Shape memory polymers (SMPs) represent a highly interesting class of materials. As one representative of the intelligent polymeric systems, these materials gained significant interest in recent ...years. Consequently, the variety of materials investigated virtually exploded and several promising shape memory effects have been developed. The present review will provide a short overview on the history of SMPs as well as the current developments and concepts for shape memory polymers. Additionally, future developments in this field will be discussed.
Shaping tissue with shape memory materials Huang, W.M.; Song, C.L.; Fu, Y.Q. ...
Advanced drug delivery reviews,
April 2013, 2013-Apr, 2013-04-00, 20130401, Letnik:
65, Številka:
4
Journal Article
Recenzirano
After being severely and quasi-plastically deformed, shape memory materials are able to return to their original shape at the presence of the right stimulus. After a brief presentation about the ...fundamentals, including various shape memory effects, working mechanisms, and typical shape memory materials for biomedical applications, we summarize some major applications in shaping tissue with shape memory materials. The focus is on some most recent development. Outlook is also discussed at the end of this paper.
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Shape‐memory polymers (SMPs) are well investigated smart materials. With their ability to memorize their original shape they are interesting candidates for a large range of applications. Certain SMPs ...feature triple shape‐memory behavior. In these cases, it is possible to fix two different temporary shapes. However, the exact quantification of the individual steps regarding their programming and recovery rate is difficult and has not been possible so far. In this work, a novel approach for the analysis and exact quantification of triple SMPs is presented. By applying a customized rheology protocol, it is possible to perform and to analyze torsional and tensional experiments simultaneously. Consequently, different shapes in different directions (vertical and horizontal) can be fixed and the individual steps can be investigated independently at different switching temperatures.
A new method for the quantification of triple‐shape memory behavior of polymers is presented. For this purpose, twisting and elongation are studied separately from each other enabling the investigation of each recovery step without the interference of the other one. Thus, realistic values for the triple‐shape memory behavior are obtained.
Two new thermoresponsive self‐healing polyurethanes (1DA1T and 1.5DA1T) based on the Diels–Alder (DA) reaction between furan and maleimide moieties are developed that use the shape‐memory effect to ...bring crack faces into intimate contact such that healing can take place. Unlike other self‐healing polymers, these polymers do not require external forces to close cracks but rather they use the shape‐memory effect to autonomously close the crack. Both polyurethanes have a stable polymer structure and comparable mechanical properties to commercial epoxies. A differential scanning calorimeter is employed to check the glass transition temperature of the polymers as well as the DA and retro‐DA (rDA) reaction temperatures. These DA and rDA reactions are confirmed with variable‐temperature proton nuclear magnetic resonance. Healing efficiency is calculated using a measurement of the failure load from compact tension testing. The results show that the shape‐memory effect can replace external forces to close two crack surfaces and the DA reaction can be repeatedly employed to heal the cracks.
Thermo‐responsive self‐healing polyurethanes that can be healed repeatedly without the application of external forces are developed. Instead, these polymers use the shape‐memory effect to autonomously bring the two crack surfaces together during the healing process.
Shape memory polymers (SMPs) are capable of changing their shapes in a pre-defined manner under a stimulus, and have gained considerable interest in the past decades. Although a number of ...stimulus-responsive SMPs have been developed, thermally-induced SMPs are still the most common. This review presents the concepts, the programming procedures, the molecular mechanism, classification, design strategies and the recent progress of thermally-induced SMPs, including dual, triple, multiple SMPs and two-way reversible SMPs (2W-SMPs) activated by direct and indirect heating method. Examples of the applications of these types of SMPs are also presented and discussed.
•An 4D printed SMC actuator was fabricated using SMA and SMP with a FDM 3D printer.•A volume fraction of SMA:SMP of 1:5 showed the largest length change of 8 mm, and the most rapid response time of 4 ...s.•The reversible actuator mechanism explains the SMC actuation via each shape memory effect.•SMC showed potential application for stents and valve controllers via 3D printing technology to achieve customized designs.
A fused deposition modeling (FDM) tool was used to fabricate a shape memory composite (SMC) that combined a shape memory alloy (SMA) with a shape memory polymer (SMP). The SMA caused a shape memory effect due to a phase change between martensite and austenite phases, in turn due to a temperature change. Also, the SMP had a shape memory effect caused by changes in the proportions of hard and soft segments near the glass transition temperature (Tg). Usually, common SMAs and SMPs are not reversible, so these materials do not go back to their original shapes once they are deformed. In this study, we fabricated 4D printing actuator via reversible SMC actuations using 3D printing technology. Nylon 12 was used as the 3D printing material in filament form. Moreover, the volume fraction of SMA to SMP was varied to find the optimum ratio for good operation cycles. A volume fraction of SMA:SMP of 1:5 showed the largest length change, of 8 mm, and the most rapid response time, of 4 s in overall dimension of 140mm×10mm×1mm (length×width×thickness).Thus, the SMC showed promising results for the application of stents and valve controllers that could be manufactured by 3D printing technology.
This overview of the most recent advances in the field of SMA research and applications in civil engineering aims to help remove the knowledge barriers across disciplines and sheds considerable light ...on the opportunity to commercialize SMA products in the construction industry.
Shape memory polymers (SMPs) are smart and adaptive materials able to recover their shape through an external stimulus. This functionality, combined with the good biocompatibility of polymers, has ...garnered much interest for biomedical applications. In this review, we discuss the design considerations critical to the successful integration of SMPs for use in vivo. We also highlight recent work on three classes of SMPs: shape memory polymers and blends, shape memory polymer composites, and shape memory hydrogels. These developments open the possibility of incorporating SMPs into device design, which can lead to vast technological improvements in the biomedical field.
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