽  
Shape Recovery ◽  
Fused Deposition Modeling ◽  
Large Strain ◽  
Shape Memory Polymers ◽  
Polymeric Materials ◽  
Content Type ◽  
Fused Deposition ◽  
Memory Recovery

Purpose The purpose of this paper is to study the shape memory properties of SMP samples produced through a MEAM process. Fused deposition modeling or, as it will be referred to in this paper, material extrusion additive manufacturing (MEAM) is a technique in which polymeric materials are extruded though a nozzle creating parts via accumulation and joining of different layers. These layers are fused together to build three-dimensional objects. Shape memory polymers (SMP) are stimulus responsive materials, which have the ability to recover their pre-programmed form after being exposed to a large strain. To induce its shape memory recovery movement, an external stimulus such as heat needs to be applied. Design/methodology/approach This project investigates and characterizes the influence of print orientation and infill percentage on shape recovery properties. The analyzed shape recovery properties are shape recovery force, shape recovery speed and time elapsed before activation. To determine whether the analyzed factors produce a significant variation on shape recovery properties, t-tests were performed with a 95% confidence factor between each analyzed level. Findings Results proved that print angle and infill percentage do have a significant impact on recovery properties of the manufactured specimens. Originality/value The manufacturing of SMP objects through a MEAM process has a vast potential for different applications; however, the shape recovery properties of these objects need to be analyzed before any practical use can be developed. These have not been studied as a function of print parameters, which is the focus of this study.

Synthesis, structure and tunable shape memory properties of polytriazoles: dual-trigger temperature and repeatable shape recovery

2015 ◽  
Vol 3 (21) ◽  
pp. 11596-11606 ◽  
Author(s):  
M. Ragin Ramdas ◽  
K. S. Santhosh Kumar ◽  
C. P. Reghunadhan Nair
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Shape Memory Polymers ◽  
Shape Memory Properties

Click assisted synthesis resulted in low, high and dual trigger temperature shape memory polymers. They exhibit high shape recovery and repeatability in shape memory properties.

scholarly journals Review of Magnetic Shape Memory Polymers and Magnetic Soft Materials

2021 ◽  
Vol 7 (9) ◽  
pp. 123
Author(s):  
Sanne J. M. van Vilsteren ◽  
Hooman Yarmand ◽  
Sepideh Ghodrat
Keyword(s):  
Shape Memory ◽  
Magnetic Particles ◽  
Shape Memory Polymers ◽  
Soft Materials ◽  
Detailed Knowledge ◽  
Magnetic Shape Memory ◽  
Shape Transformation ◽  
Memory Recovery ◽  
Constitutive Response ◽  
Near Future

Magnetic soft materials (MSMs) and magnetic shape memory polymers (MSMPs) have been some of the most intensely investigated newly developed material types in the last decade, thanks to the great and versatile potential of their innovative characteristic behaviors such as remote and nearly heatless shape transformation in the case of MSMs. With regard to a number of properties such as shape recovery ratio, manufacturability, cost or programming potential, MSMs and MSMPs may exceed conventional shape memory materials such as shape memory alloys or shape memory polymers. Nevertheless, MSMs and MSMPs have not yet fully touched their scientific-industrial potential, basically due to the lack of detailed knowledge on various aspects of their constitutive response. Therefore, MSMs and MSMPs have been developed slowly but their importance will undoubtedly increase in the near future. This review emphasizes the development of MSMs and MSMPs with a specific focus on the role of the magnetic particles which affect the shape memory recovery and programming behavior of these materials. In addition, the synthesis and application of these materials are addressed.

scholarly journals Polydopamine coated shape memory polymer: enabling light triggered shape recovery, light controlled shape reprogramming and surface functionalization

2016 ◽  
Vol 7 (7) ◽  
pp. 4741-4747 ◽  
Author(s):  
Zhen Li ◽  
Xiaoyong Zhang ◽  
Shiqi Wang ◽  
Yang Yang ◽  
Benye Qin ◽  
...  
Keyword(s):  
Shape Memory ◽  
Surface Functionalization ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
Dip Coating ◽  
Responsive Materials ◽  
Thermally Responsive

Simple dip-coating transforms thermally responsive shape memory polymers into photo-responsive materials and allows for shape engineering and surface functionalization.

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