Material Selection

Safranski, David L.; Laffoon, Stephen L.; Sycks, Dalton G.; Gall, Ken

doi:10.1016/b978-0-323-37797-3.00003-8

Cited by 3 publications

(2 citation statements)

References 119 publications

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“…Various grades of commercial materials have been developed according to their use. PDMC18SP is comparable to Mitsubishi’s Diary and DiAPLEX series (polyurethanes, R f : 95 ∼ 99, R r : 84 ∼ 100) and CRG’s Veriflex series (styrene- and epoxy-based resins, R f : 72 ∼ 100, R r : 65 ∼ 98) in terms of shape memory performance . As expected, PTMSP exhibited no shape memory capability because it exists in glassy state over the studied temperature range and thus cannot show rubber elasticity at the source.…”

Section: Resultsmentioning

confidence: 99%

Molecular-Spring Shape-Memory Polymer Based on Energy Elasticity and Local Phase Transition

2019

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A molecular-spring polyacetylene, with a highly twisted helical main chain and a paraffin-like octadecyl side chain (PDMC18SP), was synthesized and compared with other polymer derivatives in terms of physicochemical, thermodynamic, and (thermo)mechanical properties. PDMC18SP had lower fractional free volume (0.15) and higher solubility parameter (18.4 MPa1/2) than other polymers. The chain packing structure was considerably collapsed at room temperature, resulting in a highly disordered amorphous phase. PDMC18SP was very soft at room temperature and could be stretched and contracted to large extents with very low tensile strength (0.7 MPa) and large strain (504.4%). PDMC18SP showed a distinct endothermic peak (30.0 J·g–1) due to the melting of the octadecyl side chains at ∼7.05 °C. This polymer showed a relatively high plateau modulus of ∼1.87 MPa and a low entanglement molecular weight of ∼1,410 g·mol–1. The mechanical deformation was fixed by cooling, and the original shape was readily recovered by heating.

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Section: Resultsmentioning

confidence: 99%

Molecular-Spring Shape-Memory Polymer Based on Energy Elasticity and Local Phase Transition

2019

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“…Maximum SMP recovery stresses, defined as the change in macroscopic stress produced by internal stress changes, generally cannot surpass 10 MPa while SMA recovery stresses commonly reach 500-900 MPa. [28,29] This recovery stress comparison suggests that SMAbased approaches may be better suited for high compression applications, such as mechanical counterpressure spacesuits. [18] However, SMPs offer superior material engineering strain (ε m ), defined as the change in material length in relation to a reference length (ε m,SMP > 100%; ε m,SMA < 8%).…”

Section: Introductionmentioning

confidence: 99%

Dynamic, Tunable, and Conformal Wearable Compression Using Active Textiles

Granberry

Pettys‐Baker

Woelfle

et al. 2022

Adv Materials Technologies

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New medical compression technologies that are simultaneously low‐profile, facile to don, and dynamic—applying medical compression only when needed—can expand the use of wearable compression, increase patient compliance, and lead to better medical outcomes. Dynamic and conformal wearable compression devices are presented that can be donned in a low‐stiffness state and transition into a high‐stiffness and, consequently, high‐compression state, on‐demand. These devices are enabled by active textiles developed from custom NiTi filaments that remain inactive at room temperature and accomplish actuation proximal to the human body surface. Further, these compression devices exploit NiTi material hysteresis to sustain a high‐compression state post‐heating and upon equilibrium with the body surface temperature for thermally‐comfortable, on‐body performance. Two case study examples—1) a consumer medical compression device and 2) a custom astronaut compression device—demonstrate the generalizability and flexibility of the engineering and design methods to develop a range of dynamic, tunable, and conformal compression devices with different goals and requirements. Further, this work demonstrates a roadmap for developing wearable systems that can accommodate a range of users without sacrificing system performance. This research opens doors for new NiTi‐based medical and consumer applications that interface with the body surface.

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