Triple shape memory polymers by 4D printing

Bodaghi, Mahdi; Damanpack, A.R.; Liao, Wei-Hsin

doi:10.1088/1361-665x/aabc2a

Cited by 142 publications

(111 citation statements)

References 24 publications

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“…This was because of the presence of oligomeric species. Such species might not react completely with the isocyanate and may leave the material with a lower physical crosslinking density, as already noted …”

Section: Resultsmentioning

confidence: 71%

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Highly functional lactic acid ring‐opened soybean polyols applied to rigid polyurethane foams

Herrán

Amalvy

Chiacchiarelli

2019

J of Applied Polymer Sci

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We synthesized polyols with high hydroxyl functionalities (F OH s), between 9.0 and 12.6, and characterized them with differential scanning calorimetry, thermogravimetric analysis, and size exclusion chromatography after we parametrically studied the ringopening reaction of epoxidized soybean oil with lactic acid (LA) as a function of the reaction temperature and lactic acid equivalent fraction (f LA ). An increase of only 20 C in the reaction temperature (from 80 to 100 C) caused changes in the hydroxyl number (+17.8%), F OH (-25%), viscosity (-14.0%), and oligomeric content (-24.1%). f LA mostly affected the ring-opening yield, and only for f LA values above 0.4 was possible to achieve values higher than 80%. Rigid polyurethane foams (rPUFs) were synthesized and characterized with scanning electron microscopy, dynamic mechanical analysis (DMA), and compressive mechanical tests. rPUFs with a very high specific compressive strength (7.8 kPa kg -1 m 3 ) were synthesized solely with biobased soybean oil. DMA revealed a compromised relationship between the specific compressive strength and its temperature dependence. To increase the first one, the most relevant method was to increase F OH . Instead, to increase the latter one, the OH number had to be maximized.

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Section: Resultsmentioning

confidence: 71%

“…Future work will also consider the simulation of the effects of F OH , oligomeric content, and OH# on the thermomechanical properties of rPUF with the constitutive models presented by Bodaghi et al …”

Section: Resultsmentioning

confidence: 99%

Highly functional lactic acid ring‐opened soybean polyols applied to rigid polyurethane foams

Herrán

Amalvy

Chiacchiarelli

2019

J of Applied Polymer Sci

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“…In particular, multishape memory polymers (MSMPs) are materials that can “memorize” two or more temporary shapes. Triple‐,376–378 quadruple‐,379 and quintuple‐380 SMPs have each been described. Multishape programming of SME in polymers is enabled by the preparation of materials with multiple transitions.…”

Section: Shape Memory Polymersmentioning

confidence: 99%

“…The SMP's SME induces a change in the proportion of hard and soft segments, resulting in the shape change cycles. Bodaghi and co‐workers demonstrated how FDM can be used to functionally program the self‐folding of extruded filaments due to changes in fabrication parameters like printing‐speed and liquefier‐temperature 376,431,432. 3D printing techniques have been used to prepare SMP actuator units, and ultimately SMP meta‐material lattices, for self‐expanding and shape‐changing structures, along with actuating geometries such as hinges and coils.…”

Section: Shape Memory Polymersmentioning

confidence: 99%

Materials as Machines

2020

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of responsive materials as machines is in robotics. The vision, leadership, and research of Bar-Cohen is seminal in both invigorating and focusing current-day research activities to develop responsive materials [2] and implement [3] them as lightweight, dexterous, and gentle (e.g., soft) robotic elements. In this spirit, this review exhaustively details the materials, the nature of their stimuli-response, and discusses considerations for their implementation in robotic systems and subsystems.Robotics is a well-established but growing field of research. Sustained progress in both performance and functionality continue to be realized in commercial robotic systems largely based on conventional materials and their integration with mechanisms. A recent example is the Atlas robot from Boston Dynamics [4] (Figure 1a). The incorporation of stimuli-responsive materials in robotics has largely focused on component-level demonstrations to extend the performance of a subsystem (such as a hand or gripper).Stimuli-responsive materials, spanning nearly all classes of materials and size scales, are currently subject to widespread examination in corporate, government, and academic research laboratories (Figure 1b-d). [5][6][7] In some cases, these materials have already found widespread commercial implementation in end use and are comparatively mature. The materials and fundamentals of their responses are summarized in Figure 2. Shape memory alloys (SMAs) and ceramic piezoelectric materials are distinctive in that they are hard, stimuli-responsive materials. Deformation of these materials can produce large energy densities due to their inherent stiffness. Electroactive polymers (EAPs) remain a topic of considerable interest, particularly dielectric elastomer actuators (DEAs). Engineered systems are rapidly emerging and enabling performance gains in robotics, largely based on pneumatic or fluidic (such as HASEL [8] actuators) transport processes that localize deformation to generate force or produce motion. Soft materials, such as shape memory polymers (SMPs), hydrogels, and liquid crystalline polymer networks (LCNs) and elastomers (LCEs) may offer distinctive functional performance to robotic systems in allowing local control of deformation without the need for complex interfacing with mechanisms. As will be evident, each of these materials has inherent advantages and performance tradeoffs that must be considered in functional implementations. However, responsive material systems have a common obstacle to widespread use: the performance and Machines are systems that harness input power to extend or advance function. Fundamentally, machines are based on the integration of materials with mechanisms to accomplish tasks-such as generating motion or lifting an object. An emerging research paradigm is the design, synthesis, and integration of responsive materials within or as machines. Herein, a particular focus is the integration of responsive materials to enable robotic (machine) functions such as gripping, lifting, or motility (walk...

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“…Yu, Qi, and Liao et al presented the 1D rods that were bent into arcs with different curvatures (Fig. 13b) [114][115][116]. Huang printed a shape-memory polyurethane sheet and placed it in water at 85 • C to achieve folding deformation (Fig.…”

Section: Deformation Typesmentioning

confidence: 99%

Mechanical Models, Structures, and Applications of Shape-Memory Polymers and Their Composites

Xin

Liu

et al. 2019

Acta Mech. Solida Sin.

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Shape-memory polymers (SMPs) and their composite materials are stimuliresponsive materials that have the unique characteristics of lightweight, large deformation, variable stiffness, and biocompatibility. This paper reviews the research status of the mechanical models for SMPs, shape-memory nanocomposites and shape-memory polymer composites (SMPCs); it also introduces some spatially deployable structures, such as hinges, beams, and antennae based on SMPCs. In addition, the deformation types of 4D printing structures and the potential applications of this technology in robots and medical devices are also summarized.The mechanism of shape-memory cycles and the mechanical behavior of SMPs can be described by establishing thermomechanical models, which lay the theoretical foundations for the rational design of SMP structures. This section will focus on the constitutive models for SMPs, the micromechanical models of SMPNs, and the buckling behavior of SMPCs.

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Triple shape memory polymers by 4D printing

Cited by 142 publications

References 24 publications

Highly functional lactic acid ring‐opened soybean polyols applied to rigid polyurethane foams

Highly functional lactic acid ring‐opened soybean polyols applied to rigid polyurethane foams

Materials as Machines

Mechanical Models, Structures, and Applications of Shape-Memory Polymers and Their Composites

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