scholarly journals A new class of vitrimers based on aliphatic poly(thiourethane) networks with shape memory and permanent shape reconfiguration

2020 ◽  
Vol 122 ◽  
pp. 109361 ◽  
Author(s):  
Francesco Gamardella ◽  
Federico Guerrero ◽  
Silvia De la Flor ◽  
Xavier Ramis ◽  
Angels Serra
Keyword(s):  
Shape Memory ◽  
New Class ◽  
Permanent Shape

Mechanical Properties of Polymer Blends Having Shape-memory Capability

2009 ◽  
Vol 1190 ◽  
Author(s):  
Marc Behl ◽  
Ute Ridder ◽  
Wolfgang Wagermaier ◽  
Steffen Kelch ◽  
Andreas Lendlein
Keyword(s):  
Mechanical Properties ◽  
Polymer Blends ◽  
Shape Memory ◽  
Design Principle ◽  
Shape Memory Polymers ◽  
Multiblock Copolymers ◽  
New Class ◽  
Binary Polymer ◽  
Permanent Shape ◽  
Switching Temperature

AbstractThe general design principle of shape-memory polymers (SMP) requires two key compo-nents: covalent or physical crosslinks (hard domains) determining the permanent shape and switching domains fixing the temporary shape as well as influencing the switching temperature Tsw. In conventional thermoplastic SMP hard and switching domains determining segments are combined in one macromolecule, e.g. block copolymers such as polyurethanes. Recently, binary polymer blends having shape-memory properties, from two different multiblock copolymers have been presented, whereby the first one is providing the segments forming hard domains and the second one the segments forming the switching domains. Besides the shape-memory proper-ties, the mechanical properties of such materials are application relevant. Here we investigate how the blend composition influences mechanical properties of this new class of shape-memory materials.

B2 Intermetallic Compounds of Zr. New Class of the Shape Memory Alloys

1995 ◽  
Vol 05 (C8) ◽  
pp. C8-1103-C8-1108 ◽  
Author(s):  
Yu.N. Koval ◽  
G.S. Firstov ◽  
J.V. Humbeeck ◽  
L. Delaey ◽  
W.Y. Jang
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Intermetallic Compounds ◽  
New Class

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.

Using Multiscale Modeling to Predict Material Response of Polymeric Materials

2009 ◽  
Author(s):  
Richard V. Beblo ◽  
Lisa Mauck Weiland
Keyword(s):  
Shape Memory ◽  
Multiscale Modeling ◽  
Shape Memory Polymer ◽  
Polymeric Materials ◽  
Scale Model ◽  
Molecular Formula ◽  
Thermal Stimulus ◽  
Rotational Isomeric State ◽  
New Class ◽  
Constraint Theory

Presented is a multiscale modeling method applied to light activated shape memory polymers (LASMP). LASMP are a new class of shape memory polymer (SMP) being developed for applications where a thermal stimulus is undesired. Rotational Isomeric State (RIS) theory is used to build a molecular scale model of the polymer chain yielding a list of distances between the predicted cross-link locations, or r-values. The r-values are then fit with Johnson probability density functions and used with Boltzmann statistical mechanics to predict stress as a function of strain of the phantom network. Junction constraint theory is then used to calculate the stress contribution due to interactions with neighboring chains, resulting in previously unattainable numerically accurate Young’s modulus predictions based on the molecular formula of the polymer. The system is modular in nature and thus lends itself well to being adapted for specific applications. The results of the model are presented with experimental data for confirmation of correctness along with discussion of the potential of the model to be used to computationally adjust the chemical composition of LASMP to achieve specified material characteristics, greatly reducing the time and resources required for formula development.

scholarly journals Bioinspired fiber-regulated composite with tunable permanent shape and shape memory properties via 3d magnetic printing

2019 ◽  
Vol 164 ◽  
pp. 458-466 ◽  
Author(s):  
Luquan Ren ◽  
Bingqian Li ◽  
Zhengyi Song ◽  
Qingping Liu ◽  
Lei Ren ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Properties ◽  
Permanent Shape

Shape Memory Epoxy Foams: New Materials for Aerospace Applications

2012 ◽  
Vol 706-709 ◽  
pp. 165-172 ◽  
Author(s):  
Loredana Santo
Keyword(s):  
Shape Memory ◽  
Space Shuttle ◽  
Compression Tests ◽  
New Materials ◽  
Deployable Structures ◽  
Aerospace Application ◽  
New Class ◽  
Aerospace Applications ◽  
Foaming Process ◽  
Structural Parts

