Remote, fast actuation of programmable multiple shape memory composites by magnetic fields

2015 ◽  
Vol 3 (43) ◽  
pp. 11290-11293 ◽  
Author(s):  
F. H. Zhang ◽  
Z. C. Zhang ◽  
C. J. Luo ◽  
I-Ting Lin ◽  
Yanju Liu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Body Temperature ◽  
Magnetic Fields ◽  
Surface Temperature ◽  
Shape Memory ◽  
Composite Membrane ◽  
Shape Recovery ◽  
Recovery Behavior ◽  
Shape Memory Composites

Magnetic field actuated shape recovery behavior of a 3D box folded by a Nafion/Fe3O4composite membrane with its surface temperature near body temperature.

Characristics of Shape Memory Composites Combined with Shape Memory Alloy and Shape Memory Polymer

2013 ◽  
Vol 705 ◽  
pp. 169-172
Author(s):  
Xue Feng ◽  
Li Min Zhao ◽  
Xu Jun Mi
Keyword(s):  
Shape Memory ◽  
Room Temperature ◽  
Shape Recovery ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Young Modulus ◽  
Thermomechanical Properties ◽  
The Matrix ◽  
Shape Memory Composites ◽  
Shape Fixity

In order to develop high functionality of shape memory materials, the shape memory composites combined with TiNi wire and shape memory epoxy were prepared, and the mechanical and thermomechanical properties were studied. The results showed the addition of TiNi wire increased the Young modulus and breaking strength both at room temperature and at elevated temperature. The composites maintained the rates of shape fixity and shape recovery close to 100%. The maximum recovery stress increased with increasing TiNi wire volume fraction, and obtained almost 3 times of the matrix by adding 1vol% TiNi wire.

scholarly journals Degradable Poly(ether-ester-urethane)s Based on Well-Defined Aliphatic Diurethane Diisocyanate with Excellent Shape Recovery Properties at Body Temperature for Biomedical Application

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1002 ◽  
Author(s):  
Minghui Xiao ◽  
Na Zhang ◽  
Jie Zhuang ◽  
Yuchen Sun ◽  
Fang Ren ◽  
...  
Keyword(s):  
Body Temperature ◽  
Shape Memory ◽  
Tensile Properties ◽  
Shape Recovery ◽  
Biomedical Application ◽  
Degradation Products ◽  
Chain Extension ◽  
Chemical Structures ◽  
Ether Ester

The aim of this study is to offer a new class of degradable shape-memory poly(ether-ester-urethane)s (SMPEEUs) based on poly(ether-ester) (PECL) and well-defined aliphatic diurethane diisocyanate (HBH) for further biomedical application. The prepolymers of PECLs were synthesized through bulk ring-opening polymerization using ε-caprolactone as the monomer and poly(ethylene glycol) as the initiator. By chain extension of PECL with HBH, SMPEEUs with varying PEG content were prepared. The chemical structures of the prepolymers and products were characterized by GPC, 1H NMR, and FT-IR, and the effect of PEG content on the physicochemical properties (especially the shape recovery properties) of SMPEEUs was studied. The microsphase-separated structures of the SMPEEUs were demonstrated by DSC and XRD. The SMPEEU films exhibited good tensile properties with the strain at a break of 483%–956% and an ultimate stress of 23.1–9.0 MPa. Hydrolytic degradation in vitro studies indicated that the time of the SMPEEU films becoming fragments was 4–12 weeks and the introduction of PEG facilitates the degradation rate of the films. The shape memory properties studies found that SMPEEU films with a PEG content of 23.4 wt % displayed excellent recovery properties with a recovery ratio of 99.8% and a recovery time of 3.9 s at body temperature. In addition, the relative growth rates of the SMPEEU films were greater than 75% after incubation for 72 h, indicating good cytocompatibility in vitro. The SMPEEUs, which possess not only satisfactory tensile properties, degradability, nontoxic degradation products, and cytocompatibility, but also excellent shape recovery properties at body temperature, promised to be an excellent candidate for medical device applications.

