Temperature‐Memory Polymer Networks with Crystallizable Controlling Units

Kratz, Karl; Madbouly, Samy A.; Wagermaier, Wolfgang; Lendlein, Andreas

doi:10.1002/adma.201102225

Cited by 149 publications

(160 citation statements)

References 44 publications

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“…More precisely, this can be called stress based TME since the TME was reflected in the stress recovery event. The same effect was later confirmed by us and Lendlein's group for different polymers also with a broad thermal transition, confirming its generality [165,166]. While intriguing, the stress based TME may not be particularly relevant since most SMP applications relying on strain recovery instead of stress recovery.…”

Section: Tunable Multi-smps Via a Single Broad Thermal Phase Switchsupporting

confidence: 62%

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Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding

Zhao

Xie

2015

Progress in Polymer Science

1,191

749

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Shape memory polymers (SMPs), as a class of programmable stimuliresponsive shape changing polymers, are attracting increasing attention from the standpoint of both fundamental research and technological innovations. Following a brief introduction of the conventional shape memory effect (SME), progress in new shape memory enabling mechanisms and triggering methods, variations of in shape memory forms (shape memory surfaces, hydrogels, and microparticles), new shape memory behavior (multi-SME and two-way-SME), and novel fabrication methods are reviewed. Progress in thermomechanical modeling of SMPs is also presented. Abbreviations:SCPs shape changing polymers; LCEs liquid crystalline elastomers; SMP shape memory polymer; SME shape memory effect; 2W two-way; 1W oneway; T trans transition temperature; T g glass transition temperature; T m melting temperature; T cl liquid crystal cleaning temperature; T d deformation temperature; T f shape fixing temperature; T c crystallization temperature; R f shape stability ratio; R r shape recovery ratio; T sw switching temperature; ε max maximum recoverable strain; σ max maximum recovery stress; SMC shape memory cycle; ε load strain under load; ε fixed strain; T r recovery Page 2 of 106 A c c e p t e d M a n u s c r i p t 2 temperature; ε rec recovered strain; V r strain recovery rate; T σmax temperature corresponding to σ max ; T sw,app apparent switching temperature; PCL poly(ε-caprolactone); SMPU shape memory polyurethane; EMU elemental memory unit; TME temperature memory effect; PU polyurethane; T i liquid-crystal isotropic transition temperature; T v vitrification temperature; CIE crystallization induced elongation; MIC melting induced contraction

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Section: Tunable Multi-smps Via a Single Broad Thermal Phase Switchsupporting

confidence: 62%

“…A broad melting transition was also found equally effective. An ethylenevinyl acetate copolymer (EVA) typically possesses a relatively broad melting transition, with the T m value determined by the comonomer ratio [165]. By blending two EVAs of different comonomer ratios, the breadth of the T m transition could be extended to 100 °C.…”

Section: Page 32 Of 106mentioning

confidence: 99%

Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding

Zhao

Xie

2015

Progress in Polymer Science

1,191

749

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“…Figure 3a,b shows that a lower programming temperature has two effects: On the one hand, it results in a faster shape recovery rate. This phenomenon is referred as temperature memory effect of SMPs under free recovery condition 55,57,60 . On the other hand, however, it leads to lower shape fixity, indicating that a large portion of the programmed deformation is recovered right after unloading.…”

Section: Resultsmentioning

confidence: 99%

Reduced time as a unified parameter determining fixity and free recovery of shape memory polymers

2014

Nat Commun

235

179

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Shape memory polymers are at the forefront of recent materials research. Although the basic concept has been known for decades, recent advances in the research of shape memory polymers demand a unified approach to predict the shape memory performance under different thermo-temporal conditions. Here we report such an approach to predict the shape fixity and free recovery of thermo-rheologically simple shape memory polymers. The results show that the influence of programming conditions to free recovery can be unified by a reduced programming time that uniquely determines shape fixity, which consequently uniquely determines the shape recovery with a reduced recovery time. Furthermore, using the time-temperature superposition principle, shape recoveries under different thermo-temporal conditions can be extracted from the shape recovery under the reduced recovery time. Finally, a shape memory performance map is constructed based on a few simple standard polymer rheology tests to characterize the shape memory performance of the polymer.

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“…Increasing filler content resulted in more physical crosslinks in the system to serve as net points that play a critical role in SMP shape recovery and shape memory. 25, 26 Entropic recovery of SMPs is dependent on the net points within the system; hence, increasing net points and good nanoparticle/polymer bonding allowed for greater material recovery and expansion. 27, 28 Within the SiO 2 -loaded nanocomposites, the fastest actuation was observed with 0.5% filler.…”

Section: Resultsmentioning

confidence: 99%

Modification of shape memory polymer foams using tungsten, aluminum oxide, and silicon dioxide nanoparticles

et al. 2016

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Shape memory polymer (SMP) foams were synthesized with three different nanoparticles (tungsten, silicon dioxide, and aluminum oxide) for embolization of cerebral aneurysms. Ultra-low density SMP foams have previously been utilized for aneurysm occlusion, resulting in a rapid, stable thrombus. However, the small cross section of foam struts can potentially lead to fracture and particulate generation, which would be a serious adverse event for an embolic device. The goal of this study was to improve the mechanical properties of the system by physically incorporating fillers into the SMP matrix. Thermal and mechanical characterization suggested minimal changes in thermal transition of the SMP nanocomposites and improved mechanical strength and toughness for systems with low filler content. Actuation profiles of the three polymer systems were tuned with filler type and content, resulting in faster SMP foam actuation for nanocomposites containing higher filler content. Additionally, thermal stability of the SMP nanocomposites improved with increasing filler concentration, and particulate count remained well below accepted standard limits for all systems. Extraction studies demonstrated little release of silicon dioxide and aluminum oxide from the bulk over 16 days. Tungstun release increased over the 16 day examination period, with a maximum measured concentration of approxiately 2.87 μg/mL. The SMP nanocomposites developed through this research have the potential for use in medical devices due to their tailorable mechanical properties, thermal resisitivity, and actuation profiles.

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Temperature‐Memory Polymer Networks with Crystallizable Controlling Units

Cited by 149 publications

References 44 publications

Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding

Recent progress in shape memory polymer: New behavior, enabling materials, and mechanistic understanding

Reduced time as a unified parameter determining fixity and free recovery of shape memory polymers

Modification of shape memory polymer foams using tungsten, aluminum oxide, and silicon dioxide nanoparticles

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