Stress-Induced Melting of Crystals in Natural Rubber: a New Way to Tailor the Transition Temperature of Shape Memory Polymers

2012 ◽  
Vol 33 (18) ◽  
pp. 1517-1522 ◽  
Author(s):  
Benjamin Heuwers ◽  
Dominik Quitmann ◽  
Frank Katzenberg ◽  
Joerg C. Tiller
Keyword(s):  
Transition Temperature ◽  
Natural Rubber ◽  
Shape Memory ◽  
Shape Memory Polymers

Flexural Testing of Shape Memory Polymers for Morphing Aircraft Applications

2007 ◽  
Author(s):  
Korey Gross ◽  
Lisa Weiland
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Shape Memory ◽  
Shape Memory Polymers ◽  
Morphing Aircraft ◽  
Flexural Testing ◽  
Soft State ◽  
Out Of Plane ◽  
Hard State ◽  
Significant Attention

Shape memory polymers (SMPs) have garnered significant attention in recent years for their potential to return to a “memorized” state when warmed above their glass transition temperature Tg. However, they also have potential in morphing aircraft applications because of their significant modulus change above and below Tg. Much less energy is required to deform this material when in its soft state, but when the material returns to the hard state, it is able to support significant loads. In the proposed effort, SMP is experimentally considered as a candidate material for morphing aircraft applications where the material’s ability to support out of plane loads above and below the Tg is of primary importance. The SMP of study in the work is Veriflex®.

scholarly journals Multi-Material 3D Printed Shape Memory Polymer with Tunable Melting and Glass Transition Temperature Activated by Heat or Light

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 710 ◽  
Author(s):  
Ela Sachyani Keneth ◽  
Rama Lieberman ◽  
Matthew Rednor ◽  
Giulia Scalet ◽  
Ferdinando Auricchio ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Shape Memory ◽  
Smart Materials ◽  
Shape Memory Polymer ◽  
3D Structure ◽  
Three Dimensional ◽  
Shape Memory Polymers ◽  
Practical Applications ◽  
Different Temperatures ◽  
Robotic Devices

Shape memory polymers are attractive smart materials that have many practical applications and academic interest. Three-dimensional (3D) printable shape memory polymers are of great importance for the fabrication of soft robotic devices due to their ability to build complex 3D structures with desired shapes. We present a 3D printable shape memory polymer, with controlled melting and transition temperature, composed of methacrylated polycaprolactone monomers and N-Vinylcaprolactam reactive diluent. Tuning the ratio between the monomers and the diluents resulted in changes in melting and transition temperatures by 20, and 6 °C, respectively. The effect of the diluent addition on the shape memory behavior and mechanical properties was studied, showing above 85% recovery ratio, and above 90% fixity, when the concentration of the diluent was up to 40 wt %. Finally, we demonstrated multi-material printing of a 3D structure that can be activated locally, at two different temperatures, by two different stimuli; direct heating and light irradiation. The remote light activation was enabled by utilizing a coating of Carbon Nano Tubes (CNTs) as an absorbing material, onto sections of the printed objects.

New Design of Shape Memory Polymers Based on Natural Rubber Crosslinked via Oxa-Michael Reaction

2014 ◽  
Vol 6 (8) ◽  
pp. 5695-5703 ◽  
Author(s):  
Tengfei Lin ◽  
Siwei Ma ◽  
Yang Lu ◽  
Baochun Guo
Keyword(s):  
Natural Rubber ◽  
Shape Memory ◽  
Michael Reaction ◽  
Shape Memory Polymers

Development of Thermally-Activated Shape Memory Polymers and Nanocomposites for Biomedical Devices

2017 ◽  
Author(s):  
Jingyu Wang ◽  
Shoieb Chowdhury ◽  
Yingtao Liu ◽  
Bradley Bohnstedt ◽  
Chung-Hao Lee
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Shape Memory ◽  
Thermal Activation ◽  
Memory Function ◽  
Shape Memory Polymers ◽  
Thermally Activated

Shape memory polymers (SMPs) have been developed as an emerging technology platform for biomedical applications in the past decades. In particular, SMPs are clinically essential for the development of novel medical devices to significantly improve long-term surgical outcomes. In this paper, we synthesized and characterized thermally-activated aliphatic urethane SMPs fabricated with nanocomposites for the design and development of biomedical devices. The thermal activation of shape memory function was investigated by direct thermal activation. Critical polymer properties, such as the glass transition temperature and shape memory function, have been tailored to desired applications, by adjusting the polymer composition. Carbon nanotubes were uniformly dispersed within the polymer during nanocomposite fabrication to significantly enhance the thermal and electrical properties. The synthesized SMPs and nanocomposites were characterized to understand their thermal and mechanical properties using dynamic mechanical analysis (DMA). Scanning electron microscopy was employed to evaluate the dispersion of carbon nanotubes in polymer matrix. The mechanical properties of SMPs and nanocomposites at temperature above their glass transition temperature were evaluated using dog-bone samples in a dual-column mechanical testing system and an environmental chamber. SMPs and nanocomposites will then be fabricated in the form of foam for the development of novel devices applicable to endovascular embolization of cerebral aneurysms.