Method to Analyze Chemo-Mechanical Behavior of Shape Memory Polymer in Response to Solvent

2011 ◽  
Vol 230-232 ◽  
pp. 21-25
Author(s):  
Hai Bao Lu ◽  
Jin Ying Yin ◽  
Jiu Si Jia
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Chemical Potential ◽  
Shape Memory Polymer ◽  
Entropy Change ◽  
Dipole Interaction ◽  
Positive Definite ◽  
Free Energy Function ◽  
Mechanical Instability ◽  
Recovery Behavior

Thermo-responsive shape-memory polymer (SMP) has been experimentally demonstrated that shape recovery can be induced by plasticizing solvent. Subject to being immersed into solvent, deformed SMP recover from the temporary shape to original shape, leading to shape recovery induced by the molecular interaction. The actuation of styrene-based SMP has been carried out by electrostatic dipole-dipole interaction and physical swelling effect, respectively. The model can be used to predict the effect of prestress, strain, volume change and chemical potential on SMP actuation in the solvent. Finally, it is found that the simulation agrees well with experimental results. The authors show that the chemo-mechanical instability occurs when the Hessian of the free-energy function ceases to the positive definite. Their calculations show that the shape recovery behavior of SMP is driven by the entropy change markedly, agreeing with existing experimental observations.

scholarly journals Effect of Ni, C and Ti Addition on Shape Recovery Behavior and the Mechanical Properties of Fe-17Mn-5Si-5Cr Shape Memory Alloys

2020 ◽  
Vol 58 (10) ◽  
pp. 660-671 ◽  
Author(s):  
Dohyoung Kim ◽  
Yonghwan Kim ◽  
Jeong-Jung Oak ◽  
Junghoon Lee ◽  
Chan Hee Park ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Shape Memory ◽  
Shape Recovery ◽  
Base Alloy ◽  
Recovery Ratio ◽  
Engineering Structures ◽  
Recovery Behavior ◽  
Heat Treated Condition ◽  
Co Addition ◽  
Functional Components

Fe-Mn-Si based shape memory alloy is a new functional material that can be used to apply prestress to civil and structural components such as concrete structures. In this study, the effects of alloying elements Ni, C and Ti on the mechanical and shape memory properties of the alloy were investigated in detail using a base alloy composition of Fe-17Mn-5Si-5Cr (wt%). Enhanced shape recovery ratio and decreasing strength were observed in the alloy when 4 wt% Ni was added. With the further addition of 0.05 wt% C, the alloy showed even higher shape recovery behavior, although the mechanical strength was lowered by the C addition. Increasing the carbon content up to 0.1 wt% led to higher mechanical strength while the shape recovery ratio was decreased slightly. It was shown that the addition of 1 wt% Ti can significantly enhance the shape recovery behavior of the alloy. The recovery behavior of the alloy with the co-addition of 0.3 wt% C and 1 wt% Ti was similar to the alloy without Ti but containing 0.1 wt% C, even though the C content was significantly higher. The alloy with the co-addition of 0.3 wt% C and 1 wt% Ti has great potential as functional components in prestressed civil engineering structures, since the yield strength of the alloy is as high as 400 MPa in the solution heat treated condition and can be further improved by aging heat treatments, which precipitate TiC particles.

Shape recovery characteristics of shape memory cyanate ester/epoxy composite reinforced with calcium sulfate whisker

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yongkun Wang ◽  
Yuting Zhang ◽  
Jinhua Zhang ◽  
Junjue Ye ◽  
Wenchao Tian
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Calcium Sulfate ◽  
High Performance ◽  
Shape Recovery ◽  
Bending Strength ◽  
Cyanate Ester ◽  
Content Type ◽  
Shape Memory Composites ◽  
Calcium Sulfate Whiskers

Purpose The purpose of this paper is to study the influence of calcium sulfate whiskers (CSWs) on the thermodynamic properties and shape memory properties of epoxy/cyanate ester shape memory composites. Design/methodology/approach To improve the mechanical properties of shape memory cyanate ester (CE)/epoxy polymer (EP) resin, high performance CSWs were used to reinforce the thermo-induced shape memory CE/EP composites and the shape memory CSW/CE/EP composites were prepared by molding. The effect of CSW on the mechanical properties and shape memory behavior of shape memory CE/EP composites was investigated. Findings After CSW filled the shape memory CE/EP composites, the bending strength of the composites is greatly improved. When the content of CSW is 5 Wt.%, the bending strength of the composite is 107 MPa and the bending strength is increased by 29 per cent compared with bulk CE/EP resin. The glass transition temperature and storage modulus of the composites were improved in CE/EP resin curing system. However, when the content of CSW is more than 10 Wt.%, clusters are easily formed between whiskers and the voids between whiskers and matrix increase, which will lead to the decrease of mechanical properties of composites. The results of shape memory test show that the shape memory recovery time of the composites decreases with the decrease of CSW content at the same temperature. In addition, the shape recovery ratio of the composites decreased slightly with the increase of the number of thermo-induced shape memory cycles. Research limitations/implications A simple way for fabricating thermo-activated SMP composites has been developed by using CSW. Originality/value The outcome of this study will help to fabricate the SMP composites with high mechanical properties and the shape memory CSW/CE/EP composites are expected to be used in space deployable structures.

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.

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