In this paper, shape memory epoxy foams, obtained by the new solid-state foaming process for thermosetting resin powder, are investigated. Foaming experiments in different configurations, compression tests, constrained stress recovery tests, and density measurements are discussed. The interesting results seem to be very promising for the aerospace application of shape memory epoxy foams as light actuators, structural parts with reduced size during shipping, and expandable/deployable structures. Finally, an attractive experiment is introduced. It is designed for the next Space Shuttle STS-134/ULF-6 in I-25/26, on April 2011, with the aim to study the behavior of this new class of materials in microgravity.

scholarly journals The Directions of Creation of Unique Technologies in Medicine on the Basis of New Generation of Biocompatible Materials and Implants With Shape Memory

2017 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
V.E. Gunther
Keyword(s):  
High Temperature ◽  
Powder Metallurgy ◽  
Shape Memory ◽  
Biocompatible Materials ◽  
Induction Melting ◽  
Temperature Synthesis ◽  
New Class ◽  
High Temperature Synthesis ◽  
Melting Technique ◽  
New Generation

The article describes the main directions of creation of unique technologies in medicine on the basis of new generation of biocompatible materials and implants with shape memory effect (SME). Physical and biological fundamentals and principles of creating a new class of biocompatible superelastic TiNi-based materials were drafted. Manufacturing technique of TiNi-based materials with using the induction melting technique, self-extending high-temperature synthesis and powder metallurgy with a certain complex of properties for various fields of medicine have been developed.

Polyurethane with an ionic liquid crosslinker: a new class of super shape memory-like polymers

2018 ◽  
Vol 9 (31) ◽  
pp. 4205-4217 ◽  
Author(s):  
Prasanta Kumar Behera ◽  
Prantik Mondal ◽  
Nikhil K. Singha
Keyword(s):  
Ionic Liquid ◽  
Phase Separation ◽  
Shape Memory ◽  
Shape Recovery ◽  
Ionic Interaction ◽  
Double Network ◽  
New Class ◽  
Ionic Crosslinking ◽  
Shape Fixity

Polyurethane (PU) with an ionic liquid crosslinker (with a unique double network having a combination of covalent as well as ionic crosslinking) showed excellent shape-recovery as well as excellent shape-fixity properties compared to linear PU and non-ionic crosslinked PU. The non-ionic crosslinker resulted in hard and soft phases intermixing, whereas the ionic interaction in ionic liquid crosslinked PU kept the phase separation intact.

Shrinkage and Warpage in the Permanent Shape of Sape-Memory Polyurethane Parts

2022 ◽  
Vol 58 (4) ◽  
pp. 102-113
Author(s):  
Sukran Katmer ◽  
Cetin Karatas
Keyword(s):  
Shape Memory ◽  
Injection Moulding ◽  
Flow Direction ◽  
Injection Pressure ◽  
Cooling Time ◽  
Mould Temperature ◽  
Melt Temperature ◽  
Packing Pressure ◽  
Permanent Shape ◽  
Packing Time

The shape memory effect, as the most important ability of shape memory polymers, is a working property and provides the design ability to shape memory polymer features. Shrinkage and warpage are important parameters to control the dimensional accuracy of permanent and temporary shapes of an injection moulded shape memory polyurethane (SMPU) part. In this study, the effects of injection moulding parameters on the shrinkage and warpage of the permanent shape of moulded SMPU parts were experimentally investigated. The parameters of injection pressure, melt temperature, mould temperature, packing pressure, packing time, and cooling time, were chosen as the injection moulding control factors. Taguchi�s L27 orthogonal array design table was used with six injection moulding parameters and their three levels. The results showed that the part has different shrinkage ratios in three main directions, namely, the flow direction, perpendicular to the flow direction, and the direction through the thickness. The results of the analysis of variance showed that the cooling time is the most influential parameter on both the shrinkage (except in thickness) and warpage. The shrinkage in the flow direction as well as in perpendicular to the flow direction decreased with increasing the cooling time. Warpage also decreased with increasing the cooling time. Injection pressure and melt temperature were found to be effective on shrinkage in thickness. Effects of mould temperature, packing pressure, and packing time were found to be limited. A statistically significant relationship has been noticed among shrinkage, warpage, and residual stresses during the study.

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