Optically transparent high temperature shape memory polymers

Soft Matter ◽  
2016 ◽  
Vol 12 (11) ◽  
pp. 2894-2900 ◽  
Author(s):  
Xinli Xiao ◽  
Xueying Qiu ◽  
Deyan Kong ◽  
Wenbo Zhang ◽  
Yanju Liu ◽  
...  
Keyword(s):  
Glass Transition ◽  
High Temperature ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Shape Memory ◽  
Shape Memory Polymers ◽  
Optically Transparent

Optically transparent shape memory polyimide exhibiting a glass transition temperature higher than those of other transparent shape memory polymers is reported.

scholarly journals The Shape-Memory Effect of Hindered Phenol (AO-80)/Acrylic Rubber (ACM) Composites with Tunable Transition Temperature

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2461 ◽  
Author(s):  
Shi-kai Hu ◽  
Si Chen ◽  
Xiu-ying Zhao ◽  
Ming-ming Guo ◽  
Li-qun Zhang
Keyword(s):  
Transition Temperature ◽  
Shape Memory ◽  
Molecular Hydrogen ◽  
Shape Recovery ◽  
Organic Molecules ◽  
Shape Memory Polymers ◽  
Carbonyl Groups ◽  
Rubber Composites ◽  
Small Organic Molecules ◽  
Hindered Phenol

To broaden the types and scope of use of shape-memory polymers (SMPs), we added the hindered phenol 3,9-bis[1,1-dimethyl-2-{b-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro-[5,5]-undecane (AO-80), which comprises small organic molecules, to acrylic rubber (ACM) to form a series of AO-80/ACM rubber composites. The structural, thermal, mechanical property, and shape-memory properties of the AO-80/ACM rubber composites were investigated. We identified the formation of intra-molecular hydrogen bonding between –OH of AO-80 and the carbonyl groups and the ether groups of ACM molecules. The amount of AO-80 used can be adjusted to tailor the transition temperature. AO-80/ACM rubber composites showed excellent shape recovery and fixity. The approach for adjusting the transition temperature of AO-80/ACM rubber composites provides remarkable ideas for the design and preparation of new SMPs.

scholarly journals Electrical Properties of Thiol-ene-based Shape Memory Polymers Intended for Flexible Electronics

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 902 ◽  
Author(s):  
Christopher L. Frewin ◽  
Melanie Ecker ◽  
Alexandra Joshi-Imre ◽  
Jonathan Kamgue ◽  
Jeanneane Waddell ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Electrical Properties ◽  
Shape Memory ◽  
Flexible Electronics ◽  
Shape Memory Polymers ◽  
Curing Process ◽  
Uv Curable ◽  
Processing Technologies

Thiol-ene/acrylate-based shape memory polymers (SMPs) with tunable mechanical and thermomechanical properties are promising substrate materials for flexible electronics applications. These UV-curable polymer compositions can easily be polymerized onto pre-fabricated electronic components and can be molded into desired geometries to provide a shape-changing behavior or a tunable softness. Alternatively, SMPs may be prepared as a flat substrate, and electronic circuitry may be built directly on top by thin film processing technologies. Whichever way the final structure is produced, the operation of electronic circuits will be influenced by the electrical and mechanical properties of the underlying (and sometimes also encapsulating) SMP substrate. Here, we present electronic properties, such as permittivity and resistivity of a typical SMP composition that has a low glass transition temperature (between 40 and 60 °C dependent on the curing process) in different thermomechanical states of polymer. We fabricated parallel plate capacitors from a previously reported SMP composition (fully softening (FS)-SMP) using two different curing processes, and then we determined the electrical properties of relative permittivity and resistivity below and above the glass transition temperature. Our data shows that the curing process influenced the electrical permittivity, but not the electrical resistivity. Corona-Kelvin metrology evaluated the quality of the surface of FS-SMP spun on the wafer. Overall, FS-SMP demonstrates resistivity appropriate for use as an insulating material.

Design, Development and Evaluation of a Two Way Actuated Steerable Needle

2015 ◽  
Author(s):  
Bardia Konh ◽  
Harold H. Lee ◽  
Vincent P. Martin ◽  
Vincent Zhao ◽  
Daehoon Han ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Glass Transition ◽  
Transition Temperature ◽  
Shape Memory ◽  
Shape Memory Polymers ◽  
Design Development ◽  
Actuation Force ◽  
Needle Deflection ◽  
And Control ◽  
Steerable Needle

Over the last two decades, researchers have been interested to provide actuation and control for surgical needles. It has been recently suggested to utilize shape memory alloy (SMA) wires to provide bending forces to activate the conventional straight needles. In this paper a design of an active needling system has been proposed where actuation forces of SMAs as well as shape memory polymers (SMPs) were incorporated. SMP elements provide two major additional advantages to the design: (i) recovery of the SMP’s plastic deformation by heating the element above its glass transition temperature, and (ii) achieving a higher needle deflection by having a softer stage of SMP at higher temperatures with less amount of actuation force. The feasibility of providing actuation forces using both SMAs and SMPs for the surgical needle was demonstrated in this study.

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