scholarly journals Multi-shape memory effect of polyimides with extremely high strain

RSC Advances ◽  
2017 ◽  
Vol 7 (84) ◽  
pp. 53492-53496 ◽  
Author(s):  
Jianan Yao ◽  
Zhao Zhang ◽  
Chunbo Wang ◽  
Shengqi Ma ◽  
Tianqi Li ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
High Strain ◽  
Synergistic Effects ◽  
Shape Memory Properties ◽  
Chemical Crosslinks ◽  
Physical And Chemical

Polyimides exhibited high strain and multi-shape memory properties with the synergistic effects of physical and chemical crosslinks.

Nitinol Alloys - Study of Physical and Chemical Application as Biomaterials

2014 ◽  
Vol 805 ◽  
pp. 3-6
Author(s):  
Isabel Portela Rabello ◽  
Carmem Dolores de Sá Catão ◽  
Germana Portela Rabello ◽  
Marcus Vinícius Lia Fook
Keyword(s):  
Heat Treatment ◽  
Surface Tension ◽  
Shape Memory ◽  
Titanium Alloys ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Medical Devices ◽  
Chemical Application ◽  
The Family ◽  
Physical And Chemical

The Nitinol is a term which represents the family of nickel and titanium alloys. With the discovery of the extraordinary biocompatibility of these alloys, their implementation has been emphasized in the medical devices and in general dentistry. The characteristics which make these alloys are of interest its superelasticity, shape memory effect and excellent biocompatibility, the latter two characteristics particularly interesting due to the fact that these materials confer the ability to self-expansion or contraction and not presenting rejection the organism. Thus, this study aims to evaluate three NiTi alloys compositions, being one rich in titanium, other poor and the last equiatomic, through tests of physical characterization and surface tension, after different heat treatments. After the results interpretation, it can be seen that the lower percentages by weight of nickel in their products from corrosion was the Nitinol rich in titanium subjected to heat treatment for 24 hours in the oven. Moreover, the same composition present the smallest angle in the test of surface tension.

Poly(carbonate-urea-urethane) networks exhibiting high-strain shape-memory effect

2016 ◽  
Vol 28 (10) ◽  
pp. 1285-1293 ◽  
Author(s):  
Magdalena Mazurek-Budzyńska ◽  
Muhammad Yasar Razzaq ◽  
Karolina Tomczyk ◽  
Gabriel Rokicki ◽  
Marc Behl ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
High Strain ◽  
Poly Carbonate

Effect of Grain Refinement on Shape Memory Properties of Cu-Al-Mn SMAs

2015 ◽  
Vol 1101 ◽  
pp. 104-107 ◽  
Author(s):  
U.S. Mallik ◽  
Vedamanickam Sampath
Keyword(s):  
Grain Size ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Compositional Analysis ◽  
Tensile Tests ◽  
Ingot Metallurgy ◽  
Grain Refiner ◽  
Shape Memory Properties ◽  
Microstructural Examination

Cu-12.5 wt.% Al-5 wt.% Mn-(0.05 to 0.2) wt.% B alloys were prepared by ingot metallurgy. The Aluminum and Manganese contents of the alloys were maintained constant, while that of Boron was varied. The alloys were then characterized by subjecting them to compositional analysis, Differential Scanning Caloriemeter and microstructural examination. The shape memory effect and superelasticity of the alloys were determined by bend and tensile tests on the alloy specimens. The investigation reveals that Boron acts as a good grain refiner, resulting in a reduction of about 80% in grain size. The addition of Boron also increases the transformation temperatures by ~ 10oC, while at the same time decreasing the strain recovery by shape memory effect by 4%, and that by superelasticity by ~ 2%.

scholarly journals Shape-memory Nanofiber Meshes with Programmable Cell Orientation

2018 ◽  
Author(s):  
Eri Niiyam ◽  
Kanta Tanabe ◽  
Koichiro Uto ◽  
Akihiko Kikuchi ◽  
Mitsuhiro Ebara
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Rational Design ◽  
Hexamethylene Diisocyanate ◽  
Molar Ratio ◽  
Original Structure ◽  
Cell Functions ◽  
Shape Memory Properties ◽  
Hard Segments

This paper reports a rational design of temperature-responsive nanofiber meshes with shape-memory effect. The meshes were fabricated by electrospinning a poly(ε-caprolactone) (PCL)-based polyurethane with different contents of soft and hard segments. The effects of PCL diol/hexamethylene diisocyanate (HDI)/1,4-butanediol (BD) molar ratio in terms of the contents of soft and hard segments on the shape-memory properties were investigated. Although the mechanical property improved with increasing hard segment ratio, optimal shape-memory properties were obtained with a PCL/HDI/BD molar ratio of 1:4:3. At a microscopic level, the original nanofibrous structure was easily deformed into a temporary shape, and recovered its original structure when the sample was reheated. A higher recovery rate (>89%) was achieved even when the mesh was deformed up to 400%. Finally, the nanofiber meshes were used to control the alignment of human mesenchymal stem cells (hMSCs). The hMSCs aligned well along the fiber orientation. The proposed nanofibrous meshes with the shape-memory effect have the potential to serve as in vitro platforms for the investigation of cell functions as well as implantable scaffolds for wound-healing applications.

Tensile Failure of 55-Nitinol Wire

1975 ◽  
Vol 33 ◽  
pp. 46-47
Author(s):  
F. I. Grace
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Stoichiometric Composition ◽  
Tensile Failure ◽  
Initial State ◽  
Initial Shape ◽  
Nitinol Wire ◽  
Cscl Type ◽  
Shear Transformation

An interest in NiTi alloys with near stoichiometric composition (55 NiTi) has intensified since they were found to exhibit a unique mechanical shape memory effect at the Naval Ordnance Laboratory some twelve years ago (thus refered to as NITINOL alloys). Since then, the microstructural mechanisms associated with the shape memory effect have been investigated and several interesting engineering applications have appeared.The shape memory effect implies that the alloy deformed from an initial shape will spontaneously return to that initial state upon heating. This behavior is reported to be related to a diffusionless shear transformation which takes place between similar but slightly different CsCl type structures.

A new type of intrinsic two-way shape-memory effect in hooks of NiTi-wires

2003 ◽  
Vol 112 ◽  
pp. 1177-1180 ◽  
Author(s):  
A. Schuster ◽  
H. F. Voggenreiter ◽  
D. C. Dunand ◽  
G. Eggeler
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
New Type ◽  
Niti Wires

Experimental study of the out-of-equilibrium behavior of the two-way shape memory effect

2003 ◽  
Vol 112 ◽  
pp. 765-768 ◽  
Author(s):  
Y. Bellouard ◽  
R. Clavel ◽  
R. Gotthardt ◽  
J. van Humbeeck
Keyword(s):  
Experimental Study ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Equilibrium Behavior
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